https://thecavepearlproject.org/2024/04/20/a-practical-method-for-calibrating-ntc-thermistors/https://thecavepearlproject.org/wp-content/uploads/2024/04/202602_threewaterbathsinonerun_540pix.jpgTypical calibration bath runImage from the Cave Pearl Project: All three water baths in one continuous run.https://thecavepearlproject.org/wp-content/uploads/2024/04/20250127_ntcresolution_at35c.png20250127_NTCresolution_at35Chttps://thecavepearlproject.org/wp-content/uploads/2024/04/20250127_ntcresolution_at0c.png20250127_NTCresolution_at0Chttps://thecavepearlproject.org/wp-content/uploads/2024/04/ntccalredo2_560pixq.jpgNTCcalREDO2_560pixqhttps://thecavepearlproject.org/wp-content/uploads/2024/04/ntccalredo_481pixq.jpgNTCcalREDO_481pixqhttps://thecavepearlproject.org/wp-content/uploads/2024/04/calbiratedntcthermistors_validation_1024pixw.pngcalbiratedntcthermistors_validation_1024pixwhttps://thecavepearlproject.org/wp-content/uploads/2024/04/202404_ntccalibration_14_sensorconnection_640pixw.jpgTipping Bucket Rain GaugesImage from the Cave Pearl Project: NTC calbiration - attaching a reference sensor to the loggerhttps://thecavepearlproject.org/wp-content/uploads/2024/04/202404_ntccalibration_13_overlapcheck_640pixw-1.jpg202404_ntccalibration_13_overlapcheck_640pixw-1https://thecavepearlproject.org/wp-content/uploads/2024/04/202404_ntccalibration_13_overlapcheck_640pixw.jpg202404_ntccalibration_13_overlapcheck_640pixwhttps://thecavepearlproject.org/wp-content/uploads/2024/04/202404_ntccalibration_12_srscalculator_640pixw.jpg202404_ntccalibration_12_srscalculator_640pixw2026-03-09T17:12:42+00:00monthlyhttps://thecavepearlproject.org/2023/12/01/the-e360-a-classroom-data-logger-for-science/https://thecavepearlproject.org/wp-content/uploads/2023/12/3050ml_mountingbracket_byekm_202602.jpg2023 e360 Mounting BracketUniversal mounting bracket for the 2023 2-Part EDU ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods course. Also accomodates the 30ml self standing tubes.https://thecavepearlproject.org/wp-content/uploads/2023/12/glueline_securescoincell.jpgSecureCr2032coincellSecuring the CR2032 coincell with a line hot gluehttps://thecavepearlproject.org/wp-content/uploads/2023/12/2026_e360_currentranger.jpgTest e360 Sleep Current with CurrentRangerImage from the Cave Pearl Project, for the 2023 2-Part EDU ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods coursehttps://thecavepearlproject.org/wp-content/uploads/2023/12/e360_bmp280pircombination.jpge360 logger with PIR, BMP and 32k EEpromImage from the Cave Pearl Project, for the 2023 2-Part EDU ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods coursehttps://thecavepearlproject.org/wp-content/uploads/2023/12/2026_searchforsteps.jpg2026_SearchforStepshttps://thecavepearlproject.org/wp-content/uploads/2023/12/2026_setup_flowchart_jpeg.jpg2026 e360 Setup Code FlowchartImage from the Cave Pearl Project, for the 2023 2-Part EDU ProMini loggerhttps://thecavepearlproject.org/wp-content/uploads/2023/12/2026_startmenuoptionscreen-1.jpg2023 e360 2-Part Logger AssemblyImage from the Cave Pearl Project, for the 2-Part EDU ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods coursehttps://thecavepearlproject.org/wp-content/uploads/2023/12/2026_startmenuoptionscreen.jpg2023 e360 2-Part Logger AssemblyImage from the Cave Pearl Project, for the 2-Part EDU ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods coursehttps://thecavepearlproject.org/wp-content/uploads/2023/12/2025_hotgluebattery4_660pixw.jpg2025_HotGlueBattery4_660pixwhttps://thecavepearlproject.org/wp-content/uploads/2023/12/2025_hotgluebattery3_660pixw.jpg2025_HotGlueBattery3_660pixw2026-03-05T15:52:55+00:00monthlyhttps://thecavepearlproject.org/2022/03/09/powering-a-promini-logger-for-one-year-on-a-coin-cell/https://thecavepearlproject.org/wp-content/uploads/2022/03/202602_14mbatterycurve_137-m.jpgMrtcBatteryCurveImage from the Cave Pearl Project: 14 month CR2032 battery burn down curve on cave pearl logger with DS3231-M rtc that sleeps at 2360nAhttps://thecavepearlproject.org/wp-content/uploads/2022/03/202602_14mbatterycurve_141-sn.jpgrtc-SN battery burn down curveImage from the Cave Pearl Project: 1 14 month cr2032 battery burn down curve from a logger with a -SN rtc chip that sleep at only 1014nAhttps://thecavepearlproject.org/wp-content/uploads/2022/03/20250902_30mlmoisturegainvsdessicant.png20250902_30mlMoistureGainVSdessicanthttps://thecavepearlproject.org/wp-content/uploads/2022/03/20240923_2partloggerschematic_640x383pix.png20240923_2PartLoggerSchematic_640x383pixhttps://thecavepearlproject.org/wp-content/uploads/2022/03/rtc-sn_tempconv_norailcap_115msec_275ua_cranger_mvua.pngRTC-SN_TempConv_NoRailCap_115msec_275uA_CRanger_mv=uAhttps://thecavepearlproject.org/wp-content/uploads/2022/03/rtc-mtempconv_norailcap_10msec_220ua_crangeruamv.pngRTC-MtempConv_NoRailCap_10msec_220uA_Crangerua=mvhttps://thecavepearlproject.org/wp-content/uploads/2022/03/energiserc22032pulsedischarge_datasheetgraph.pngEnergiserC22032PulseDischarge_DatasheetGraphhttps://thecavepearlproject.org/wp-content/uploads/2022/03/2022_2partloggerschematic_noldr_640pixw.png2022_2PartLoggerSchematic_NoLDR_640pixwhttps://thecavepearlproject.org/wp-content/uploads/2022/03/2partrails5_intube_1024pixw_2024.jpg2023 e360 2-Part Logger AssemblyImage from the Cave Pearl Project, for the 2022 2-Part ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods coursehttps://thecavepearlproject.org/wp-content/uploads/2022/03/2partloggerrails_2024.jpg2023 e360 2-Part Logger AssemblyImage from the Cave Pearl Project, for the 2022 2-Part ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods course2026-02-28T18:51:25+00:00monthlyhttps://thecavepearlproject.org/2023/06/05/testing-cr2032-battery-discharge-time-with-our-2-part-promini-loggers/https://thecavepearlproject.org/wp-content/uploads/2023/06/conditioningcapacitorsbeforeuse_640pixh.jpgConditioningCapacitorsBeforeUse_640pixhhttps://thecavepearlproject.org/wp-content/uploads/2023/06/202501_furtherintocavecr2032battery.png202501_FurtherIntoCaveCr2032Batteryhttps://thecavepearlproject.org/wp-content/uploads/2023/06/202501_furtherintocavetemps.png202501_FurtherIntoCaveTempshttps://thecavepearlproject.org/wp-content/uploads/2023/06/202501_caveentrancecr2032battery.png202501_CaveEntranceCr2032Batteryhttps://thecavepearlproject.org/wp-content/uploads/2023/06/202501_caveentrancetemps.png202501_CaveEntranceTempshttps://thecavepearlproject.org/wp-content/uploads/2023/06/cr2032batterytests_3xled80ua_640pixw-1.jpgTipping Bucket Rain Gauges80uA sleep current Battery tests with 2-part falcon tube logger from the cave pearl projecthttps://thecavepearlproject.org/wp-content/uploads/2023/06/cr2032batterytests_redd13ledhigh1.4ma.jpgTipping Bucket Rain Gauges1.4mA cr2032 run test with RED D13 LED set highhttps://thecavepearlproject.org/wp-content/uploads/2023/06/202305_realsonycr2032_emboss.jpg202305_RealSonyCr2032_Embosshttps://thecavepearlproject.org/wp-content/uploads/2023/06/202305_fakesonycr2032_laser.jpg202305_FakeSonyCr2032_Laserhttps://thecavepearlproject.org/wp-content/uploads/2023/06/202305_fakesonycr2032_packaging.jpg202305_FakeSonyCr2032_Packaging2026-02-28T18:06:22+00:00monthlyhttps://thecavepearlproject.org/2024/08/10/using-a-bh1750-lux-sensor-to-measure-par/https://thecavepearlproject.org/wp-content/uploads/2024/08/cheapquantummeter.jpgCheapQuantumMeterhttps://thecavepearlproject.org/wp-content/uploads/2024/08/2020407_datafromdifferentdays.jpgTipping Bucket Rain GaugesImage from the Cave Pearl Projecthttps://thecavepearlproject.org/wp-content/uploads/2024/08/20240730_typicallightleveldata.png20240730_TypicalLightLevelDatahttps://thecavepearlproject.org/wp-content/uploads/2024/08/20240727_correlation_bhluxvspar_640pixw.jpgTipping Bucket Rain GaugesCorrelation: Diffused BH1750 Lux vs ClearSkyCalculator PAR on 2024-07-27https://thecavepearlproject.org/wp-content/uploads/2024/08/20240727_bhluxvsclearskypar_640pixw.jpgTipping Bucket Rain GaugesRaw BH1750 Lux vs Apoge ClearSky Model PAR: Image from the Cave Pearl Projecthttps://thecavepearlproject.org/wp-content/uploads/2024/08/202407_bh1750deploymentlocation1_640pixw.jpgTipping Bucket Rain GaugesDeployment Location1, BH1750 vs PAR Calibration. Image from the Cave Pearl Projecthttps://thecavepearlproject.org/wp-content/uploads/2024/08/apogeeclearskycalculator_409pixw.jpgApogeeClearSkyCalculator_409pixwhttps://thecavepearlproject.org/wp-content/uploads/2024/08/20240721-22_heatgaincomparison.jpgTipping Bucket Rain GaugesComparion of heat gain with, and withoug metal foil layers. Image from the Cave Pearl Project.https://thecavepearlproject.org/wp-content/uploads/2024/07/20240720_2commonbhsensormodules_640pixw-1.jpgTipping Bucket Rain GaugesTwo common BH1750 sensor moduleshttps://thecavepearlproject.org/wp-content/uploads/2024/07/shieldstack6_lowerirshield_640pixw-1.jpgTipping Bucket Rain GaugesLower IR shield on the stack. Image from the Cave Pearl Project.2026-02-20T17:28:50+00:00monthlyhttps://thecavepearlproject.org/2024/10/22/setting-accurate-rtc-time-with-a-gps-the-ds3231-aging-offset-to-reduce-drift/https://thecavepearlproject.org/wp-content/uploads/2024/10/20241209_ageoffsetscomparison_lrggroupsnvsm_640pixw.png20241209_AgeOffsetsComparison_LrgGroupSNvsM_640pixwhttps://thecavepearlproject.org/wp-content/uploads/2024/10/20241107_trendlineonrtcdrifttest_480pixw.png20241107_TrendlineonRtcDriftTest_480pixwhttps://thecavepearlproject.org/wp-content/uploads/2024/10/rtcbrokenedge_640pixw_202411.jpgTipping Bucket Rain GaugesImage from the Cave Pearl Project: EVIDENCE of rework on ds3231 rtc modulehttps://thecavepearlproject.org/wp-content/uploads/2024/10/20241031_initialreadingscompleted.png20241031_InitialReadingsCompletedhttps://thecavepearlproject.org/wp-content/uploads/2024/10/20241031_initialreadings4rtcdriftcheck.png20241031_InitialReadings4RTCdriftCheckhttps://thecavepearlproject.org/wp-content/uploads/2024/10/drifttest_79-sn_age-21_errorppm_test1.pngDriftTest_79-SN_Age-21_ErrorPPM_test1https://thecavepearlproject.org/wp-content/uploads/2024/10/drifttest_79-sn_age-21_msecdeltawgps_test1.pngDriftTest_79-SN_Age-21_MsecDeltawGPS_test1https://thecavepearlproject.org/wp-content/uploads/2024/10/drifttest_79-sn_age-21_tempsduringtest_test1.pngDriftTest_79-SN_Age-21_TempsDuringTest_test1https://thecavepearlproject.org/wp-content/uploads/2024/10/step1_ageregtest_68-m_202410.pngStep1_AgeRegTest_68-M_202410https://thecavepearlproject.org/wp-content/uploads/2024/10/drifttest_68-m_age-17_ppmerror_test2.pngDriftTest_68-M_Age-17_PPMerror_test22026-02-20T16:02:28+00:00monthlyhttps://thecavepearlproject.org/2023/04/15/insights-from-a-decade-of-tipping-bucket-rain-gauge-deployment/https://thecavepearlproject.org/wp-content/uploads/2023/04/20251210_leafcutterantsinclimatestation_680pxw.jpgTipping Bucket Rain GaugesImage from the Cave Pearl Project: here a leaf cutter ant colony has completely encapsulated the loggers in one of our climate stations.https://thecavepearlproject.org/wp-content/uploads/2023/04/20230430_c_siphonremoved.jpg20230430_c_SiphonRemovedhttps://thecavepearlproject.org/wp-content/uploads/2023/04/20230430_b_siphonmechanism.jpg20230430_b_SiphonMechanismhttps://thecavepearlproject.org/wp-content/uploads/2023/04/20230430_aa_siphonmechanism.jpg20230430_aa_SiphonMechanismhttps://thecavepearlproject.org/wp-content/uploads/2023/04/20230417_mechanismhighsierratrg_640pixh.jpgTipping Bucket Rain GaugesMechanism from High Sierra Electronics Tipping Bucket Rain Gaugehttps://thecavepearlproject.org/wp-content/uploads/2023/04/20230417_mechanismtexasonsettrg_640pixh.jpgTipping Bucket Rain GaugesInside a Texas Instruments Tipping bucket rain gauge.https://thecavepearlproject.org/wp-content/uploads/2023/04/20230417_photofromthelisting.jpg20230417_PhotoFromTheListinghttps://thecavepearlproject.org/wp-content/uploads/2023/04/20230417_interfacecloseup_1280pixw.jpg20230417_InterfaceCloseup_1280pixwhttps://thecavepearlproject.org/wp-content/uploads/2023/04/20230417_uppertipmechanism_640pixh.jpg20230417_UpperTipMechanism_640pixhhttps://thecavepearlproject.org/wp-content/uploads/2023/04/20230417_gaugemechanism_640pixh.jpg20230417_GaugeMechanism_640pixh2025-12-25T17:20:02+00:00monthlyhttps://thecavepearlproject.org/2023/05/24/a-diy-pressure-chamber-to-test-housings/https://thecavepearlproject.org/wp-content/uploads/2023/05/202305_mineraloil_frothinginhousing_640pixw.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/202305_nuncleak_640pixh.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/202305_bagleak_640pixh.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/202305_mineraloil_3submerged_640pixh-1.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/202305_mineraloil_3submerged_640pixh.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/202305_mineraloil_bagonly_640pixh.jpgTipping Bucket Rain GaugesOne logger was submerged using a sample bag so that we could pressure test the internal chips.https://thecavepearlproject.org/wp-content/uploads/2023/05/202305_mineraloil_tubefills_640pixh.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/202305_30ml_3_cracklid_640pixh.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/20230423_30ml_crushabove50psi_640pixh.jpgTipping Bucket Rain Gaugeshttps://thecavepearlproject.org/wp-content/uploads/2023/05/2023_50mltubes_2_640pixh.jpgTipping Bucket Rain Gauges2025-09-19T17:46:44+00:00monthlyhttps://thecavepearlproject.org/2023/03/17/waterproofing-your-electronics-project/https://thecavepearlproject.org/wp-content/uploads/2023/03/trishwwaspsintiprg_640pixh.jpgDr. Beddows removing a wasp nest from one of our climate stations...again..Dr. Beddows removing a wasp nest from one of our climate stations...again..https://thecavepearlproject.org/wp-content/uploads/2023/03/hotgluecork.jpgHotGlueCorkhttps://thecavepearlproject.org/wp-content/uploads/2023/03/ssd1306_oled_warduino_pt10_testafterexpoxy-1.jpgssd1306_oled_warduino_pt10_testafterexpoxy-1https://thecavepearlproject.org/wp-content/uploads/2023/03/ssd1306_oled_warduino_pt10_testafterexpoxy.jpgSSD1306_OLED_wArduino_Pt10_TestAfterExpoxyhttps://thecavepearlproject.org/wp-content/uploads/2023/03/conformalcoating_stboard_320pixw.jpgconformalcoating_stboard_320pixwhttps://thecavepearlproject.org/wp-content/uploads/2023/03/mineraloilmount_interior_640pixh.jpgDIY Mineral Oil mounting for pressure sensorsDIY Mineral Oil mounting for pressure sensorshttps://thecavepearlproject.org/wp-content/uploads/2023/03/mineraloilmount_join2parts_640pixh.jpgMineral Oil mounting for pressure sensorsMineral Oil mounting for pressure sensorshttps://thecavepearlproject.org/wp-content/uploads/2023/03/mineraloilmount_bothcomponents_640pixh.jpgDIY Mineral Oil mounting for pressure sensorsDIY Mineral Oil mounting for pressure sensorshttps://thecavepearlproject.org/wp-content/uploads/2023/03/hotglueheatshrink-1.jpgHotGlue&HeatShrinkhttps://thecavepearlproject.org/wp-content/uploads/2023/03/user8886.jpguser88862025-09-09T17:04:34+00:00monthlyhttps://thecavepearlproject.org/2019/03/25/using-arduinos-input-capture-unit-for-high-resolution-sensor-readings/https://thecavepearlproject.org/wp-content/uploads/2019/03/noisythermistor2.jpgCave Pearl data loggersThermistor reading with regulator removedhttps://thecavepearlproject.org/wp-content/uploads/2019/03/noisythermistor1.jpgCave Pearl data loggersnoisy ICU based Thermistor readings caused by bad regulatorhttps://thecavepearlproject.org/wp-content/uploads/2019/03/y5vtempcoefficient.jpgY5VtempCoefficienthttps://thecavepearlproject.org/wp-content/uploads/2019/03/10krefvsinternalpullupref_icutimingmethod.jpgCave Pearl data loggersComparing post -calibration results from using the 10k reference, vs the internal pullup resistance for ICU timing ratio determination of temperature from a thermistorhttps://thecavepearlproject.org/wp-content/uploads/2019/03/si7051vs5kosvs10kicu.jpgCave Pearl data loggersA comparison of oversampled thermistor vs ICT timing thermistor vs si7051https://thecavepearlproject.org/wp-content/uploads/2019/03/icuntcthermistorcircuitwith10kreference_640px.pngICU&NTCthermistorCircuitwith10kReference_640pxhttps://thecavepearlproject.org/wp-content/uploads/2019/03/ulongvariableoverflow.pngULONGvariableOverflowIf your graphs start looking like this at colder temperatureshttps://thecavepearlproject.org/wp-content/uploads/2019/03/icuntcthermistorcircuit_300px.pngICU&NTCthermistorCircuit_300pxhttps://thecavepearlproject.org/wp-content/uploads/2019/03/an685_calculation.pngAN685_calculationhttps://thecavepearlproject.org/wp-content/uploads/2019/03/an685_figure8.pngAN685_FIGURE8AN685 FIGURE 8: The RC time response of the circuit allows for the microcontroller counter to be used to determine the relative resistance of the NTC element.2025-08-17T14:39:38+00:00monthlyhttps://thecavepearlproject.org/2024/05/01/how-to-normalize-a-set-of-pressure-sensors/https://thecavepearlproject.org/wp-content/uploads/2024/05/humiditysensortestbyliutyi.jpegHumiditySensorTestbyLiutyihttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_16-b_pressuresensormount_crop.jpgTipping Bucket Rain GaugesImage from the Cave Pearl Project: A MS58x series pressure sensor mounted under mineral oil with a finger cott membranehttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_16_pressuresensormount.jpgTipping Bucket Rain GaugesImage from the Cave Pearl Project: A MS58x series pressure sensor mounted under mineral oil with a finger cott membranehttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_15_ntcvalidation.png20240429_pnorm_15_ntcvalidationhttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_14_ntcnormalization_a-1.png20240429_pnorm_14_ntcnormalization_a-1https://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_14_ntcnormalization_a.png20240429_pnorm_14_ntcnormalization_ahttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_13_ntcnormalization.png20240429_pnorm_13_ntcnormalizationhttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_12_airportcomparison.png20240429_pnorm_12_airportcomparisonhttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_11_beforenafternormalization.png20240429_pnorm_11_beforenafternormalizationhttps://thecavepearlproject.org/wp-content/uploads/2024/04/20240429_pnorm_10_betterresidualsgraph3.png20240429_pnorm_10_betterresidualsgraph32025-03-05T22:06:41+00:00monthlyhttps://thecavepearlproject.org/how-to-build-an-arduino-data-logger/https://thecavepearlproject.org/wp-content/uploads/2023/12/e360loggerintube_320pixw.jpg2023 e360 2-Part Logger AssemblyImage from the Cave Pearl Project, for the 2023 2-Part EDU ProMini logger developed for NorthWestern Universities E360 instrumentation & field methods coursehttps://thecavepearlproject.org/wp-content/uploads/2023/12/20231128_e360_schematic_400x240.png20231128_e360_schematic_400x240https://thecavepearlproject.org/wp-content/uploads/2023/11/20231128_e360_schematic-01-1.png20231128_e360_schematic-01https://thecavepearlproject.org/wp-content/uploads/2023/03/minilogger_sensorcloseup_640pixh.jpgMiniLogger_SensorCloseup_640pixhA 30mL freestanding centrifuge tube makes a perfect housing for the new 2-part Mini-loggershttps://thecavepearlproject.org/wp-content/uploads/2019/01/cavepearl_studentbuild2019_300pxw.jpgCave Pearl data loggersPro Mini based data logger from the cave pearl project. This version designed for STEM education classroom projects. 2019https://thecavepearlproject.org/wp-content/uploads/2018/11/cave-pearl-academic-paper-from-sensors-_2018.jpgCave Pearl Academic paper from Sensors _2018A low-cost data logging platform is presented that provides long-term operation in remote or submerged environments. This paper describes a complete DIY solution, suitable for a wide range of challenging deployment conditions. Three premade “breakout boards” from the open-source Arduino ecosystem are assembled into the core of the data logger. Power optimization techniques are presented which extend the operational life of this module-based design to >1 year on three alkaline AA batteries. Robust underwater housings are constructed for these loggers using PVC fittings.https://thecavepearlproject.org/wp-content/uploads/2018/10/cave-pearl-academic-paper-from-sensors-journal-2018.jpgCave Pearl data loggersAcademic paper describing a DIY 3-module arduino based data logger with underwater housings and case studies describing real world deployments.https://thecavepearlproject.org/wp-content/uploads/2018/10/youtubetutorials.jpgCave Pearl data loggersA set of tutorial videos to guide people through the Pro Mini Data Logger assembly releaseed by the Cave Pearl Project in 2017https://thecavepearlproject.org/wp-content/uploads/2018/02/20180210_cavepearllogger_prominivariant_1240pix.png20180210_CavePearlLogger_ProMiniVariant_1240pix2025-01-31T23:48:52+00:00weekly0.6https://thecavepearlproject.org/about/about-me/2025-01-23T21:03:42+00:00weekly0.6https://thecavepearlproject.org/2015/03/30/using-ds18b20-one-wire-sensors-to-make-a-diy-thermistor-string-pt-2-calibration/2025-01-21T16:49:43+00:00monthlyhttps://thecavepearlproject.org/2014/05/21/using-a-cheap-3-ds3231-rtc-at24c32-eeprom-from-ebay/https://thecavepearlproject.org/wp-content/uploads/2014/05/rimg1535.jpgCave Pearl data loggerssimpler RTC modification for low power logger operationhttps://thecavepearlproject.org/wp-content/uploads/2014/05/ds3231_d1mini.jpgds3231_d1minihttps://thecavepearlproject.org/wp-content/uploads/2014/05/ds3231_rstpullup.pngds3231_rstpullupRST pin has an internal 50k nominal value pullup resistor to VCChttps://thecavepearlproject.org/wp-content/uploads/2014/05/ds3231_mod4vbatonlypower.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2014/05/ds3231pinout.jpgDS3231pinouthttps://thecavepearlproject.org/wp-content/uploads/2014/05/pi_ds3231rtc1.jpgPI_ds3231RTChttps://thecavepearlproject.org/wp-content/uploads/2014/05/pi_ds3231rtc.jpgPI_ds3231RTChttps://thecavepearlproject.org/wp-content/uploads/2014/05/keystudio0039_ds3231rtc.jpgKeystudio0039_ds3231RTChttps://thecavepearlproject.org/wp-content/uploads/2017/06/rtc_pinpower.jpgCave Pearl data loggers2024-12-16T19:30:48+00:00monthlyhttps://thecavepearlproject.org/2015/06/15/developing-an-arduino-based-weather-station/https://thecavepearlproject.org/wp-content/uploads/2022/09/tiprg_typicalsite_6_640pixw.jpghttps://thecavepearlproject.org/https://thecavepearlproject.org/https://thecavepearlproject.org/wp-content/uploads/2022/09/tulumtiprg_3_400pixh-1.jpgtulumtiprg_3_400pixh-1https://thecavepearlproject.org/wp-content/uploads/2022/09/tulumtiprg_2_400pixh.jpghttps://thecavepearlproject.org/https://thecavepearlproject.org/https://thecavepearlproject.org/wp-content/uploads/2022/09/tulumtiprg_1_400pixh.jpgtulumtiprg_1_400pixhRainGauge On Rooftop in Tulum. An instrument from the open source arduino based Cave Pearl Project.https://thecavepearlproject.org/wp-content/uploads/2022/09/tulumtiprg_3_400pixh.jpgtulumtiprg_3_400pixhhttps://thecavepearlproject.org/wp-content/uploads/2022/09/tiprg_fail_5_600pixw.jpghttps://thecavepearlproject.org/https://thecavepearlproject.org/https://thecavepearlproject.org/wp-content/uploads/2022/09/tiprg_fail_4_400pixh.jpgtiprg_fail_4_400pixhhttps://thecavepearlproject.org/wp-content/uploads/2015/06/liutiy_surveyofhumiditysensors.jpgliutiy_surveyofhumiditySensorshttps://thecavepearlproject.org/wp-content/uploads/2015/06/additonalscreenonraingaugefunnel.jpgCave Pearl data loggersHere a drain screen is added to catch the fines that make it through the larger screen in the rain gauge filter.https://thecavepearlproject.org/wp-content/uploads/2015/06/freestation_dogbowlstevensshield.jpgFreeStation_DogBowlStevensShield2024-11-03T00:04:59+00:00monthlyhttps://thecavepearlproject.org/2014/03/27/adding-a-ms5803-02-high-resolution-pressure-sensor/https://thecavepearlproject.org/wp-content/uploads/2014/03/damagedpressuresensor_640pix.jpgCave Pearl data loggersThe protective silicone cap does not withstand hypersaline environmentshttps://thecavepearlproject.org/wp-content/uploads/2014/03/biofoulingonpressuresensor.jpgCave Pearl data loggersBiofouling after 6 months in a ocean esturary river.https://thecavepearlproject.org/wp-content/uploads/2014/03/standardpottingofpressuresensor_600pxw.jpgCave Pearl data loggersStandard sensor mount in a pex plumbing fitting with E30-CL epoxy around the boardhttps://thecavepearlproject.org/wp-content/uploads/2014/03/exposedms5803sensor_640px.jpgCave Pearl data loggersView of MS5803 sensor after the protective cover was accidentally knocked offhttps://thecavepearlproject.org/wp-content/uploads/2014/03/knotshouldbefreetomoveinsidetube_600pxw.jpgCave Pearl data loggersPart of a series of photos showing how to mount pressure sensors under mineral oilhttps://thecavepearlproject.org/wp-content/uploads/2014/03/tightenlockring_600pxw.jpgCave Pearl data loggersPart of a series of photos showing how to mount pressure sensors under mineral oilhttps://thecavepearlproject.org/wp-content/uploads/2014/03/pushbaloonbackabit_7_600pxw.jpgCave Pearl data loggersPart of a series of photos showing how to mount pressure sensors under mineral oilhttps://thecavepearlproject.org/wp-content/uploads/2014/03/mountbaloononmineraloil_8_600pxw.jpgCave Pearl data loggersPart of a series of photos showing how to mount pressure sensors under mineral oilhttps://thecavepearlproject.org/wp-content/uploads/2014/03/addmineraloiltosensor_6_600pxw.jpgCave Pearl data loggersPart of a series of photos showing how to mount pressure sensors under mineral oilhttps://thecavepearlproject.org/wp-content/uploads/2014/03/balloonrimremoved_5_600pxw.jpgCave Pearl data loggersPart of a series of photos showing how to mount pressure sensors under mineral oil2024-10-24T13:49:52+00:00monthlyhttps://thecavepearlproject.org/2018/02/03/measuring-temperature-with-two-clocks/https://thecavepearlproject.org/wp-content/uploads/2018/02/watchdogoscilatorfrequency.pngWatchdogOscilatorFrequencyhttps://thecavepearlproject.org/wp-content/uploads/2018/02/prtdrift.jpgPRTdrifthttps://thecavepearlproject.org/wp-content/uploads/2018/02/fig6_logerhousings640px.jpgFig6_LogerHousings640pxhttps://thecavepearlproject.org/wp-content/uploads/2018/02/clocktickvariationwtemp_pmclone.jpgCave Pearl data loggersThis graph was created by counting the number of system clock tick during a 1Hz pulse from a DS3231 RTC. The count was captured with Nick Gammon's Input Capture Method (see <a href="https://www.gammon.com.au/forum/?id=11504" target="_blank" rel="noopener">reply #12</a>) on pin D8. The red line is the temperature in °C from an si7051<a href="https://www.silabs.com/documents/public/data-sheets/Si7050-1-3-4-5-A20.pdf" target="_blank" rel="noopener"> reference</a> [±0.13 °C: 20.0 °C to 70.0 °C] (left axis, Celcius), and the orange line is the corresponding change in the count (right axis, freq.(-798000)).https://thecavepearlproject.org/wp-content/uploads/2018/02/miniultrafail_1240pix.pngMiniUltraFail_1240pixhttps://thecavepearlproject.org/wp-content/uploads/2018/02/thesimple_pmclone.jpgTheSimple_PMclonethe board https://thecavepearlproject.org/wp-content/uploads/2018/02/arcticconditionssimulationfacility_300px.jpgArcticConditionsSimulationFacility_300pxOne problem with pushing the cal box down to sub-zero temps is that the compressor cycle can still make it through to muck up your data. If you live in a suitable climate, natural weather systems make for much better data, and they have the added benefit that you spouse doesn't gripe at you because they can't find the chicken to make dinner because you have https://thecavepearlproject.org/wp-content/uploads/2018/02/potinpot.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2018/02/tempvscountvariation_linear.pngTEMPvsCountVariation_linearhttps://thecavepearlproject.org/wp-content/uploads/2018/02/ds3231tempregister.pngDS3231tempRegister2024-10-23T21:34:34+00:00monthlyhttps://thecavepearlproject.org/2017/11/03/configuring-i2c-sensors-with-arduino/https://thecavepearlproject.org/wp-content/uploads/2017/11/multii2c.jpgMultiI2Chttps://thecavepearlproject.org/wp-content/uploads/2017/11/tmp102dataretrievaltiming.jpgTMP102dataRetrievalTiminghttps://thecavepearlproject.org/wp-content/uploads/2017/11/compilerwarnings2_png.pngCompilerwarnings2_pnghttps://thecavepearlproject.org/wp-content/uploads/2017/11/compilerwarnings1_png.pngCompilerwarnings1_pnghttps://thecavepearlproject.org/wp-content/uploads/2017/11/3xultrasonic.jpg3xUltrasonichttps://thecavepearlproject.org/wp-content/uploads/2017/11/attinyi2cinterface.jpgATtinyI2Cinterfacehttps://thecavepearlproject.org/wp-content/uploads/2017/11/sensormounting.jpgCave Pearl data loggersAfter testing the raw sensors, I mount them in expoxy.https://thecavepearlproject.org/wp-content/uploads/2017/11/sensorpan.jpgCave Pearl data loggersA selection of I2C sensors being tested togetherhttps://thecavepearlproject.org/wp-content/uploads/2017/11/lsm303board1.jpgLSM303boardhttps://thecavepearlproject.org/wp-content/uploads/2017/11/mcp9808_tempregister.jpgMCP9808_tempRegister2024-10-15T17:47:21+00:00monthlyhttps://thecavepearlproject.org/2015/03/01/using-ds18b20-sensors-to-make-a-diy-thermistor-string-pt-1-the-build/2024-08-19T20:12:16+00:00monthlyhttps://thecavepearlproject.org/2020/05/21/using-the-ads1115-in-continuous-mode-for-burst-sampling/https://thecavepearlproject.org/wp-content/uploads/2020/05/ads1115inputimpedance.jpgADS1115inputImpedanceLow input impedance can prevent you from using the higher gain settingshttps://thecavepearlproject.org/wp-content/uploads/2020/05/ads1115_breadboardsetupwpiezo.jpgCave Pearl data loggersTesting configuration reading a raw piezo sensor with an ADS1115 modulehttps://thecavepearlproject.org/wp-content/uploads/2020/05/x9c_digitalpotwopamp.jpgX9C_digitalPotwOpamphttps://thecavepearlproject.org/wp-content/uploads/2020/05/ads1115piezo_860sps16x_prefetch4-1.jpgCave Pearl data loggersPiezo signal captured with ADS1115 ADC at 860sps, 16xpga, differntialhttps://thecavepearlproject.org/wp-content/uploads/2020/05/ads1115piezo_860sps16x_prefetch3.jpgCave Pearl data loggersPiezo signal captured with ADS1115 ADC at 860sps, 16xpga, differntialhttps://thecavepearlproject.org/wp-content/uploads/2020/05/ads1115piezo_860sps16x_prefetch2-1.jpgCave Pearl data loggersPiezo signal captured with ADS1115 ADC at 860sps, 16xpga, differntialhttps://thecavepearlproject.org/wp-content/uploads/2020/05/ads1115piezo_860sps16x_prefetch1.jpgCave Pearl data loggersPiezo signal captured with ADS1115 ADC at 860sps, 16xpga, differntialhttps://thecavepearlproject.org/wp-content/uploads/2020/05/thresholdtrigger_2_aliasingmainshum.jpgThresholdTrigger_2_Aliasing&MainsHumhttps://thecavepearlproject.org/wp-content/uploads/2020/05/thresholdtrigger_1_ads1115piezo.jpgCave Pearl data loggersthreshold triggered sample from ADS1115 with piezohttps://thecavepearlproject.org/wp-content/uploads/2020/05/ads1115_configregister.pngADS1115_ConfigRegister2024-08-16T22:06:22+00:00monthlyhttps://thecavepearlproject.org/2019/08/30/creating-a-normalized-vegetation-index-sensor-with-two-leds/https://thecavepearlproject.org/wp-content/uploads/2019/08/osraman147_fig2.jpgOsramAN147_fig2https://thecavepearlproject.org/wp-content/uploads/2019/08/pseudondvi_ledconnections_640px.jpgPseudoNDVI_LEDconnections_640pxhttps://thecavepearlproject.org/wp-content/uploads/2019/08/chromatographyvideolink.jpgChromatographyVideoLinkhttps://thecavepearlproject.org/wp-content/uploads/2019/08/10_olddeadfallleaf-1.jpg#10_OldDeadfallLeafhttps://thecavepearlproject.org/wp-content/uploads/2019/08/18_yellowpalm_otherstressedplant.jpg#18_YellowPalm_OtherStressedPlanthttps://thecavepearlproject.org/wp-content/uploads/2019/08/16_greenpalm_healthyplant.jpg#16_GreenPalm_HealthyPlanthttps://thecavepearlproject.org/wp-content/uploads/2019/08/15_yellowleaf_fromstressedplant.jpg#15_YellowLeaf_fromStressedPlanthttps://thecavepearlproject.org/wp-content/uploads/2019/08/14_greenpalm_fromstressedplant.jpg#14_GreenPalm_fromStressedPlanthttps://thecavepearlproject.org/wp-content/uploads/2019/08/13_50yellow_400pxh.jpg#13_50%Yellow_400pxhhttps://thecavepearlproject.org/wp-content/uploads/2019/08/12_healthygreen_400pixh.jpg#12_HealthyGreen_400pixh2024-08-14T14:50:28+00:00monthlyhttps://thecavepearlproject.org/2017/04/26/calibrating-oversampled-thermistors-with-an-arduino/https://thecavepearlproject.org/wp-content/uploads/2017/04/spikesfromrailvoltagecorrection.jpgSpikesfromRailVoltageCorrectionhttps://thecavepearlproject.org/wp-content/uploads/2017/04/thermcalrun_freezer_fridge_room.jpgCave Pearl data loggersI've found that Freezer (morning)->Fridge(afternoon)->Room (overnight) gives enough time at each temp to sort out thermal lag issues2024-07-23T20:58:06+00:00monthlyhttps://thecavepearlproject.org/2020/10/27/hacking-a-capacitive-soil-moisture-sensor-for-frequency-output/https://thecavepearlproject.org/wp-content/uploads/2020/10/2021-03-04_updatedsoilsensorschematic-2.jpgCave Pearl data loggersSchematic before conversion: (regulator not shown). The output frequency is controlled by the <a href="https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-time-constant" target="_blank" rel="noopener">time constant</a> when charging/discharging C3 through R2/R3. Gadget Reboot gives a good overview of <a style="color:#ff0000;" href="https://www.youtube.com/watch?v=pdGRs7GXBeE" target="_blank" rel="noopener">how the basic configuration works</a>, feeding the RC filtered 555 output <a href="http://www.caffeineowl.com/electronics/rants/dfrobot-capacitive-probe/index.html" target="_blank" rel="noopener">into</a> a simple <a href="https://www.youtube.com/watch?v=ic_yEUV7Y3c&ab_channel=Afrotechmods" target="_blank" rel="noopener">peak detector</a>. The <a style="color:#000000;" href="https://www.mdpi.com/1424-8220/20/12/3585" target="_blank" rel="noopener">V1.2 probes with the TLC555 run at a higher 1.5Mhz frequency</a> with a 34% duty cycle.https://thecavepearlproject.org/wp-content/uploads/2020/10/heatshrinkseparating_fromsoilsensors.jpgCave Pearl data loggersHeat Shrink separated from the smooth soil sensor surfaces over timehttps://thecavepearlproject.org/wp-content/uploads/2020/10/soilstayssaturatedafterleaffall-1.jpgCave Pearl data loggersWith no more evapotranspiration, the soil stays saturated.https://thecavepearlproject.org/wp-content/uploads/2020/10/adhesiveheatshrink_onsoilsensor.jpgCave Pearl data loggersMarine heat shrink mounting for capacitive soil moisture sensorshttps://thecavepearlproject.org/wp-content/uploads/2020/10/2020_analogsoilsensor_defaultadcread_5cmdepth_3v.jpgCave Pearl data loggersAnalog data from unmodified capacitivie soil moisture sensor running in our back yard during the driest month of the year (at 5cm depth)https://thecavepearlproject.org/wp-content/uploads/2020/10/2020_freqhacksoil_labeled.jpgCave Pearl data loggersFaiture of Frequency Hacked Soil moisture probe - low frequency was leading to self polarization.https://thecavepearlproject.org/wp-content/uploads/2020/08/soilmoistureprobe_freqmodified_schematic.pngSoilMoistureProbe_FreqModified_SchematicThere isn't much left after the mod. It's important to <a href="https://electronics.stackexchange.com/questions/257098/large-voltage-spikes-on-charge-pump-output/257128#257128" target="_blank" rel="noopener">leave the C1 bypass in place</a> but I haven't had problems pin-powering other sensor boards with similar caps. It's the bare minimum you can get away with on a 555 so if you get too many bad reads or weird spikes try adding another stabilization cap to the empty C5/C6 pads.https://thecavepearlproject.org/wp-content/uploads/2020/08/capacitivesoilmoisturesensor_originalschematic.pngCapacitiveSoilMoistureSensor_OriginalSchematicSchematic before conversion: (regulator not shown). The output frequency is controlled by the <a href="https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-time-constant" target="_blank" rel="noopener">time constant</a> when charging C3 through R2 & R3. Gadget Reboot gives a good overview of <a href="https://www.youtube.com/watch?v=pdGRs7GXBeE" target="_blank" rel="noopener">how the basic configuration works</a>, feeding the RC filtered 555 output into a simple <a href="http://www.caffeineowl.com/electronics/rants/dfrobot-capacitive-probe/index.html" target="_blank" rel="noopener">peak detector</a>. Though it's worth noting that <a href="https://www.mdpi.com/1424-8220/20/12/3585" target="_blank" rel="noopener">V1.2 probes with the TLC555 run at a higher1.5Mhz frequency</a> with a 34% duty cycle.https://thecavepearlproject.org/wp-content/uploads/2020/07/soilmoistureprobe_freqmodified_schematic.pngSoilMoistureProbe_FreqModified_Schematichttps://thecavepearlproject.org/wp-content/uploads/2020/07/capacitivesoilmoisturesensor_originalschematic.pngCapacitiveSoilMoistureSensor_OriginalSchematicOriginal schematic before conversion (regulator not shown). The output frequency is controlled by the charging of C3 through R2 & R3. When the probe is completely immersed in water, it's capacitance is close to 470 pF.2024-07-12T16:22:54+00:00monthlyhttps://thecavepearlproject.org/2020/10/22/pro-mini-classroom-datalogger-2020-update/https://thecavepearlproject.org/wp-content/uploads/2020/10/2020_cavepearl_datalogger_partskit_640pxw.jpgCave Pearl data loggersCave Pearl Classroom logger [2020 revision] parts photo. Note that the cable glands are not necessary unless your sensors require them, and 2x as many dupont jumper wires are shown to provide spares.https://thecavepearlproject.org/wp-content/uploads/2020/10/2020logger_afterassembly_600pixw.jpgCave Pearl data loggers2020 Pro Mini based logger from the Cave Pearl Project - Before Addition of sensor moduleshttps://thecavepearlproject.org/wp-content/uploads/2020/10/2020_logger_sdmodulewires3_600pxw.jpgCave Pearl data loggersAdd single wires from the 20cm Dupont cable. Red=3v3, Grey=CableSelect, Orange=MOSI, Brown=CLocK, Purple=MISO, Black=GNDhttps://thecavepearlproject.org/wp-content/uploads/2020/10/2020_prominilogger_sdmoduleconnections1_600px.jpgCave Pearl data loggersAdd https://thecavepearlproject.org/wp-content/uploads/2020/10/2020_sdmoduleconnections_2_600pixw.jpgCave Pearl data loggersSD Connection pattern: Grey (CS) to ProMini D10, Orange (MOSI) -> pm D11, Purple (MISO) ->pm D12, Brown (CLK) -> pm D13 (NOTE the shield labels say A0-A3 which do not match the D10-13 pattern of the Pro Mini pins)https://thecavepearlproject.org/wp-content/uploads/2020/10/2020_bendwireback.jpgCave Pearl data loggersBend the wire back to provide more copper under the screwterminalshttps://thecavepearlproject.org/wp-content/uploads/2020/10/2020_2xliaa_affectedbylowtemps_640-1.jpg2020_2xLiAA_AffectedByLowTemps_640https://thecavepearlproject.org/wp-content/uploads/2020/10/insidebreadboard_600px-1.jpgInsideBreadboard_600pxThe connections inside the breadboard.https://thecavepearlproject.org/wp-content/uploads/2020/10/2020_moistureonlidoflogger.jpgCave Pearl data loggersIt's always a bad sign to see moisture condensing on the lid of your loggerhttps://thecavepearlproject.org/wp-content/uploads/2020/10/samecircuitwsolidcorewires-2.jpgCave Pearl data loggersSolid Core wires let you run the power rails under the sensor2024-07-03T01:29:29+00:00monthlyhttps://thecavepearlproject.org/2020/11/15/adding-two-oled-displays-to-your-arduino-logger-with-no-library/https://thecavepearlproject.org/wp-content/uploads/2020/11/2020_dualoledscreens_classroomloggerbuild_640px.jpgCave Pearl data loggersHot glue aligns two 0.96" OLED screens on the lid of a classroom loggerhttps://thecavepearlproject.org/wp-content/uploads/2020/11/2020_dualoled_hotglue1_600px.jpgCave Pearl data loggersHot glue attaches the OLED screens to the top of the plano box used with our student logger buildhttps://thecavepearlproject.org/wp-content/uploads/2020/11/oled_bargraphvariant.jpgCave Pearl data loggersBar graph variant on OLEDhttps://thecavepearlproject.org/wp-content/uploads/2020/11/oled_histogram.jpgCave Pearl data loggersStandard Histogram plot on OLED screenhttps://thecavepearlproject.org/wp-content/uploads/2020/11/oled_lineplot.jpgCave Pearl data loggersStandard line plot on OLED screenhttps://thecavepearlproject.org/wp-content/uploads/2020/11/2020_screen1_text_600px.jpgCave Pearl data loggersOLED display of text & progress bars using the horizontal access mode of the ssd1306 displayhttps://thecavepearlproject.org/wp-content/uploads/2020/11/2020_oledscreenmodificaitons_600px.jpgCave Pearl data loggersI2C OLED - four modifications for dual screen setup & low power operationhttps://thecavepearlproject.org/wp-content/uploads/2020/11/classroomlogger_dualoled_displays_640px.jpgCave Pearl data loggers2020 classroom logger with dual I2C OLED screens.https://thecavepearlproject.org/wp-content/uploads/2020/11/dualoledscreens_1_600px.jpgCave Pearl data loggersTwo I2C 0.96" OLED displays make highly useful additions to the basic three module logger2023-12-10T17:58:35+00:00monthlyhttps://thecavepearlproject.org/2015/05/22/calibrating-any-compass-or-accelerometer-for-arduino/2023-12-09T19:09:08+00:00monthlyhttps://thecavepearlproject.org/2020/04/08/diy-data-logger-housing-from-pvc-parts-2020-update/https://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_8_cavepearlproject_640px.jpgCave Pearl data loggersPass through style sensor cap to match the lower half of the housinghttps://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_11_cavepearlproject_640px.jpgCave Pearl data loggersCave Pearl Projects complete 2-cap housing design with sensors attached March 2020https://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_10_cavepearlproject_640px.jpgCave Pearl data loggersCompleted Cave Pearl Project "2-Cap" housinghttps://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_7b_cavepearlproject_640px.jpgCave Pearl data loggersClamp when gluing the pass-through to the upper caphttps://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_7_cavepearlproject_640px.jpgCave Pearl data loggersSensor breakouts on logger stackhttps://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_7a_cavepearlproject_640px.jpgCave Pearl data loggers2xAA battery stack is just under 6cm longhttps://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_6_cavepearlproject_640px.jpgCave Pearl data loggersAdd breakouts for sensorshttps://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_5_cavepearlproject_640px.jpgCave Pearl data loggersThe logger stack fits nicely into the O-ring backer tubehttps://thecavepearlproject.org/wp-content/uploads/2020/04/2caphousing_4_cavepearlproject_640px.jpgCave Pearl data loggersHere the logger stack from 2017 has a 2xAA battery pack taped to the bottomhttps://thecavepearlproject.org/wp-content/uploads/2020/04/cavepearlproject_2caphousing_2_640px.jpgCave Pearl data loggersThen 5.5cm tube serves as an o-ring backer2023-05-27T15:30:37+00:00monthlyhttps://thecavepearlproject.org/2021/05/10/timing-an-led-light-sensor-with-pin-change-interrupts/https://thecavepearlproject.org/wp-content/uploads/2021/04/20210502_5050ledbsbh1750_1200pixw.jpgCave Pearl data loggersCross calbiration: Red channel of 5050 LED use in reverse bias light sensing mode VS BH1750 LUX sensor2022-11-25T22:55:25+00:00monthlyhttps://thecavepearlproject.org/2017/05/21/switching-off-sd-cards-for-low-power-data-logging/https://thecavepearlproject.org/wp-content/uploads/2017/05/1gbnonamecard_250mvdrop.jpg1GBnonameCard_250mvDrophttps://thecavepearlproject.org/wp-content/uploads/2017/05/nokia256_nodrop.jpgNokia256_NoDrophttps://thecavepearlproject.org/wp-content/uploads/2017/05/muvemusic1gb-3gb.pngMUVEmusic1Gb-3Gbhttps://thecavepearlproject.org/wp-content/uploads/2017/05/sandisk32gbultra.pngSanDisk32GBUltrahttps://thecavepearlproject.org/wp-content/uploads/2017/05/noname1gb.pngNoName1gbhttps://thecavepearlproject.org/wp-content/uploads/2017/05/sandisk2gb.pngSanDisk2gbhttps://thecavepearlproject.org/wp-content/uploads/2017/05/sandisk512.pngSandisk512https://thecavepearlproject.org/wp-content/uploads/2017/05/sandisktransflash128mb.pngSandiskTRANSflash128mbhttps://thecavepearlproject.org/wp-content/uploads/2017/05/nokia128mb.pngNokia128mbhttps://thecavepearlproject.org/wp-content/uploads/2017/05/kingmax128_wlabels1.pngKingmax128_wLabels2022-08-07T17:03:30+00:00monthlyhttps://thecavepearlproject.org/2019/02/25/no-parts-temperature-measurement-with-arduino-pro-mini-to-0-005c-or-better/https://thecavepearlproject.org/wp-content/uploads/2019/02/internaldiodejump-shift.jpgInternalDiodeJump-shifthttps://thecavepearlproject.org/wp-content/uploads/2019/02/internaldiode_256oversampled_variability-1.jpgInternalDiode_256oversampled_variabilitytesxthttps://thecavepearlproject.org/wp-content/uploads/2019/02/timer1_256x16mswdrinterval_variability.jpgTimer1_256x16msWDRinterval_variabilityraw variablhttps://thecavepearlproject.org/wp-content/uploads/2019/02/timer1_256x16ms_fit.jpgTimer1_256x16ms_fitcounthttps://thecavepearlproject.org/wp-content/uploads/2019/02/internaldiode_256oversampled_fiteq.jpgInternalDiode_256oversampled_fitEqcounthttps://thecavepearlproject.org/wp-content/uploads/2019/02/32khzreadingjittervswdtinterval.jpgCave Pearl data loggersReading Jitter during quiescent period, DS3231 32khz clock tics vs 4sec WDT intervalhttps://thecavepearlproject.org/wp-content/uploads/2019/02/ds323132khzticksvs4secwdtinterval.jpgCave Pearl data loggersDS3231 32khz clock ticks vs 4 second Watchdog timer intervalhttps://thecavepearlproject.org/wp-content/uploads/2019/02/2xaabatterythermalerror.jpg2xAAbatteryThermalErrorherehttps://thecavepearlproject.org/wp-content/uploads/2019/02/microsjitter.jpgMicrosJitterhttps://thecavepearlproject.org/wp-content/uploads/2019/02/2ndorderfit_wdttemp_prominiclone.jpgCave Pearl data loggers2nd order poly fitline for another unit using the Watchdog timer variation to determine temperature2022-01-28T22:18:10+00:00monthlyhttps://thecavepearlproject.org/2021/03/01/enhance-your-logger-with-an-oled-t233-capacitive-touch-switch/https://thecavepearlproject.org/wp-content/uploads/2021/03/ttp233_mountedinsidelogger.jpgCave Pearl data loggersUsing double sided tape to install a T233 capacitive touch switch inside the student build of the Cave Pearl DIY data loggerhttps://thecavepearlproject.org/wp-content/uploads/2021/03/ttp233_modifications_20210301.jpgCave Pearl data loggersSetting a T233 capacitive touch switch for Momentary LOW jumper, and removing the indicator LED for low power operation.https://thecavepearlproject.org/wp-content/uploads/2021/03/t233_trigersoleddisplay_20210301.jpgCave Pearl data loggersWith a t233 capactive touch switch, you can check the status of your cave pearl logger at any time.https://thecavepearlproject.org/wp-content/uploads/2021/03/oled_typicalscreenoutput.jpgCave Pearl data loggers2021-04-10T16:37:19+00:00monthlyhttps://thecavepearlproject.org/2018/10/17/tutorial-adding-a-ssd1306-oled-screen-to-your-arduino-logger/https://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_warduino_acrylicdiskprotectsscreen.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_oncavepearldatalogger.jpgCave Pearl data loggersSSD1306 OLED screen on a DIY Arduino Based Data loggerhttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_128x64oled.jpgCave Pearl data loggersSSD1306 OLED screenhttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_warduino_pt10_testafterexpoxy1.jpgSSD1306_OLED_wArduino_Pt10_TestAfterExpoxyhttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306oled_rc_delayedresetprovider.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_warduino_pt9_epoxyacrylicdisktoprotectdisplay.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_warduino_pt8_drilladdindicatorled.jpgCave Pearl data loggersAdding the SSD1306 OLED screen to your Arduino Data Logger: add hole in first layer of epoxy for indicator LEDhttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_warduino_pt7_add1stlayerpottingepoxy.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_warduino_pt6_testscreenb4epoxy.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2018/10/ssd1306_oled_warduino_pt5_spiconnections4shiftout.jpgCave Pearl data loggersAdding the SSD1306 OLED screen to your Arduino Data Logger: Connections for driving the OLED with shiftout using spare analog lines2021-03-18T20:44:44+00:00monthlyhttps://thecavepearlproject.org/2017/02/27/enhancing-arduinos-adc-resolution-by-dithering-oversampling/https://thecavepearlproject.org/wp-content/uploads/2017/02/ditheropamp.jpgDither&opamphttps://thecavepearlproject.org/wp-content/uploads/2017/02/failrun.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2017/02/caplossovertime.jpgCapLossOverTimehttps://thecavepearlproject.org/wp-content/uploads/2017/02/rctimeconstantscharging.jpgRCtimeConstants&Charginghttps://thecavepearlproject.org/wp-content/uploads/2017/02/oversamplinga100kthermistorwpintogglenoise.jpgCave Pearl data loggers15 bit equivalent oversampling of a 100k thermistor bridge with Edward Mallons pin toggling method used to genrerate dither noise.2021-02-18T20:06:20+00:00monthlyhttps://thecavepearlproject.org/2018/10/07/starting-points-ideas-for-an-arduino-stem-curriculum/https://thecavepearlproject.org/wp-content/uploads/2018/10/prepinglabkitsforarduinocourse_400x500px.jpgCave Pearl data loggersSetting up the Lab kits for an arduino based instrumentation course2021-01-27T02:27:15+00:00monthlyhttps://thecavepearlproject.org/2019/11/04/single-diode-temperature-sensor-with-arduino-icu-via-reverse-bias-leakage/https://thecavepearlproject.org/wp-content/uploads/2019/11/avriopincircuits.pngAVRioPinCircuitshttps://thecavepearlproject.org/wp-content/uploads/2019/11/1n4141diodeond7-8.jpgSingle Diode Temperature SensorFor most DIY purposes with an Arduino a reverse bias diode makes a better temperature sensor than a thermistor - and you can even use the same math!https://thecavepearlproject.org/wp-content/uploads/2019/11/arduinoiopinequivalentschematic.gifArduinoIOpinEquivalentSchematichttps://thecavepearlproject.org/wp-content/uploads/2019/11/diodeconnection.jpgDiodeConnectionhttps://thecavepearlproject.org/wp-content/uploads/2019/10/calibrationpointscomparison.jpgCave Pearl data loggersAccuracy of 1n1418 calculation based on location of calibration points used. Steinhart-Hart equation used on diode discharge.https://thecavepearlproject.org/wp-content/uploads/2019/10/srs_1n1418diodecalibration_640px.jpgSRS_1n1418DiodeCalibration_640pxused 20 reading averageshttps://thecavepearlproject.org/wp-content/uploads/2019/10/si7051referencetemperatures4calibration.jpgCave Pearl data loggerssi7051 Reference temperatures from calibration run with 1n1418 reverse bias dischargehttps://thecavepearlproject.org/wp-content/uploads/2019/10/signal_1n4148_reversebiasdischargetime-1.jpgCave Pearl data loggersTemperature (Celsius) vs 1n4148 reverse bias Leakage Discharge Time (Raw: 8 mHz clock cycles) This reverse bias self discharge time shows an exponential decay similar our LED light sensor experimentshttps://thecavepearlproject.org/wp-content/uploads/2019/10/shottky_1n5819_reversebiasdischargetime-1.jpgCave Pearl data loggersTemperature (Celsius) vs 1n5819 Shottky Leakage Discharge Time (Raw: 8 mHz clock cycles) This reverse bias self discharge time shows an exponential decay similar to the LED light sensor experiments.https://thecavepearlproject.org/wp-content/uploads/2019/10/shottky_pndiode.jpgShottky_PNdiode2021-01-26T18:49:35+00:00monthlyhttps://thecavepearlproject.org/2017/12/17/adding-sensors-to-an-arduino-data-logger/https://thecavepearlproject.org/wp-content/uploads/2017/12/pirsensor.jpgPIRsensorhttps://thecavepearlproject.org/wp-content/uploads/2017/12/ultrasonicsensor.jpgUltrasonicSensorhttps://thecavepearlproject.org/wp-content/uploads/2017/12/cavemicroclimaterecorder.jpgCave Pearl data loggersThis in-cave micro-climate recorder had pressure & temp. sensors mounted in little wells of Loctite E30-CL epoxy. This sensor potting method is described in the build tutorial HERE. Weather stations are the most popular kind of Arduino-based Sensor project found on the instructables website.https://thecavepearlproject.org/wp-content/uploads/2017/12/tsl235r.jpgTSL235Rhttps://thecavepearlproject.org/wp-content/uploads/2017/12/countvsmeasure1.pngCountVsMeasurehttps://thecavepearlproject.org/wp-content/uploads/2017/12/vdividerfromsparkfun.jpgVdividerFromSparkfunA typical photoresistor divider from Sparkfun's excellent Voltage Divider Tutorial.https://thecavepearlproject.org/wp-content/uploads/2017/12/sensorinterconnects.jpgCave Pearl data loggersThink about your sensor connections before you start your build. My current favorites are Deans Micro Plugs, which are available in 2,3,4,5,6,& 8 pin versionshttps://thecavepearlproject.org/wp-content/uploads/2017/12/grovei2chub.jpgCave Pearl data loggersThis Groove I2C hub joins all the bus wires, so only one jumper set gets passed down to the actual logger.https://thecavepearlproject.org/wp-content/uploads/2017/12/bulletproofswitchdebouncer.jpgBulletproofSwitchDebouncerA bullet-proof switch de-bouncer from www.ganssle.comhttps://thecavepearlproject.org/wp-content/uploads/2017/12/dstapemount.jpgDStapeMountThe quickest way to mount sensors inside a housing is with a couple of layers of double sided tape.2021-01-03T22:44:10+00:00monthlyhttps://thecavepearlproject.org/2016/10/27/diy-arduino-promini-data-logger-2016-build-update/https://thecavepearlproject.org/wp-content/uploads/2016/10/addingextraeeprom3.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2016/10/addingextraeeprom2.jpgAddingExtraEEprom2https://thecavepearlproject.org/wp-content/uploads/2016/10/addingextraeeprom.jpgAddingExtraEEpromhttps://thecavepearlproject.org/wp-content/uploads/2016/10/cavepearllogger_dupontjumpers_expanded1.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2016/10/cavepearllogger_dupontjumpers_expanded.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2016/10/36_led.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2016/10/36_ends.jpg36_endshttps://thecavepearlproject.org/wp-content/uploads/2016/10/34_powerconnector.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2016/10/33_powerrails3.jpgCave Pearl data loggershttps://thecavepearlproject.org/wp-content/uploads/2016/10/32_powerrails2.jpgCave Pearl data loggers2021-01-01T17:04:41+00:00monthlyhttps://thecavepearlproject.org/2016/08/08/build-your-own-arduino-classroom/https://thecavepearlproject.org/wp-content/uploads/2016/08/twistthepinsonpots.jpgTwistthePinsOnPotshttps://thecavepearlproject.org/wp-content/uploads/2016/08/ex330_100pix.jpgex330_100pixhttps://thecavepearlproject.org/wp-content/uploads/2016/08/30mwire_100px.jpg30Mwire_100pxhttps://thecavepearlproject.org/wp-content/uploads/2016/08/plano3440-10waterproofstowaway_100pix.jpgPlano3440-10WaterproofStowaway_100pixhttps://thecavepearlproject.org/wp-content/uploads/2016/08/planowatertightcase_100pxw.jpgPlanoWatertightCase_100pxwhttps://thecavepearlproject.org/wp-content/uploads/2016/08/wirespool_elenco.jpgwireSpool_elencohttps://thecavepearlproject.org/wp-content/uploads/2016/08/slimlinemultimeter.jpgSlimLineMultimeterhttps://thecavepearlproject.org/wp-content/uploads/2016/08/tiptinner.jpgTipTinnerhttps://thecavepearlproject.org/wp-content/uploads/2016/08/936solderironstand_100px.jpg936SolderIronStand_100pxhttps://thecavepearlproject.org/wp-content/uploads/2016/08/circuitvis.jpgCircuitVis2020-12-09T14:35:03+00:00monthlyhttps://thecavepearlproject.org/2020/05/11/build-an-atmega-1284p-based-data-logger/https://thecavepearlproject.org/wp-content/uploads/2020/05/protoboard1284_bydavecheney.jpgProtoboard1284_byDaveCheneyYou don't need much to turn a raw chip into something useable.Dave Cheney's protoboard build showshttps://thecavepearlproject.org/wp-content/uploads/2020/05/2650_board.jpg2650_boardhttps://thecavepearlproject.org/wp-content/uploads/2020/05/1284-27_addbreadboard-2.jpgCave Pearl data loggersMoteinoMEGA based Cave Pearl Logger with breadboard (2020-05-01)https://thecavepearlproject.org/wp-content/uploads/2020/05/1284-28_prototrim.jpgCave Pearl data loggers1284p MEGA based Cave Pearl in 'Prototyping Trim' with I2C OLED screen & ADS1115 ADC. INT1 & Aref jumperedhttps://thecavepearlproject.org/wp-content/uploads/2020/05/1284-27_addbreadboard.jpgCave Pearl data loggersCave Pearl Logger built using a Moteino MEGA with a1284p processor @ 16Mhz, 128KB program memory, 4KB internal EEPROM, 16KB SRAM for variables. More I/O pins than I know what to do with.https://thecavepearlproject.org/wp-content/uploads/2020/05/1284-26_rtc-4.jpgCave Pearl data loggersAlarm & I2C bus connectionshttps://thecavepearlproject.org/wp-content/uploads/2020/05/1284-24_rtc-2.jpgCave Pearl data loggerstwo pieces of DS foam tapehttps://thecavepearlproject.org/wp-content/uploads/2020/05/1284-23_rtc-1.jpgCave Pearl data loggersAdd 4 dupont pin headers, and attach jumper wires to the RTC modulehttps://thecavepearlproject.org/wp-content/uploads/2020/05/1284-22_twistwrapgnd.jpgCave Pearl data loggersNOW tape the MEGA/ST shield into the boxhttps://thecavepearlproject.org/wp-content/uploads/2020/05/1284-20_gndpwrconnections.jpgCave Pearl data loggersAttch GND wires before taping MEGA into the box2021-05-12T05:23:03+00:00monthlyhttps://thecavepearlproject.org/2016/03/05/ds18b20-calibration-we-finally-nailed-it/https://thecavepearlproject.org/wp-content/uploads/2016/03/slopeinterceptwithoutgraphing.jpgSlope&InterceptwithoutGraphinghttps://thecavepearlproject.org/wp-content/uploads/2016/03/calibrationsetup.jpgCave Pearl data loggersDS18b20 sensor calibration rig2020-11-30T04:52:10+00:00monthlyhttps://thecavepearlproject.org/2018/05/18/adding-the-nokia-5110-lcd-to-your-arduino-data-logger/https://thecavepearlproject.org/wp-content/uploads/2018/05/slideswitch.jpgSlideSwitchhttps://thecavepearlproject.org/wp-content/uploads/2018/05/downwardcollumns2.jpgDownwardcollumnshttps://thecavepearlproject.org/wp-content/uploads/2018/05/photocell.jpgPhotocellA photocell divider and a mosfet would let you enable the backlight depending on ambient conditions...https://thecavepearlproject.org/wp-content/uploads/2018/05/6pin-deans.jpg6pin-deansDeans micro-plugs are still my favorite connectors for multi-wire applications like this.https://thecavepearlproject.org/wp-content/uploads/2018/05/seawaterfoginstrumentscreen.jpgCave Pearl data loggersSeawater caused severe fogging of the potting epoxy after only 3 days of exposure.https://thecavepearlproject.org/wp-content/uploads/2018/05/n5110pressureburn.jpgCave Pearl data loggersContraction of the epoxy created a pressure burn on the LCD wiht a single monolithic pour.https://thecavepearlproject.org/wp-content/uploads/2018/05/nokia5110w4linesgnd.jpgCave Pearl data loggersConnecting a pin-powered nokia5110 screen to a cave pearl data logger, with 3 control lines and power from A0https://thecavepearlproject.org/wp-content/uploads/2018/05/epoxycreepsin2.jpgCave Pearl data loggersHere the backlight reflects off of the edgesof the epoxy that seeped into the screen before the epoxy finished curing.https://thecavepearlproject.org/wp-content/uploads/2018/05/epoxycreepsin.jpgCave Pearl data loggersHere the backlight shows the edges of the epoxy that seeped into the screen during the pottinghttps://thecavepearlproject.org/wp-content/uploads/2018/05/nokiascreenonclimatestation.jpgCave Pearl data loggersNokia5110 screen with a new BME280 climate logger2020-11-15T21:06:06+00:00monthlyhttps://thecavepearlproject.org/2019/01/11/pro-mini-logger-project-for-the-classroom-edu-version-2-2019/https://thecavepearlproject.org/wp-content/uploads/2019/01/siliconeoring_2.jpgSiliconeOring_2https://thecavepearlproject.org/wp-content/uploads/2019/01/siliconeoring_1.jpgSiliconeOring_1https://thecavepearlproject.org/wp-content/uploads/2019/01/plasticcableglandnowthreadsintohousing.jpgCave Pearl data loggersPlastic cable gland now threads into the housinghttps://thecavepearlproject.org/wp-content/uploads/2019/01/plasticcableglandnowthreadsintohousing-2.jpgCave Pearl data loggersPlastic Cable Gland Now Threads into the housinghttps://thecavepearlproject.org/wp-content/uploads/2019/01/removeringafteritcools.jpgCave Pearl data loggersAfter allowing to cool remove the metal threadshttps://thecavepearlproject.org/wp-content/uploads/2019/01/ringcutsintohousing1.jpgCave Pearl data loggersFloat configuration deploymnet on new housingshttps://thecavepearlproject.org/wp-content/uploads/2019/01/holdmetalring.jpgCave Pearl data loggersHold the metal threads in a pair of pliershttps://thecavepearlproject.org/wp-content/uploads/2019/01/matchingmetalplasticglands.jpgMatchingMetal&PlasticGlandshttps://thecavepearlproject.org/wp-content/uploads/2019/01/tiedownpoints2_640.jpgCave Pearl data loggersHoles for Zip Tie down pointshttps://thecavepearlproject.org/wp-content/uploads/2019/01/tiedownpoints1_640.jpgCave Pearl data loggersHoles for Zip Tie down points2020-10-28T21:44:18+00:00monthlyhttps://thecavepearlproject.org/2019/02/21/easy-1-hour-pro-mini-classroom-datalogger-build-update-feb-2019/https://thecavepearlproject.org/wp-content/uploads/2019/02/cleanedpartsstorage_withdessicants_640.jpgCleanedPartsStorage_withDessicants_640Old Nut containershttps://thecavepearlproject.org/wp-content/uploads/2019/02/improveo-ringseal_beforeafter.jpgCave Pearl data loggersBefore & After improving the O-ring sealhttps://thecavepearlproject.org/wp-content/uploads/2019/02/improveo-ringseal_addsilicone.jpgImproveO-ringSeal_AddSiliconehttps://thecavepearlproject.org/wp-content/uploads/2019/02/moistureaffectingledlightsensor.jpgCave Pearl data loggersGreen LED chanel as light level sensor - moisture condensing in box removed signal at start of the deployment.https://thecavepearlproject.org/wp-content/uploads/2019/02/7_tape-is-single-use.jpg7_tape is single usehttps://thecavepearlproject.org/wp-content/uploads/2019/02/6_after.jpgCave Pearl data loggersTape is single use due to sharp inner edge of lidhttps://thecavepearlproject.org/wp-content/uploads/2019/02/5_lidstillcloses.jpgCave Pearl data loggersLid closes to form a sealhttps://thecavepearlproject.org/wp-content/uploads/2019/02/4_redsurfaceontop.jpgCave Pearl data loggersFold the tape & wires over the corner edgehttps://thecavepearlproject.org/wp-content/uploads/2019/02/3_1-inch-square.jpgCave Pearl data loggersUse about a 1 inch square of the foam tapehttps://thecavepearlproject.org/wp-content/uploads/2019/02/2_30gaugewires.jpgCave Pearl data loggers30 gauge jumper wires long enough to reach edge of box2020-10-28T21:40:55+00:00monthlyhttps://thecavepearlproject.org/2015/10/24/diy-arduino-logger-build-instructions-part-1/https://thecavepearlproject.org/wp-content/uploads/2015/10/20180210_rocketloggerconnections_1240px.jpgCave Pearl data loggersDiagram modified from: Cave Pearl Data Logger: A Flexible Arduino-Based Logging Platform for Long-Term Monitoring in Harsh Environments Sensors 2018, 18(2), 530; doi:10.3390/s18020530 http://www.mdpi.com/1424-8220/18/2/530https://thecavepearlproject.org/wp-content/uploads/2015/10/20180210_promini_withcolorlines_1240px.png20180210_ProMini_withColorLines_1240px2020-10-23T19:03:25+00:00monthlyhttps://thecavepearlproject.org/2015/01/29/a-simple-diy-underwater-connector-system/https://thecavepearlproject.org/wp-content/uploads/2015/01/hullpassthroughsensormount_cavepearlproject.jpgCave Pearl data loggersHull pass-through and sensor mouting method for Cave Pearl Projects underwater data loggers. This DIY method is constructed from common PEX plumbing fittings.https://thecavepearlproject.org/wp-content/uploads/2015/01/beforeafterseating_640.jpgCave Pearl data loggersBefore&After heat treatment to seat the oringshttps://thecavepearlproject.org/wp-content/uploads/2015/01/presso-ringintoseat.jpgCave Pearl data loggersPress the oring onto the seat while the pvc is still warmhttps://thecavepearlproject.org/wp-content/uploads/2015/01/gentlyheattheseat.jpgCave Pearl data loggersHeating softens the rough seat and any casting spruehttps://thecavepearlproject.org/wp-content/uploads/2015/01/pressurerh_directconnect2housing.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Alternate hull pass through method with Pex connectors Developed by Edward Mallon & Dr. P. Beddowshttps://thecavepearlproject.org/wp-content/uploads/2015/01/insidecapwithdirectconnection2bulkhead.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Alternate hull pass-through method with Pex connectors Developed by Edward Mallon & Dr. P. Beddowshttps://thecavepearlproject.org/wp-content/uploads/2015/01/directconnectiontohousing.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Alternate hull pass through method with Pex connectors Developed by Edward Mallon & Dr. P. Beddowshttps://thecavepearlproject.org/wp-content/uploads/2015/01/capseam.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Alternate hull pass through method with Pex connectors Developed by Edward Mallon & Dr. P. Beddowshttps://thecavepearlproject.org/wp-content/uploads/2015/01/nibcoconnection.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Alternate hull pass-through method with Nibco Pex connectors Developed by Edward Mallon & Dr. P. Beddowshttps://thecavepearlproject.org/wp-content/uploads/2015/01/threadednptonbulkhead_600pxw.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Alternate hull pass through method with Nibco Pex connectors Developed by Edward Mallon & Dr. P. Beddows2020-06-19T15:16:57+00:00monthlyhttps://thecavepearlproject.org/2017/08/12/measuring-electrical-conductivity-with-an-arduino-part1-overview/https://thecavepearlproject.org/wp-content/uploads/2017/08/cn0349.jpgCN0349https://thecavepearlproject.org/wp-content/uploads/2017/08/vernierkit.jpgVernierKithttps://thecavepearlproject.org/wp-content/uploads/2017/08/conductivitysolutions.jpgconductivitySolutionshttps://thecavepearlproject.org/wp-content/uploads/2017/08/hannareplacementprobe.jpgHannaReplacementProbehttps://thecavepearlproject.org/wp-content/uploads/2017/08/ufireec.jpgUfireEChttps://thecavepearlproject.org/wp-content/uploads/2017/08/danscircuit.jpgDansCircuithttps://thecavepearlproject.org/wp-content/uploads/2017/08/probinopampfeedbackloop.jpgProbinOpampFeedbackLoophttps://thecavepearlproject.org/wp-content/uploads/2017/08/octavias-circuit.jpgOctavia's circuithttps://thecavepearlproject.org/wp-content/uploads/2017/08/petetrishwexo.jpgPete&TrishwExohttps://thecavepearlproject.org/wp-content/uploads/2017/08/ectempcoefficients.jpgECtempCoefficients2020-06-10T00:30:53+00:00monthlyhttps://thecavepearlproject.org/2017/06/19/arduino-data-logger-2017-build-update/https://thecavepearlproject.org/wp-content/uploads/2017/06/memmoduleschematic.jpgMemModuleSchematichttps://thecavepearlproject.org/wp-content/uploads/2017/06/eepromdippinouts.pngEEpromDipPinoutshttps://thecavepearlproject.org/wp-content/uploads/2017/06/ateepromcarrier_8addresses.jpgATeepromCarrier_8AddressesIf you can find DIP-8 chips, this carrier module lets you configure up to 8 I2C addresseshttps://thecavepearlproject.org/wp-content/uploads/2017/06/mcp1700spec.pngMCP1700specfig8https://thecavepearlproject.org/wp-content/uploads/2017/06/watinoprominipb.jpgWatinoProminiPBhttps://thecavepearlproject.org/wp-content/uploads/2017/06/backrowbreakout.jpgBackRowBreakouthttps://thecavepearlproject.org/wp-content/uploads/2017/06/a4-a7onbackrow.jpgA4-A7onBackRowhttps://thecavepearlproject.org/wp-content/uploads/2017/06/tripplepins2.jpgTripplePins2https://thecavepearlproject.org/wp-content/uploads/2017/06/tripplepins.jpgTripplePinshttps://thecavepearlproject.org/wp-content/uploads/2017/06/cavepearllogger_verticalmounting.jpgCave Pearl data loggersMounting the 2017 Screw Terminal build to a 2" test cap.2020-04-22T14:52:10+00:00monthlyhttps://thecavepearlproject.org/2015/02/04/a-new-diy-underwater-housing-for-2015/https://thecavepearlproject.org/wp-content/uploads/2015/02/pressurerh_directconnect2housing.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Alternate hull pass through method with Pex connectors Developed by Edward Mallon & Dr. P. Beddowshttps://thecavepearlproject.org/wp-content/uploads/2015/02/standardunderwaterbulkheadconnections.jpgCave Pearl data loggersCave Pearl Project: Housings: 2019 Standard hull pass through method with Nibco Pex connectors with pigtails potted in epoxy. Developed by Edward Mallon & Dr. P Beddows2020-04-08T18:11:32+00:00monthlyhttps://thecavepearlproject.org/2014/10/07/the-diy-data-logger-v2-with-low-power-shut-down-capability/2019-10-26T21:29:16+00:00monthlyhttps://thecavepearlproject.org/2016/08/15/using-the-arduino-uno-as-a-basic-data-acquisition-system/2019-09-30T23:10:10+00:00monthlyhttps://thecavepearlproject.org/2014/07/01/a-10-diy-data-logger-is-born/2019-09-22T16:02:10+00:00monthlyhttps://thecavepearlproject.org/2016/06/09/better-thermistor-readings-with-an-arduino-series-resistors-aref/2019-03-25T14:29:05+00:00monthlyhttps://thecavepearlproject.org/2018/01/02/the-2017-cave-pearl-project-year-in-review/https://thecavepearlproject.org/wp-content/uploads/2018/01/localcatsinvestigatelogger.jpgLocalCatsInvestigateLoggerhttps://thecavepearlproject.org/wp-content/uploads/2018/01/myfirstlogger.jpgCave Pearl data loggersMy first logger.https://thecavepearlproject.org/wp-content/uploads/2018/01/arduinosearchesfallinginus.jpgArduinoSearchesFallinginUShttps://thecavepearlproject.org/wp-content/uploads/2018/01/2017_blogtraffic.jpg2017_BlogTraffichttps://thecavepearlproject.org/wp-content/uploads/2018/01/crossedthe2yearmark1.jpgCrossedthe2YearmarkTypical Run times for Cave Pearl loggers without RTC pin power (0.25 mA) and with RTC pin powering (0.1mA)https://thecavepearlproject.org/wp-content/uploads/2018/01/encrusted1_310pix.jpgCave Pearl data loggersHeavy Bio encrustation on the estuary flow unitshttps://thecavepearlproject.org/wp-content/uploads/2018/01/imgp1007.jpgCave Pearl data loggersPressure Unit from Lagoon outflow after 6 month deploymenthttps://thecavepearlproject.org/wp-content/uploads/2018/01/imgp0759.jpgCave Pearl data loggersBio fouling on estuary flow unit in 6 monthshttps://thecavepearlproject.org/wp-content/uploads/2018/01/imgp0751.jpgCave Pearl data loggersHeavy bio growth on units deployed in an estuaryhttps://thecavepearlproject.org/wp-content/uploads/2018/01/hsulfidelogger.jpgCave Pearl data loggersSponges growing on a flow logger after a two year deployment in a hydrogen sulfide rich cave.2019-03-09T22:17:17+00:00monthlyhttps://thecavepearlproject.org/2018/08/24/tutorial-using-the-arduinos-internal-eeprom-for-fonts-header-data/https://thecavepearlproject.org/wp-content/uploads/2018/08/24bytesleft.jpg24BytesLeft2019-02-01T20:27:41+00:00monthlyhttps://thecavepearlproject.org/2015/12/22/arduino-uno-based-data-logger-with-no-soldering/https://thecavepearlproject.org/wp-content/uploads/2015/12/tlpboard.jpgTLPboardIn late 2017 Adafruit released a TPL5110 breakout board that provides a fantastic low power option for UNO based projects, enabling you to get down to 30 micro Amp sleep between readings!2018-12-18T17:22:58+00:00monthlyhttps://thecavepearlproject.org/2016/05/01/field-report-2016-03-27-progress-on-the-ds18b20-temp-strings/2018-12-04T22:08:43+00:00monthlyhttps://thecavepearlproject.org/2017/01/07/the-2016-cave-pearl-project-year-in-review/2018-10-11T18:33:45+00:00monthlyhttps://thecavepearlproject.org/2017/11/27/bil-a-phillips-an-explorer-a-teacher-and-a-friend/https://thecavepearlproject.org/wp-content/uploads/2017/11/billcruzin_600px.jpgBillCruzin_600pxhttps://thecavepearlproject.org/wp-content/uploads/2017/11/bilaphillips_onexpedition.jpgBilAPhillips_onExpeditionPhoto from the 2010 National Geographic funded expedition to explore the Sacred pools of Cara Blanca, in Belize.2018-10-11T18:12:22+00:00monthlyhttps://thecavepearlproject.org/2014/09/22/high-sleep-current-problem-solved/2018-10-11T15:34:46+00:00monthlyhttps://thecavepearlproject.org/2016/02/12/triage-step-for-cheap-ds18b20-temperature-sensors/2018-10-07T15:44:47+00:00monthlyhttps://thecavepearlproject.org/2014/02/07/project-update-dec-1-2013/2018-10-07T15:39:07+00:00monthlyhttps://thecavepearlproject.org/2014/02/19/whats-running-in-the-currently-deployed-prototypes/2018-10-07T15:36:57+00:00monthlyhttps://thecavepearlproject.org/2014/03/03/buffering-sensor-data-to-an-i2c-eeprom/2018-10-07T15:35:50+00:00monthlyhttps://thecavepearlproject.org/2014/03/12/using-a-ds18b20-temp-sensor-without-a-dedicated-library/2018-10-07T15:31:37+00:00monthlyhttps://thecavepearlproject.org/2014/09/18/field-report-2014-08-24-assemble-test-all-units/2018-10-07T15:30:45+00:00monthlyhttps://thecavepearlproject.org/2015/01/07/field-report-2014-12-12-retrieve-the-costal-discharge-sensors/2018-10-07T15:29:11+00:00monthlyhttps://thecavepearlproject.org/2015/10/24/diy-arduino-logger-build-instructions-part-3/2018-10-06T16:32:51+00:00monthlyhttps://thecavepearlproject.org/2015/10/24/diy-arduino-logger-build-instructions-part-2/2018-10-06T16:32:01+00:00monthlyhttps://thecavepearlproject.org/2015/11/05/a-diy-arduino-data-logger-build-instructions-part-4-power-optimization/2018-10-06T16:31:16+00:00monthlyhttps://thecavepearlproject.org/2014/10/06/what-to-expect-when-buying-cheap-electronic-components/2018-10-06T16:03:20+00:00monthlyhttps://thecavepearlproject.org/2015/01/16/field-report-2014-12-18-a-flow-sensor-co-deployment/2018-10-06T15:54:25+00:00monthlyhttps://thecavepearlproject.org/2015/06/28/testing-power-use-with-a-complex-duty-cycle/2018-10-06T15:49:32+00:00monthlyhttps://thecavepearlproject.org/2015/08/26/field-report-2015-08-10-diagnosing-a-tmp102-temp-sensor-failure/2018-10-06T15:48:26+00:00monthlyhttps://thecavepearlproject.org/2015/09/03/how-the-drag-enhancer-affected-flow-meter-response/2018-10-06T15:47:50+00:00monthlyhttps://thecavepearlproject.org/2016/01/05/field-report-2015-12-08-rain-gauge-success-at-rio-secreto/2018-10-06T15:44:39+00:00monthlyhttps://thecavepearlproject.org/2016/01/20/another-look-at-battery-discharge-curves/2018-10-06T15:43:33+00:00monthlyhttps://thecavepearlproject.org/2016/04/19/field-report-2016-03-25-monitoring-in-coastal-mangroves/https://thecavepearlproject.org/wp-content/uploads/2016/04/trishboatcaptainwflowsensor_2017.jpgCave Pearl data loggersDr Beddows examines a heavily encrusted flow sensor after a 1 year estuarine deployment2018-10-06T15:38:38+00:00monthlyhttps://thecavepearlproject.org/2015/08/26/field-report-2015-08-12-success-with-ds18b20-temperature-strings/2018-10-06T00:52:21+00:00monthlyhttps://thecavepearlproject.org/2016/01/07/field-report-2015-12-10-precision-vs-accuracy-again/2018-10-06T00:46:10+00:00monthlyhttps://thecavepearlproject.org/2016/04/06/field-report-2016-03-17-mcp9808-fails-under-pressure/2018-10-06T00:44:54+00:00monthlyhttps://thecavepearlproject.org/2014/03/19/the-new-fleet-is-ready-to-sail/2018-10-06T00:44:03+00:00monthlyhttps://thecavepearlproject.org/2016/01/10/field-report-2015-12-15-new-ds18b20-sensor-chains-installed/2018-10-05T23:32:16+00:00monthlyhttps://thecavepearlproject.org/2015/07/08/measuring-humidity-in-a-cave-a-masons-hyrgometer-experiment/2018-10-05T05:04:04+00:00monthlyhttps://thecavepearlproject.org/2016/09/21/field-report-2016-07-09-i2c-pressure-sensors-work-on-20m-cables/2018-10-05T04:58:03+00:00monthlyhttps://thecavepearlproject.org/2016/05/11/field-report-2016-03-28-oldest-generation-of-loggers-retired/2018-01-18T18:38:40+00:00monthlyhttps://thecavepearlproject.org/2016/04/05/field-report-2016-03-16-rain-gauges-over-reporting/2018-01-18T18:35:57+00:00monthlyhttps://thecavepearlproject.org/2016/01/13/field-report-2015-12-20-winding-down/2018-01-18T18:35:07+00:00monthlyhttps://thecavepearlproject.org/2016/01/10/field-report-2015-12-14-re-install-the-drip-monitoring-network/2018-01-18T18:33:39+00:00monthlyhttps://thecavepearlproject.org/2016/01/09/field-report-2015-12-11-flow-sensors-go-farther-deeper/2018-01-18T18:32:50+00:00monthlyhttps://thecavepearlproject.org/2015/11/08/cave-pearl-loggers-presented-at-gsa-2015/2018-01-18T18:30:31+00:00monthlyhttps://thecavepearlproject.org/2015/09/20/interview-video-2015-09-20/2018-01-18T18:29:47+00:00monthlyhttps://thecavepearlproject.org/2015/09/02/field-report-2015-08-17-flow-sensors-go-back-into-akumal-bay/2018-01-18T18:28:54+00:00monthlyhttps://thecavepearlproject.org/2015/08/31/field-report-2015-08-14-install-new-sensors-at-riosecreto/2018-01-18T18:28:11+00:00monthlyhttps://thecavepearlproject.org/2015/08/24/field-report-2015-08-07-retrieve-logger-from-akumal-bay/2018-01-18T18:23:37+00:00monthlyhttps://thecavepearlproject.org/2015/08/21/field-report-2015-08-06-retrieve-sensors-from-riosecreto/2018-01-18T18:23:03+00:00monthlyhttps://thecavepearlproject.org/2015/04/20/field-report-2015-03-23-flow-sensor-drag-fins-tested/2018-01-18T18:22:06+00:00monthlyhttps://thecavepearlproject.org/2015/04/15/field-report-2015-03-18-one-logger-sacrificed-to-the-sea-gods/2018-01-18T18:21:18+00:00monthlyhttps://thecavepearlproject.org/2015/04/11/field-report-2015-03-17-drip-logger-service-visit/2018-01-18T18:20:31+00:00monthlyhttps://thecavepearlproject.org/2015/01/18/field-report-2014-12-20-drip-sensor-deployment-at-rio-secreto/https://thecavepearlproject.org/wp-content/uploads/2015/01/takingmanualdripcounts.jpgCounting dripsHere Aubrey and Ben are timing drips at a typical cluster.https://thecavepearlproject.org/wp-content/uploads/2015/01/rhsensor_underaledge.jpgPressure, RH & temp sensorHopefully the ledge will give some measure of protectionhttps://thecavepearlproject.org/wp-content/uploads/2015/01/benedfernaubrey.jpgBen, Ed, Fernanda and AubreyBen Schwartz, Edward Mallon, Fernanda Lasas, Aubrey Xhttps://thecavepearlproject.org/wp-content/uploads/2015/01/preparingtoinstalldsensors.jpgPreparingToInstallDSensorsOne stayed on the surface as a rough rain gauge.2018-01-18T18:17:51+00:00monthlyhttps://thecavepearlproject.org/2015/01/28/the-2014-cave-pearl-project-year-in-review/https://thecavepearlproject.org/wp-content/uploads/2015/01/cavepearlsdeployed_2014.jpgCave Pearl DIY housings made from PVChttps://thecavepearlproject.org/wp-content/uploads/2015/01/cavepearlblog_toppages.jpgCavePearlBlog_TopPageshttps://thecavepearlproject.org/wp-content/uploads/2015/01/cavepearlblog_typicalweeklytraffic.jpgCavePearlBlog_TypicalWeeklyTraffichttps://thecavepearlproject.org/wp-content/uploads/2015/01/cavepearlblogtraffic_2014.jpgCavePearlBlogTraffic_2014https://thecavepearlproject.org/wp-content/uploads/2015/01/physical-build-tryptic_2014.jpgCave Pearl Physical Build Tryptichttps://thecavepearlproject.org/wp-content/uploads/2015/01/platform_tryptic_jan2014.jpgPlatform_tryptic_Jan20142018-01-18T18:16:26+00:00monthlyhttps://thecavepearlproject.org/2015/01/09/field-report-2014-12-16-rebuilding-reloading-the-old-sensors/https://thecavepearlproject.org/wp-content/uploads/2015/01/20141214_thefieldstation.jpg20141214_theFieldStationThe depth limits on our point & shoot camera prevented us from capturing photos from the dives. But a pile of 1st & 2nd gen units was slowly accumulating on the floor in our room...https://thecavepearlproject.org/wp-content/uploads/2015/01/sealingupthehull.jpgSealingUpTheHullGood enough for a "surface" deploymenthttps://thecavepearlproject.org/wp-content/uploads/2015/01/refurbtestruns.jpgRefurbTestRunsEach rebuilt unit needed a 24 hour test run...https://thecavepearlproject.org/wp-content/uploads/2015/01/oldunitstorefurbish.jpgOldUnitstoRefurbishI don't have photographs of these "exchange" dives, as they all exceeded the maximum depth of our little point and shoot camera.2018-01-18T18:12:33+00:00monthlyhttps://thecavepearlproject.org/2015/01/06/field-report-2014-12-11-our-first-real-world-drip-sensor-data/https://thecavepearlproject.org/wp-content/uploads/2015/01/dripsensorpowercurves.jpgBattery Voltage vs Sleep Currenthttps://thecavepearlproject.org/wp-content/uploads/2015/01/unit7_rs_aug20141.jpgDripSensor07_Data_RioSecreto_Aug-Dec_2014https://thecavepearlproject.org/wp-content/uploads/2015/01/ds01_augustdeploymentdata1.jpgCave Pearl Drip Sensor DATAhttps://thecavepearlproject.org/wp-content/uploads/2015/01/unit7.jpgUnit7Our deployment sites were within site of survey stations, so we could triangulate surface locations later.2018-01-18T18:10:18+00:00monthlyhttps://thecavepearlproject.org/2015/01/05/field-report-2014-12-10-retrieval-of-the-salt-water-pearls/https://thecavepearlproject.org/wp-content/uploads/2015/01/akumalbay_unitb4_temprecord1.jpgAkumalBay_unitB4_TempRecordhttps://thecavepearlproject.org/wp-content/uploads/2015/01/stowaway2.jpgStowAway2We had a little farmer tending the crop on unit3.https://thecavepearlproject.org/wp-content/uploads/2015/01/loctiteyellowing.jpgLoctiteYellowinghttps://thecavepearlproject.org/wp-content/uploads/2015/01/jbweld.jpgJbweldhttps://thecavepearlproject.org/wp-content/uploads/2015/01/b4_cea_clock-drift-check.jpgB4_cea_clock drift checkhttps://thecavepearlproject.org/wp-content/uploads/2015/01/b4_battery.jpgB4_Batteryhttps://thecavepearlproject.org/wp-content/uploads/2015/01/colorfulgrowth.jpgColorfulGrowthThe Oring seats were still clear. I guess PVC tastes better than EPDM?https://thecavepearlproject.org/wp-content/uploads/2015/01/cabletiefail.jpgCableTieFailThe connection rods now use a combination of several cable ties.https://thecavepearlproject.org/wp-content/uploads/2015/01/seriousbiofilm2_500px.jpgSeriousBioFilm2_500pxThere was even a few small crabs crawling around on the surface.https://thecavepearlproject.org/wp-content/uploads/2015/01/cuttingthebasefree.jpgCuttingTheBaseFreeWe did not have scuba gear, so the fastest approach was simply to cut the anchors away.2018-01-18T18:08:47+00:00monthlyhttps://thecavepearlproject.org/2015/01/05/project-update-gearing-up-for-field-work-2014-11-26/https://thecavepearlproject.org/wp-content/uploads/2015/01/flowsensorshangtest.jpgCave Pear Flow SensorsYou need at least a week of dry runs, as some sensors fail after a few days of operation.https://thecavepearlproject.org/wp-content/uploads/2015/01/nov2014_cavepearlflowsensor.jpgCave Pearl Flow Sensorhttps://thecavepearlproject.org/wp-content/uploads/2015/01/next-generation-of-sensor-caps.jpgCavePearlFlowMeter CapsUsing Loctite E00-CL this time round.2018-01-18T18:07:20+00:00monthlyhttps://thecavepearlproject.org/2014/12/01/project-update-the-next-generation-of-drip-sensors/https://thecavepearlproject.org/wp-content/uploads/2014/11/heatshrinktubingnozzle.jpgDrip Nozzle with heat shrink tubingI used heat-shrink to get nice sharp 5mm diameter tube tip.https://thecavepearlproject.org/wp-content/uploads/2014/11/surfacesplatter.jpgSurfaceSplatterSurface splatter from a drip impact. The green light is the LED indicating the count.https://thecavepearlproject.org/wp-content/uploads/2014/11/cavepearldripsensor_testrig.jpgDrip sensor test righttps://thecavepearlproject.org/wp-content/uploads/2014/11/unit3_rios_powercurvegraph_201400726-1010.jpgUnit3_RioS_PowerCurveGraph_201400726-1010https://thecavepearlproject.org/wp-content/uploads/2014/11/directpinpowerrtc.jpgDirectPinPowerRTCWhen you disconnect Vcc, the DS3231 goes into a 3uA timekeeping mode.https://thecavepearlproject.org/wp-content/uploads/2014/11/lowestsleepcurrentyet.jpgCave Pearl Drip Sensor Data Logger2018-01-18T18:05:08+00:00monthlyhttps://thecavepearlproject.org/2014/10/31/cave-pearls-presented-at-the-geological-society-of-america-conference/https://thecavepearlproject.org/wp-content/uploads/2014/10/trish_explainsflowsensor.jpgGSA2014_presenting the flow sensorsTrish describing the flow sensor deploymentshttps://thecavepearlproject.org/wp-content/uploads/2014/10/lineup_300px.jpglineup_300pxHaving a lineup before you even finish setting up the poster in the morning is always a good sign...2018-01-18T18:03:29+00:00monthlyhttps://thecavepearlproject.org/read-the-blog/2017-11-23T06:37:08+00:00weekly0.6https://thecavepearlproject.org/2014/02/02/in-the-beginning-part-3/https://thecavepearlproject.org/wp-content/uploads/2014/02/johnson-air-speed-indicator.jpgPressure deflectionThe Johnson Air speed indicator (1935)2017-01-24T19:26:12+00:00monthlyhttps://thecavepearlproject.org/2014/06/16/github-launch-for-the-cave-pearl-project/2016-06-30T05:14:39+00:00monthlyhttps://thecavepearlproject.org/2014/07/25/more-lessons-learned-along-the-way/https://thecavepearlproject.org/wp-content/uploads/2014/07/longleft_shortright.jpgLongLeft_ShortRightLeft side: Loctite Nozzle Right Side: Short Generic Nozzlehttps://thecavepearlproject.org/wp-content/uploads/2014/07/topcheap_bottomloctite.jpgTopCheap_BottomLoctitehttps://thecavepearlproject.org/wp-content/uploads/2014/07/solderingpins.jpgSolderingPinsMany thanks to my bother Mike for showing me this soldering technique!https://thecavepearlproject.org/wp-content/uploads/2014/07/bigiron1.jpgBigIronhttps://thecavepearlproject.org/wp-content/uploads/2014/07/prototyping.jpgPrototypingOnly RTC & interrupt lines get soldered to the mcu.https://thecavepearlproject.org/wp-content/uploads/2014/07/doa_adxl345.jpgDOA_adxl345More than a few of the cheap eBay boards are D.O.A.https://thecavepearlproject.org/wp-content/uploads/2014/07/benchvice.jpgBenchviceThis type of bench vise is worth finding. I picked this used one up for $10, and it has been fantastic for holding parts together while epoxies cure & solvents weld PVC parts.2016-03-13T20:18:42+00:00monthlyhttps://thecavepearlproject.org/2014/07/15/a-new-sensor-for-cave-research/https://thecavepearlproject.org/wp-content/uploads/2014/07/removingvregulatorfromadxl345.jpgRemovingVRegulatorfromADXL345Mods to the ADXL345 on a regulated bus.https://thecavepearlproject.org/wp-content/uploads/2014/07/dripsensorbeta.jpgDripSensorBetahttps://thecavepearlproject.org/wp-content/uploads/2014/07/trishinstallssensor2_2004.jpgTrishInstallsSensor2_2004DIY cave water sensors (2004)2016-01-11T19:21:07+00:00monthlyhttps://thecavepearlproject.org/2014/06/17/using-a-tmp102-i2c-temperature-sensor/https://thecavepearlproject.org/wp-content/uploads/2014/06/dont-do-float-calculations-on-arduino.jpgDont do float Calculations on ARDUINOhttps://thecavepearlproject.org/wp-content/uploads/2014/06/tmp102.jpgTMP102Note: SDA and SCL pullup resistors have been removed.2015-10-22T16:22:39+00:00monthlyhttps://thecavepearlproject.org/2014/01/31/in-the-beginning-part-2/https://thecavepearlproject.org/wp-content/uploads/2014/01/trishinstallssensor_2004.jpgTrishInstallsSensor_2004Trish connecting one of our home made drip sensors.https://thecavepearlproject.org/wp-content/uploads/2014/01/s4-on-tripod-at-cenote.jpgS4 on tripod at cenoteS4 ready to deploy in the cave.https://thecavepearlproject.org/wp-content/uploads/2014/01/9943-wireing-up-boards2.jpg9943 wireing up boards2Trish wiring up our home made drip sensors in 2004https://thecavepearlproject.org/wp-content/uploads/2014/01/trish-working-on-rcm.jpgTrish working on RCMTrish doing field repairs.https://thecavepearlproject.org/wp-content/uploads/2014/01/failed-oring-on-rcm.jpgFailed Oring on RCMAnother O-ring failure.https://thecavepearlproject.org/wp-content/uploads/2014/01/rcm-on-lift-bag2.jpgRcm on lift bag2It took a lift bag just to move the RCM units.https://thecavepearlproject.org/wp-content/uploads/2014/01/swiming-with-the-ott-hydrometer.jpgDiving with the OTTDiving with the OTThttps://thecavepearlproject.org/wp-content/uploads/2014/01/trish-with-her-toys2.jpgTrish with RCM7 & OTTTrish with RCM7 & OTT2015-07-21T14:54:04+00:00monthlyhttps://thecavepearlproject.org/2014/06/13/using-a-bma180-accelerometer-as-a-high-resolution-tilt-sensor/https://thecavepearlproject.org/wp-content/uploads/2014/06/bma180connections.jpgBMA180connectionshttps://thecavepearlproject.org/wp-content/uploads/2014/06/bma180-output1.jpgBMA180 outputNote: the sensor was not level here, just hanging on some wires.https://thecavepearlproject.org/wp-content/uploads/2014/06/bma180.jpgBMA180I know you are supposed to decouple Vcc and Vdd, but I have not figured out how to do that yet.2015-07-01T19:48:51+00:00monthlyhttps://thecavepearlproject.org/2014/02/05/switching-to-a-low-power-platform/https://thecavepearlproject.org/wp-content/uploads/2014/02/alpha-vs-beta.jpgAlpha VS Beta2015-07-01T15:38:36+00:00monthlyhttps://thecavepearlproject.org/2014/12/16/sleeping-an-mcp9808-on-a-pressure-rh-temp-logger/https://thecavepearlproject.org/wp-content/uploads/2014/12/epoxypluggedsensor0.jpgDIY Cave Pearl data loggers based on Arduino MicrocontrollersNew pivot joint for the open ocean units.https://thecavepearlproject.org/wp-content/uploads/2014/12/carefullyepoxytheprotectivecap.jpgCarefullyEpoxytheProtectiveCaphttps://thecavepearlproject.org/wp-content/uploads/2014/12/cableroutingonpressrhtempsensor.jpgCableRoutingonPressRH&TempSensorGood old JB plastiweld lets me tuck the Groove hub up out of the way, as all the real estate on my platform is taken up with the battery holders.https://thecavepearlproject.org/wp-content/uploads/2014/12/holdingsensorlevelwhileepxoysets.jpgHoldingSensorLevelwhileEpxoySets The wires of the housing pass-through always push the boards into odd angles, so I level the boards with a preliminary 'underlayer" of cured epoxy while applying some top pressure with a pin to hold things in placehttps://thecavepearlproject.org/wp-content/uploads/2014/12/cavepearl_pressurerh_sensor.jpgCavePearl_Pressure&RH_sensorLeft: MS5805-02, HTU, MCP9808 Right: MS5803-02, HTU ,TMP1022015-06-26T17:27:00+00:00monthlyhttps://thecavepearlproject.org/2014/02/07/the-full-monty-dec-3-2013/https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0314.jpgIMGP0314Trish ties off Unit 12015-06-01T16:57:24+00:00monthlyhttps://thecavepearlproject.org/2014/08/22/more-duracell-battery-failures-this-week/https://thecavepearlproject.org/wp-content/uploads/2014/08/thesecondfailure_closeup.jpgTheSecondFailure_closeupThe other leak this weekhttps://thecavepearlproject.org/wp-content/uploads/2014/08/voltageduringbatteryfail.jpgVoltageduringBatteryFailhttps://thecavepearlproject.org/wp-content/uploads/2014/08/the3rdduracellfailure.jpgThe3rdDuracellFailureThe dead power modulehttps://thecavepearlproject.org/wp-content/uploads/2014/08/hangingtest.jpgThe Cave Pearl - a hydrometric pendulumHouston we have a problem...2015-05-14T19:11:29+00:00monthlyhttps://thecavepearlproject.org/2014/02/03/background-research-for-the-housing/https://thecavepearlproject.org/wp-content/uploads/2014/02/otterlight.jpgOtterlighthttps://thecavepearlproject.org/wp-content/uploads/2014/02/flat-stock.jpgflat stockhttps://thecavepearlproject.org/wp-content/uploads/2014/02/submarine.jpgsubmarinehttps://thecavepearlproject.org/wp-content/uploads/2014/02/redcam.jpgRedCam2015-05-02T05:12:09+00:00monthlyhttps://thecavepearlproject.org/2014/09/21/bench-testing-vs-reality/https://thecavepearlproject.org/wp-content/uploads/2014/09/ms5803_projection.jpgMS5803_projectionhttps://thecavepearlproject.org/wp-content/uploads/2014/09/benchtest_against-time.jpgBenchTest_against timehttps://thecavepearlproject.org/wp-content/uploads/2014/09/units34_compare_6401.jpgUnits3&4_compare_640https://thecavepearlproject.org/wp-content/uploads/2014/09/unit3_projection.jpgUnit3_projectionhttps://thecavepearlproject.org/wp-content/uploads/2014/09/unit4_projection.jpgUnit4_projection2015-04-15T16:26:25+00:00monthlyhttps://thecavepearlproject.org/2014/09/19/field-report-2014-09-02-our-first-open-water-deployment/https://thecavepearlproject.org/wp-content/uploads/2014/09/unit4_anchoredinakumal.jpgUnit4_AnchoredinAkumalHopefully secure enough from boats, waves and tourists.https://thecavepearlproject.org/wp-content/uploads/2014/09/markoeddeployunit4.jpgMarko&EdDeployUnit4Installing the sensorhttps://thecavepearlproject.org/wp-content/uploads/2014/09/markoedbeforedive.jpgMarko&EdBeforeDiveShowing Marco from CEA how the support system works.2015-04-15T16:07:31+00:00monthlyhttps://thecavepearlproject.org/2014/09/19/field-report-2014-08-26-old-flow-sensor-inspection/https://thecavepearlproject.org/wp-content/uploads/2014/09/jbmarine-weld.jpgjbmarine weldSome pitting on the JB weld surface.https://thecavepearlproject.org/wp-content/uploads/2014/09/e30cl.jpge30clStill clear, and nothing growing on the surface.https://thecavepearlproject.org/wp-content/uploads/2014/09/9-differences.jpg9-differencesFrom the same batch?2015-04-15T16:06:45+00:00monthlyhttps://thecavepearlproject.org/2014/09/19/field-report-2014-09-01-our-first-deep-saline-installation/https://thecavepearlproject.org/wp-content/uploads/2014/09/calibratingbuoyancy21.jpgCalibratingBuoyancy2Did I mention how much I dislike tábanos?2015-04-15T16:06:08+00:00monthlyhttps://thecavepearlproject.org/2014/09/18/field-report-2014-08-25-retrieve-deploy-flow-sensors/https://thecavepearlproject.org/wp-content/uploads/2014/09/6-lotsofperc.jpg6-LotsofPercLots of percolation in this systemhttps://thecavepearlproject.org/wp-content/uploads/2014/09/edtrish_examinebetaunits.jpgED&Trish_ExamineBetaUnitsI think there is an ocean and a sunset in this picture. But at the time, we did not even notice it.https://thecavepearlproject.org/wp-content/uploads/2014/09/5-oldvsnew.jpg5-oldVSnewOld vs. Newhttps://thecavepearlproject.org/wp-content/uploads/2014/09/3b_inspecttheoldunits.jpg3b_inspectTheOldUnitsChecking for rotation, damage, etc.https://thecavepearlproject.org/wp-content/uploads/2014/09/pickingupgear.jpgPickingUpGearPre-dive planning with Bill, Trish, Monica & Jeff.2015-04-15T16:05:40+00:00monthlyhttps://thecavepearlproject.org/2014/09/18/gearing-up-for-field-work/https://thecavepearlproject.org/wp-content/uploads/2014/09/ds_300pix.jpgDS_300pixSimilar to one of the early flow meters, this would probably withstand submersion for quite a while.https://thecavepearlproject.org/wp-content/uploads/2014/09/rosettastone1.jpgRosettaStone1https://thecavepearlproject.org/wp-content/uploads/2014/09/gluingsensors.jpgGluingSensorshttps://thecavepearlproject.org/wp-content/uploads/2014/09/packedready2.jpgPacked&Ready2Packed & Ready to go..2015-04-15T16:05:05+00:00monthlyhttps://thecavepearlproject.org/2014/03/24/the-next-generation-of-loggers-is-deployed/https://thecavepearlproject.org/wp-content/uploads/2014/03/img_6120_onthebench.jpgIMG_6120_onthebenchAs usual, we had one unit misbehave on the bench so badly it needed a complete "brain transplant". https://thecavepearlproject.org/wp-content/uploads/2014/03/field-testing-station.jpgfield Testing stationThe Field Testing Station.https://thecavepearlproject.org/wp-content/uploads/2014/03/img_6230-mod.jpgIMG_6230-modA Reef census is co-deployed with the pressure sensor to ground truth this initial test.https://thecavepearlproject.org/wp-content/uploads/2014/03/calibratingbuoyancy1.jpgCalibratingBuoyancy1I used the deflection of an 8 inch cable tie as a rough field balance. Units were tuned to approximately 10-20 grams negative.https://thecavepearlproject.org/wp-content/uploads/2014/03/codeploy.jpgCoDeployThey are deployed quite close together, to allow me to assess inter-unit response for this build.2015-04-15T16:03:56+00:00monthlyhttps://thecavepearlproject.org/2014/03/20/the-cave-pearls-have-landed/https://thecavepearlproject.org/wp-content/uploads/2014/03/ed-with-two-units1.jpgEd with two unitsAbout to surface with the beta loggers.https://thecavepearlproject.org/wp-content/uploads/2014/03/suitcasefullofsensors.jpgSuitcaseFullOfSensorsI am still amazed that all this makes it through the airport scanners...https://thecavepearlproject.org/wp-content/uploads/2014/03/zcomparebase_range_650pix-label.jpgZcompareBase_Range_650pix-labelLeft: Unit1 Right:Unit2 Raw z Axis, sub-samplehttps://thecavepearlproject.org/wp-content/uploads/2014/03/breaking-the-seal.jpgBreaking the SealBreaking the seal.https://thecavepearlproject.org/wp-content/uploads/2014/03/mvrecord_600pix.jpgMVRecord_600pixLeft: Unit 1 Right: Unit 2 (rubber bottom)https://thecavepearlproject.org/wp-content/uploads/2014/03/happyed.jpghappyEdNot flooded!https://thecavepearlproject.org/wp-content/uploads/2014/03/img_6113.jpgIMG_6113https://thecavepearlproject.org/wp-content/uploads/2014/03/awaiting-deployment.jpgawaiting deploymenthttps://thecavepearlproject.org/wp-content/uploads/2014/03/two-units-ready-to-open.jpgTwo units ready to open2015-04-15T16:01:53+00:00monthlyhttps://thecavepearlproject.org/2014/02/09/final-deployment-dec-16-2013/https://thecavepearlproject.org/wp-content/uploads/2014/02/dec16_longdeploymentmascot.jpgDec16_longDeploymentMascot2015-04-15T16:01:02+00:00monthlyhttps://thecavepearlproject.org/2014/02/08/the-moment-of-truth-dec-6-2013/https://thecavepearlproject.org/wp-content/uploads/2014/02/datafrom1stdeployment_640.jpgDataFrom1stDeployment_6403 days of raw data from the very first deployment.https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp04721.jpgIMGP0472https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0472.jpgIMGP0472Retrieval after first deployment.2015-04-15T16:00:32+00:00monthlyhttps://thecavepearlproject.org/2014/02/07/project-update-nov-30-2013/https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0172.jpgIMGP0172https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0171.jpgIMGP01712015-04-15T15:58:50+00:00monthlyhttps://thecavepearlproject.org/2014/02/05/a-note-on-using-the-tinyduino-platform/https://thecavepearlproject.org/wp-content/uploads/2014/02/igp9129.jpg_IGP9129https://thecavepearlproject.org/wp-content/uploads/2014/02/igp9121.jpg_IGP9121https://thecavepearlproject.org/wp-content/uploads/2014/02/chrondot.jpgchrondot2015-04-15T15:27:04+00:00monthlyhttps://thecavepearlproject.org/2014/01/29/were-to-begin/https://thecavepearlproject.org/wp-content/uploads/2014/01/alltherest.jpgAllTheResthttps://thecavepearlproject.org/wp-content/uploads/2014/01/flooded-board.jpgFlooded board2015-02-20T19:15:10+00:00monthlyhttps://thecavepearlproject.org/2014/07/31/drip-sensor-update-the-gamma-build/https://thecavepearlproject.org/wp-content/uploads/2014/07/gamabuildinside.jpgDrip Sensor Gamma Buildhttps://thecavepearlproject.org/wp-content/uploads/2014/07/sensortocap.jpgsensortocapJB Plasicweld bonds the accelerometer to the caphttps://thecavepearlproject.org/wp-content/uploads/2014/07/wirefold.jpgWirefoldhttps://thecavepearlproject.org/wp-content/uploads/2014/07/newsdholder.jpgNewSDHolderThese guys are only $1.5 each, and are much easier to work with than the plastic micro SD adaptershttps://thecavepearlproject.org/wp-content/uploads/2014/07/alphabetagamma1.jpgDripSensorIterationsAlpha, Beta & Gamma builds2015-02-13T04:53:22+00:00monthlyhttps://thecavepearlproject.org/2014/09/19/field-report-2014-08-26-the-first-drip-sensor-deployments/https://thecavepearlproject.org/wp-content/uploads/2014/09/comparisontest.jpgComparisonTesthttps://thecavepearlproject.org/wp-content/uploads/2014/09/tetheredinstall.jpgTetheredinstallUnits are tethered so flood conditions don't wash them away.https://thecavepearlproject.org/wp-content/uploads/2014/09/maw_6602.jpgMAW_6602Selecting test locations. (Photo courtesy of Monica Wnuk)2015-01-06T16:50:31+00:00monthlyhttps://thecavepearlproject.org/2014/06/09/bench-top-power-test-results-june-9-2014/https://thecavepearlproject.org/wp-content/uploads/2014/06/20140609_drypowerconsumptiontest_graph.jpg20140609_DryPowerConsumptionTest_graph2014-12-05T15:11:22+00:00monthlyhttps://thecavepearlproject.org/2014/02/22/leaner-meaner-code-for-the-pearl/https://thecavepearlproject.org/wp-content/uploads/2014/02/first-trials-with-cheap-rtc_20140220.jpgFirst trials with cheap RTC_20140220The new terminal block protoshield makes the RTC hookup easy!2016-03-01T20:10:07+00:00monthlyhttps://thecavepearlproject.org/2014/02/04/the-alpha-build/https://thecavepearlproject.org/wp-content/uploads/2014/02/smooth.jpgsmoothGetting down to 600 grit takes allot of hand sanding.https://thecavepearlproject.org/wp-content/uploads/2014/02/alpha-unit-with-anchor.jpgAlpha unit with anchorOne of the alpha housings, with anchorhttps://thecavepearlproject.org/wp-content/uploads/2014/02/boyancy-test.jpgBoyancy testBoyancy testinghttps://thecavepearlproject.org/wp-content/uploads/2014/02/flexijoint.jpgFlexijointPivot joint with no rotationhttps://thecavepearlproject.org/wp-content/uploads/2014/02/corosionontippingbucket.jpgCorosiononTippingBucketCorrosion had locked up some of our drip sensor tipping buckets a few years before.https://thecavepearlproject.org/wp-content/uploads/2014/02/endcaps-with-rings.jpgEndcaps with rings4" rings over 3" end capshttps://thecavepearlproject.org/wp-content/uploads/2014/02/oringsetup.jpgOringSetup2014-12-05T14:52:11+00:00monthlyhttps://thecavepearlproject.org/2014/02/07/project-update-dec-2-2013-2/https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0293.jpgIMGP0293https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0273.jpgIMGP02732014-11-20T00:00:25+00:00monthlyhttps://thecavepearlproject.org/2014/02/06/walking-the-walk/https://thecavepearlproject.org/wp-content/uploads/2014/02/igp9128.jpg_IGP91282014-11-07T17:21:39+00:00monthlyhttps://thecavepearlproject.org/2014/02/09/code-tweaking-dec-11-15-2013/https://thecavepearlproject.org/wp-content/uploads/2014/02/drivinghome.jpgDrivingHomeReturning home after a day of fieldwork in a bug infested swamp.https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0554.jpgIMGP05542014-09-08T19:46:51+00:00monthlyhttps://thecavepearlproject.org/2014/08/14/project-update-power-tests-battery-issues/https://thecavepearlproject.org/wp-content/uploads/2014/08/3lpowerdraingraph.jpg3LPowerDrainGraphhttps://thecavepearlproject.org/wp-content/uploads/2014/08/3lpowertestends.jpg3LPowerTestEndshttps://thecavepearlproject.org/wp-content/uploads/2014/08/duracellbatteryfailure2.jpgDuracellBatteryFailure2testhttps://thecavepearlproject.org/wp-content/uploads/2014/08/duracellbatteryfailure1.jpgDuracellBatteryFailure1At least we know the solvent weld is water tight!2014-08-19T15:36:06+00:00monthlyhttps://thecavepearlproject.org/2014/06/19/project-update-june-19-2014/https://thecavepearlproject.org/wp-content/uploads/2014/06/powersuppliesjun2014.jpgCave Pearl Power Suppliy units 20140601The 171 holders have so much tension, it usually scratches the battery just putting them in!https://thecavepearlproject.org/wp-content/uploads/2014/06/newcropofdataloggers.jpgNewCropofDataLoggers2014-07-21T21:20:35+00:00monthlyhttps://thecavepearlproject.org/2014/06/30/project-update-substantial-overhaul-of-the-cave-pearl-codebase/2014-07-15T00:16:53+00:00monthlyhttps://thecavepearlproject.org/2014/02/05/underwater-housing-mark-ii/https://thecavepearlproject.org/wp-content/uploads/2014/02/balast.jpgBalasthttps://thecavepearlproject.org/wp-content/uploads/2014/02/finalunit-edmallon-the-inventor.jpgFlow Sensor Housing by Edward Mallonhttps://thecavepearlproject.org/wp-content/uploads/2014/02/3accross-2.jpg3accross-2https://thecavepearlproject.org/wp-content/uploads/2014/02/solventweld.jpgsolventweldhttps://thecavepearlproject.org/wp-content/uploads/2014/02/origami.jpgOrigamihttps://thecavepearlproject.org/wp-content/uploads/2014/02/3accross.jpg3accrosshttps://thecavepearlproject.org/wp-content/uploads/2014/02/leak.jpgLeak2014-06-27T15:50:14+00:00monthlyhttps://thecavepearlproject.org/2014/03/03/updated-sram-buffering/https://thecavepearlproject.org/wp-content/uploads/2014/03/desoldered-the-powerled-on-rtc.jpgDesoldered the powerled on rtcI de-soldered the power led, and removed the Bat charging circuit from the RTC board2014-06-17T19:10:26+00:00monthlyhttps://thecavepearlproject.org/2014/02/03/the-original-floatpendulum-idea/https://thecavepearlproject.org/wp-content/uploads/2014/02/original-idea_simple-bobber_small1.jpgOriginal idea_simple bobber_smallOriginal concept sketch from 2011https://thecavepearlproject.org/wp-content/uploads/2014/02/2011_mmaprototype.jpg2011_MMAprototypeOne of the prototypes from 2011. (held together with hot glue.)2014-06-09T23:32:05+00:00monthlyhttps://thecavepearlproject.org/2014/02/05/a-simpler-design-emerges/https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0046.jpgFlow Sensor Housing by Edward Mallonhttps://thecavepearlproject.org/wp-content/uploads/2014/02/innards-for-rubber-encap.jpgDataloggers by Edward Mallonhttps://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0033.jpgIMGP0033https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0038.jpgIMGP0038https://thecavepearlproject.org/wp-content/uploads/2014/02/imgp0029.jpgIMGP00292014-05-07T19:18:27+00:00monthlyhttps://thecavepearlproject.org/2014/02/06/and-talking-the-talk/2014-03-29T00:02:42+00:00monthlyhttps://thecavepearlproject.org/2014/02/14/the-next-steps-2/2014-03-28T23:41:16+00:00monthlyhttps://thecavepearlproject.org/2014/02/07/status-update-nov-26-2013/https://thecavepearlproject.org/wp-content/uploads/2014/02/igp9138.jpg_IGP91382014-02-07T06:19:52+00:00monthlyhttps://thecavepearlproject.orgdaily1.02026-03-09T17:12:42+00:00