Underwater Arduino Data Loggers

In this post we will describe a process of adjusting raw data from multiple temperature sensors to remove offsets for accurate comparison when they are deployed as a set.

Here the UNO supplies 5v to the (regulated 50mA) NEO6M and 3v to the RTC.

A 3d printed stack of radiation shields goes around the 30mL centrifuge tube housing our 2-module logger.

Once your project starts to grow it’s common to have multiple different sensors, from different vendors, measuring the same environmental parameter.

This post describes a thermistor calibration achievable by people who don’t have access to lab equipment with an accuracy better than ±0.15°C.

2023 is the ten-year anniversary of the Cave Pearl Project, with hundreds of loggers built from various parts in the Arduino ecosystem and deployed for Dr.

Cr2032 Internal Resistance vs mAh [Fig6 from SWRA349] Our peak load of ~8 mA while writing data to the EEprom creates a voltage drop across the battery IR.

Pressure testing has been on the to-do list for ages, but the rating on the PVC parts in our older housings meant we weren’t likely to have any issues.

A typical climate station from our project with other sensors protected from the direct sun under the bricks.

We’ve been deploying our loggers under water since 2013 and although we’ve posted many detailed build tutorials along the way, it’s time to gather some of that distributed material into a summary of the techniques we use.