Author Archives: edmallon

Measuring Electrical Conductivity with Arduino: An Overview

This post is a summary of my background research into electrical conductivity (EC) to serve as a backdrop for my own humble attempts at this interesting measurement challenge. I’m sure there are many other approaches that I’ve yet to discover, and … Continue reading

Posted in Developing other sensors | 2 Comments

Arduino Data Logger: 2017 Build Update

If you need a logger with a rugged waterproof housing, it’s still hard to beat the crimped-jumpers build released in 2016. However sometimes I just want a quick bare-bones unit for bookshelf test runs while I shake down a new sensor. I can whip up a breadboard combo in about twenty minutes, but they stop working if … Continue reading

Posted in DIY Arduino Datalogger | 2 Comments

Switching off SD cards for Low Power Data Logging

The tweaks I discuss in the  power optimization post bring sleep current on a typical build into the 0.1-0.12mA range; leaving the sleeping μSD cards  as the largest remaining power consumer on the Cave Pearl loggers.   And those cards have been a burr under my saddle for quite some time now, as they … Continue reading

Posted in DIY Arduino Datalogger, The quest for low power | 19 Comments

Calibrating Thermistors on a 3.3v Arduino

Selecting a thermistor (& series resistor) value Most of the material you find on thermistors makes the assumption that you are trying to maximize sensitivity and interchangeability. But oversampling gives you access to enough resolution that sensitivity is less critical, and interchangeability only makes sense … Continue reading

Posted in Developing other sensors | 4 Comments

Improving Arduino ADC resolution with Dithering & Oversampling

While I was figuring out how to read thermistors, I came across claims that you can improve the resolution of any Analog-to-Digital converter with a technique called oversampling & decimation. I had already doubled the number of ADC bits covering my target temperature range by powering a thermistor divider from the rails … Continue reading

Posted in Developing other sensors | 3 Comments

The 2016 Cave Pearl Project ‘Year in Review’

We made great strides in 2016 with development of new calibration procedures and continued refinement of the housings & connectors for multi-sensor builds. At this point I’ve cobbled together more than 130 loggers for the Cave Pearl Project. While I still have a way to go before I reach Gladwell’s … Continue reading

Posted in Expedition Reports & Updates | Leave a comment

DIY Arduino ProMini Data Logger: 2016 Build Update

Its been almost a year since the last stand-alone logger tutorial, and I continue to receive questions from people adopting the platform in education settings.  That feedback makes it pretty clear that soldering is the biggest stumbling block for beginners, so I have reconfigured the build to use pre-made … Continue reading

Posted in DIY Arduino Datalogger | 19 Comments