The folks over at Adafruit have been busy designing an LED matrix wristwatch for a while now. The circuit works great, but since this watch is powered by a coin cell battery, they’d really like to get the power consumption as low as possible. This means they needed a test rig to measure the consumption of each firmware revision, but how exactly do you build a voltage logger that works with voltages and currents this small? It turned out to be a very interesting project, with plenty of info on how to build an accurate voltage logger for really small projects.
