Dual Battery Monitor Adapter

This is a design I sketched up tonight for a compact in-line dual battery monitor adapter for Arduino. Those of you who have looked into battery monitoring for Arduino will know that the maximum voltage that the Arduino's ADC pins can handle is 5v.

Here's a simple design (5 solder points) that will take your servo battery (~6v) and your Arduino battery (~9v) and reduce the voltage from them to safely measurable levels. I wouldn't push this design past measuring two 9v sources as it gets a bit close to the maximum.

Assuming you are using the voltages specified, the power usage is 58.5 microWatts. If you use 10M resistors instead, you can reduce that by a factor of 10 (und so weiter...).

I will be making one of these for ABE and a half-one for the WRPC so that they can monitor their own battery levels.