Voltage monitoring, first steps

Just like your cellphone, my robot needs to monitor the voltage of its battery to avoid overdischarge. This feature is not yet implemented.
It means that I check quite often the battery with my metrix when playing around with the robot.And it means that I've probably overdischarged the Ni-MH a couple of times...
Monitoring the voltage will also allow to use more efficient and lighter batteries like Lipos, that were not affordable when I started this project.

Today, I tried a simple A/D converter, the ADC0831 to monitor the battery using the BS2. Okay, it was the very first test, so it may look a bit messy :

Wires all over, but it worked just fine :

At this time, the output is an 8-bit value, without any reference voltage or calibration. This will need some math and adjustments in the code... This will be done on the future power supply PCB that I am going to make soon.

To be continued !