Calibration done !

Here is the law between the actual battery voltage and the decimal value sent by the ADC0831 :

Ubatt (volts) = 0.04 * adcbits (one byte variable) + 0.6163

Monitoring methods :

Since the BS2 is not very convenient with fractional calculus, the decimal value sent by the ADC will probably be processed by the PC104. I will still use the BS2 as an interface allowing "on demand voltage monitoring", or when it's useful to know / show the actual voltage value.

I may just test the [adcbits] variable with a simple IF...THEN loop. If it's below a threshold, then it's time to charge the robot. Easy programming, but the voltage will remain unknown from the user. Hey wait ! It's supposed to be an autonomous robot... I guess this method will be my favorite !

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Edit (March, 1st) : I corrected a little mistake in the chart and in the linear interpolation equation...