Hi,
I am working on a project that will have both positive and negative voltages as outputs to a Pro Mini. One of my colleagues suggested that the ATMega328 cannot read negative voltages into the ADC. I have been poking around and cannot find an answer.
Can the Pro Mini read positive and negative voltages into the ADC?
Richard
Hi Richard.
Unfortunately the ATmega328 can not measure a voltage below ground and it would likely damage the chip if you tried.
A work around would be to use a op-amp setup to output 2.5 volts with a zero volt input. When the input goes below ground the output will fall below 2.5 volts and when the output goes above ground, the output will be above 2.5 volts.
An Arduino would be able to measure something like that but you’d need to write your code to figure out if the voltage is negative or positive.
Thanks. I was trying to avoid using an inverting op amp because I am tight on space and power.