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Topic: Monitor changing polarity cable with the Arduino (Read 77 times) previous topic - next topic

nixo

Hi,

To set the context and what I wanna do, I got a wire that gradually produce anything from 0 to either +7volts or -7 volts.

I need to constantly monitor this voltage with the Arduino.
Any idea someone ?

Thx a lot

P.S. I'm already capable of measuring a straight positive voltage and use it in programmation with the Arduino. It's changing polarity of the source wire that puzzle me here.

Wawa

The Arduino can measure positive-negative voltages with a 3-resistor voltage divider.

Use a 10k resistor between voltage source and analogue pin, a 22k resistor from pin to ground, and a 6k8 resistor between pin and 5volt.
See what values you get with that setup.

Code can subtract the analogue value you get with 0volt input,
and a multiplication factor can turn that result into a voltage.
Let me know if you want help with that.
Leo..

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