How can detect a very low voltage (0.2 V) with the Raspberry Pi? [closed]

Question

I'm a beginner in electronic and I want to use a GPIO input to detect 200 mV.
Is that possible ?
I think that we can increase the voltage, decreasing the amperage.
But I don't found a way to do it.
Any help is useful !
Thanks !

Answer 1

You will need to use additional analog circuitry.

A current is generally measured by running it through a shunt - a (low resistance) resistor of known value and applying Ohm's law to the detected voltage. Since you already say 0.2V, rather than some Amperage, I believe you have that part covered.

The next part is to convert it to a digital value. This can be done with an Op amp in a Comparator configuration.

Answer 2

All the Pi's GPIO are digital, i.e. on or off.

For the Pi to detect a voltage like 0.2 V the simplest solution would probably be to add an ADC (Analogue to Digital Converter).

Search for a popular ADC such as the MCP3008 for examples.