Hi all !
Sorry if this is such a basic question (and maybe it’s been answered too many times already). I want to measure a resistance with on my arduino board.
From the different message I’ve read : it has to be done with a voltage divider. One should do this schematic:
Analog input pin unknown R1 | XX Ohm R2 +5 ----^^^^^^^-----+----^^^^^^^^^^------
I am guessing that if I want to have as much precision as possible, I should put the smallest resistance on R2. However if I put a very tiny small resistance, the board will try to send as much current as possible, therefore I’m going to burn my board. And guess: I don’t want to burn my board.
So how should I calculate the resistance to put ? I wanted to use the formula u=r*i … u=5Volts (given by the board), r is the smallest resistance I look for, but I don’t know the maximum Intensity I looked at the hardware page and couldn’t find it. They talk abour 3.3V, 5V, pvm ports, etc. they got me lost :(
Thanks if you can help :)