Analog input buffer

Hi!

I'd like to use any pot value between 10k to 500k into an analog input. My goal is to output midi cc using any guitar volume or expression pedal. I guess I need an op-amp buffer to get correct analog input impedance. What kind of circuit do I need? I have no exprience on op-amps.

Thanks!

To use an op-amp as a buffer you want to wire it as a "voltage follower" by connecting the output to the - input. Connect the + input to the wiper of the pot. Connect the ends of the pot to Arduino +5 and Ground. Connect the power pins of the op-amp to Arduino +5 and Ground. Connect the output of the op-amp to an Arduino input pin.

Looks like the Microchip MCP6231 would be a good choice.

Note: If the pot is under 100K you don't need a buffer. Just connect it across +5 and Ground and connect the wiper to an input pin. If it is over 100K you can either use a buffer or call analogInput() twice to give the sample capacitor more time to charge.

Thank you!

I will try a MCP6231.