Hi, everyone, i’m new user of Raspberry Pi Pico thing and I have a project in which I have to use Pico as a multimeter. I need to read analog voltage from really old device and the input is DC signal (around -1 — 5 V) with small AC component. The signal can also be negative, and it needs to be scaled. So I assembled the sircuit on breadboard - it’s basically a voltage divider connected to ADC
![Image]()
And when I monitor this signal with simple ADC pin reading sketch, it’s readings is kinda varying a lot, whereas it should be nearly constant and change on action. Meanwhile, a simple multimeter is reading correct voltages.
So what could be an issue with this sircuit? Maybe there is better solutions to my problem? Note, that I currently don’t have the opportunity to buy expensive ADC solutions, I want to make it as cheap as possible.
And when I monitor this signal with simple ADC pin reading sketch, it’s readings is kinda varying a lot, whereas it should be nearly constant and change on action. Meanwhile, a simple multimeter is reading correct voltages.
So what could be an issue with this sircuit? Maybe there is better solutions to my problem? Note, that I currently don’t have the opportunity to buy expensive ADC solutions, I want to make it as cheap as possible.
Statistics: Posted by anubis_by_himself — Tue Oct 28, 2025 6:24 pm