A simple capacitance meter implemented on ESP32-C3. The only external component required is a 2Mohm resistor. This code will work on any microcontroller with an ADC. From my tests, this meter is accurate down to 10 pF and possibly lower.
I'm working on updating this code, but it currently will not be accurate above 500 pF. The code will also be less accurate on different microcontrollers.