Have you ever found the need to measure the capacitance of a capacitor? No multimeter handy (for shame)? Well, as it turns out you can actually measure capacitance using your Arduino Uno, with no external components, and only ~20 lines of code.
[Jonathan Nethercott] does an excellent job explaining a capacitance test circuit which uses a reference capacitor to calculate the unknown capacitance. He further explains that, with the Arduino Uno, you can remove the reference capacitor from the circuit, and simply use the stray capacitance present in the board and microcontroller, which can be calculated. This results in the test circuit being as simple as plugging in your capacitor to pins A0 and A2. [Read more...]