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.

Computer engineer Thiery Guennou based in France has created a new Arduino compatible precision frequency counter 5 or 120 MHz. The inspiration behind the Arduino board was to build an open, very ...

The time was then displayed on an OLED display attached over I2C, while raw pulses from the 555 were counted on a 7-segment display as a useful debugging measure.