LEAP#447 Measuring Capacitance with Digital Logic

Capaci-meter is a Boldport remix of a classic capacitance measurement circuit designed in high school by Jez Siddons of Peak Electronic Design.

The device takes a very interesting approach - rather than trying to measure the actual capacitance or charge time, it uses a derivitive function (the capacitor’s effect on the frequency of a 555 timer) to infer capacitance.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo (more...)

LEAP#446 RGB Joule Thief Night Light

I recently got hold of some 5mm RGB Flashing LEDs from a seller on aliexpress - some slow and fast flashing varieties just out of curiosity. Here I’ve put one the slow-flash kind in a “night light” circuit.

I decided to power from a little 1.5V CR1216 coin cell. To boost the voltage sufficient to power the LED, I’ve attached a toroidal joule thief circuit. The oscillating voltage produced by the joule thief is (more...)