my recent reads..

LEAP#451 Arc Lighter

A “High Voltage Arc Kit” perhaps attracts the kind of person liable to make it go up in smoke, which is probably why this kit ships with redundant parts.

The circuit is an interesting demonstration of a step-up transformer using a feedback winding to control the main power circuit. It is the same circuit used in commercial “plasma lighters”, confirmed by another great teardown by bigclivedotcom.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

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A quick demo.. aside from learning more about the circuit, I’ve yet to come up with a practical use for this;-)


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LEAP#449 Parrot Sound Effects

The Parrot is a reproduction of a “bird chirp” circuit I found referenced in background research materials for Kelly Heaton’s amazing bird that was one of the Hackaday Circuit Sculpture contest winners.

This circuit is an interesting combination of two LC elements - one modulating the other - around a single transistor.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

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Here’s a clip from the workbench, demonstrating some of the sounds that can be produced:


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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 on GitHub

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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 not suitable for the flashing LED as it is liable to get stuck on a single colour, so I’ve added a diode/capacitor charge pump to provide a more stable power source for the LED.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

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