my recent reads..

LEAP#456 Pease-out Audio Voltage Probe

The Boldport Pease-out is another tribute to Bob Pease and the classic LM331. As the last of the “classic series” monthly projects, it fittingly takes us full circle to compare and contrast with first project - “Pease”.

the Boldport Club continues - just not at the harrowing pace of 1 a month for the past few years (I seriously don’t know how Saar does it!).

The standard circuit in this kit demonstrates a stable frequency circuit and is adjustable with a variable resistor. I decided to hack it around a bit and convert it into an audio voltage probe:

  • cut the voltage lock and add a voltage probe
  • replace the LED visual indicator with a piezoelectric audio output
  • switch some capacitors to tune the frequencies for an audio range

The probe runs on 5V USB and does a decent little job of providing an audible indication of voltage - with frquency corresponding to voltage level.

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

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Here’s a quick demo..


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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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