Fully Regulated ATX Power Supply

Now, let me begin this article by stating that this *is not* a so-called “conversion” with an LM317 (or any other linear regulator in general) like you might have seen on thousands of other web pages, nor a so-called “lab” supply that was made just by shorting the PS-ON pin. This is a real ATX to regulated supply conversion, which might come in handy for you.… [more]

Semiconductor free Geiger Counter

Tried searching the keyword “geiger counter” on Google, or even better, on YouTube? Now, how many of them contained a multitude of transistors, analog microchips or even digital microprocessors, and no shielding at all? Well, whatever the count is, a majority of them – if not all – are going to fail miserably, due to a huge electromagnetic pulse, when the… [more]

Nixie tube tester

This very simple circuit can be used to verify the proper functionality of each cathodes in a Nixie tube, which was the predecessor of the solid-state LED 7-segment display, back in the 1960s and early 70s. The main anode voltage is obtained from a simple, battery-powered flyback inverter with just enough voltage to strike the glow discharge, and an adjustable resistor current limiter… [more]

Arduino Mega2560 nixie clock

Some five years ago, I had a RepRap 3D printer setup running the Marlin firmware on an Arduino Mega 2560 board. With that long gone, I was thinking about some other projects I could try on it: a floppy drive controller, and perhaps a clock, with some neon indicators I have managed to salvage from a 1970s benchtop multimeter of Czechoslovak provenience. Even though I have to admit that it… [more]