A motley collection of ideas
Homemade circuits, experiments, tinker-friendly electronic ideas, and and things related to amateur radio.
It’s well known that bats use their sonar to navigate their surroundings with remarkable precision. As part of this ability, they emit powerful ultrasonic sounds that are characteristic of each species. These sounds are inaudible to the human ear, but with a simple device, we can detect them — which can be great fun and … Read more
This stairwell lighting timer switch was rescued for me from a building by a friendly electrician acquaintance of mine, Sándor Auffenberg. It had been removed because it was “misbehaving,” but it later turned out to be perfectly fine. According to its label, it was manufactured in 1991—so it’s 30 years old… I’ve written before about … Read more
In 2014, the Csepel spark telegraph station turned one hundred years old. The equipment transmitted messages from both Béla Kun and Lenin. I decided that for the 105th anniversary, I would build a spark transmitter myself. Csepel spark telegraph radio station The construction of the Csepel spark telegraph radio station, which marked the beginning of … Read more
Crickets are part of the pleasant atmosphere of summer evenings. And if there are no crickets, the engineer makes… I found this switch in an old electronics magazine, originally powered by a 9 V battery. Thought I’d try a solar version.
Cutting foam or polystyrene sheets with scissors or a saw is an unpleasant task, but with a hot wire, these materials are easy to slice through. You can buy hot wire cutters for just a few thousand forints, but it’s also easy to build one yourself using the transformer from an old reading lamp, a … Read more
Anyone working with electronics will eventually hold a component that you need to identify—what it is, how its legs connect, if it’s the right value, or whether it works at all. Testing with a multimeter A knowledgeable person can learn a lot even with a basic ohm-meter. Some multimeters include diode-test or transistor current gain … Read more
The JYE Tech DSO 068 is a do-it-yourself oscilloscope kit that’s easy to assemble. Anyone who can solder well, has some basic electronics knowledge, understands a little English, and owns a digital multimeter can confidently take on the task of building it. The kit’s list price is $79 (around 23,000 HUF at the time of … Read more
This gadget is actually a continuation of the glimm lamp project. No, I don’t keep horses or deer cattle, so I don’t have a light bulb. However, I do run into electric shepherds while walking through the woods, and it makes me wonder whether or not there is a jelly in it. This thing, which is barely bigger than a pocket knife, is designed to find out.
I’ve always been fascinated by gas-discharge lamps. I don’t know why—perhaps simply because they glow in the dark. Or perhaps because they don’t always shine with a steady light, but sometimes flicker a little, as if they were alive, or burning like a flame. Or maybe because it seems as though the light is created … Read more
Nowadays, in the age of semiconductor diodes, many people don’t even know what this thing is. Yet, they were used in radio and television receivers up until around 1975. Recently, at a ham radio flea market, I picked up an AEG selenium rectifier for a few forints. I started searching online for its datasheet, but … Read more