Small Geiger-Müller (G-M) tubes make ideal sensors for pocket-sized devices to detect radioactivity. However, even a small G-M tube needs an anode voltage in the 400 to 600 volt region. Here's how to generate that voltage from a 9 V battery.
For most of us, measuring DC current means putting an ammeter or low resistance current shunt in the line. But now, you can build an adapter that can be used with your voltmeter and will measure 100 amps DC.
I can hardly imagine an electronics enthusiast without some sort of test bench. This can be as simple as a folding table and a couple of hand tools, along with a cheap DMM (Digital MultiMeter). Or, it can be as elaborate as a spare room just loaded with TE and a full complement of tools and accessories to go with it.
The most powerful computer in the universe is actually the simplest. Explore the concept of Turing Machines and experiment with a simple Turing Machine simulator.
Browsing in a craft store, I happened on a box that looked like a small book. I thought it would be cool to see if I could put enough electronics in it to make the cover pop up as a Halloween prop. As with most of my projects, that concept was just the beginning of a small project that became a larger project due to scope creep. I would always think — wouldn't it be even cooler if I did this ... and then that!
A tennis ball suspended from the ceiling at just the right spot is the classic solution, but with more than one person using the garage — possibly driving different cars or just backing in — that just wouldn’t cut it. Here's a high tech solution for the high tech hobbyist.
Listening to shortwave radio is very interesting, and filled with the voices and music of far-off lands. Digging a bit deeper, there is another world of shortwave radio that does not use conventional sounds. It is the realm of data transmissions.
In the fast moving world of digital electronics, I find it incredible that the vacuum tube — a piece of early 20th century analog technology — has managed to survive. It should have bitten the dust long ago but that just did not happen. This back-to-the-future one-tube radio is made with readily available parts, operates on 12 volts, and offers amazing performance.
Frequency counters have been around for years as a standard piece of test equipment in both commercial and hobby labs. If you need one for your workshop, take a gander at the one discussed here.
Sure, launching model rockets is cool and all, but what if you could incorporate some science and learning into the fun, too. How high did it go, exactly, and what did it do along the way? What happens when the rocked drifts to Earth out of sight? The flight computers described here have the ability to collect data; control other payload instruments (cameras, sensors, radios, etc.); trigger activities in flight, such as igniting a second-stage motor or deploying parachutes or glider wings; send simple telemetry data via a built-in transmitter; and act as a radio beacon to find the rocket once it's landed.
