This article describes a Hall-effect based magnetometer that uses an inexpensive analog Hall-effect sensor, an Arduino, and LCD. The linearity of the magnetometer is surprisingly good when compared against a commercial magnetometer. This unit can be operated manually or make measurements under computer control, so we’ll use our magnetometer in a computer-controlled setup to measure the BH-curve of small sample of magnetic material.
Could I get by with fewer amenities and shrink the size, weight, and power requirements of my keyer to make it more portable when going on a mini-DXpedition? It was worth an investigation.
In the 1950s and ‘60s, Popular Electronics and other magazines carried ads for strange looking machines called Geniacs and Brainiacs. The ads claimed they were “electric brains” that could play Tic-Tac-Toe and NIM. A while ago, I bought several sets on eBay and I would like to share my experiences of learning about them and my sometimes frustrating — but successful — efforts to get them to work.
This project started out as a challenge to myself: Could I cram a full-featured Z80 microcomputer using DIP packages onto an ExpressPCB MiniBoard (3.8” by 2.5”)? Here’s what happened.
I certainly didn’t need another desk mic, but the prospect of building one from a $1 LED lamp and a spare mic cartridge was a project I could not pass up.
In about 10 minutes and for about $6, you can display the blood flow through your finger. From this measurement, you can extract your heart rate, check for arrhythmia, and even modulate a red light to pulsate with your heart rate. Here’s how.
The Lunch Box Jukebox is a compilation of various projects to make a compact portable music, video, and game entertainment device with the Raspberry Pi Zero at the heart of the Jukebox Internet radio.