Everything for Electronics
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The Electric Brains of Yesteryear

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.

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Build an Instant Heart Pulse Sensor

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.

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Build a Freezer Alarm Circuit

I’m not sure if it’s absent mindedness or just old age, but sometimes I’ll forget to close the food freezer lid after shopping for groceries. With food prices seemingly going up every three days, there’s really no good time to lose a pile of food because of a simple mistake. This article describes my solution to the freezer problem.

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Build the FLiPVox Laser Theremin

In my previous Theremin article, I described the first of my laser Theremin projects: the LASERVox. This is a simple-to-construct Theremin-like device that acts as a MIDI controller for a synthesizer. In that article, I discussed the possibility of a more analog style laser Theremin that has its own built-in synthesizer or pitch generator. That’s the topic of this article! We’ll build the FLiPVox: a continuous pitch laser Theremin with its own mini synthesizer.

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How You Can Intercept Secret Messages Being Sent to Spies

Believe it or not, there are powerful radio stations all over the world sending out messages to spies every day, and you can hear them with an inexpensive shortwave radio and a simple antenna. You probably won’t be able to decode them, but it’s a real kick to tune in these clandestine signals.

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Build the LASERVox MIDI Laser Theremin

The Theremin, invented by Leon Theremin (Lev Termen) in Russia in October 1920, was one of the first electronic musical instruments. It’s also the very first instrument of any type that you play without touching it in any way. An expert Thereminist can play as expressively as a violinist or cellist. If you want an instrument with violin levels of sensitivity, then a regular Theremin is for you. If you want an instrument that’s easier to play and that can control your MIDI synthesizer, then that is precisely what the LASERVox offers. The LASERVox is a perfect project for the novice because it’s a real instrument that can be built very easily with just a handful of components.

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Build a Wireless Doorbell Pager for the Deaf

This is a great device for those who need to know when an Amazon package or a friend/relative has arrived at the front door.

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