Tachometer Uses Light, Arduinos

To measure how fast something spins, most of us will reach for a tachometer without thinking much about how it works. Tachometers are often found in cars to measure engine RPM, but handheld units can be used for measuring the speed of rotation for other things as well. While some have mechanical shafts that must make physical contact with whatever you’re trying to measure, [electronoobs] has created a contactless tachometer that uses infrared light to take RPM measurements instead.

The tool uses an infrared emitter/detector pair along with an op amp to sense revolution speed. The signal from the IR …read more http://pje.fyi/QHgVw3

Paul Jacob Evans


Stretched PC Case Turned GPU Cryptominer

We don’t do financial planning here at Hackaday, so we won’t weigh in on the viability of making money mining cryptocurrency in such a volatile market. But we will say that if you’re going to build a machine to hammer away at generating Magical Internet Monies, you might as well make it cool. Even if you don’t turn a profit, at least you’ll have something interesting to look at while you weep over your electricity bill.

Sick of seeing the desktop machine he built a decade ago gathering dust, [plaggle24w5] decided to use it as the base for a cryptocurrency …read more http://pje.fyi/QHcyTT

Paul Jacob Evans

3D Printing Brings a Child’s Imagination to Life

Telling somebody that you’re going to make their dreams come true is a bold, and potentially kind of creepy, claim. But it’s one of those things that isn’t supposed to be taken literally; it don’t mean that you’re actually going to peer into their memories, extract an idea, and then manifest it into reality. That’s just crazy talk, it’s a figure of speech.

As it turns out, there’s at least one person out there who didn’t get the memo. Remembering how his father always told him about the elaborate drawings of submarines and rockets he did as a young boy, …read more http://pje.fyi/QHcZ14

Paul Jacob Evans