Monkey Couch Guardian


My cats like to jump on furniture and shed their fur, which ends up on my clothes. To stop them, I’m using a Monkey Couch Guardian. I made it from one of those old-fashioned cymbal-banging toy monkeys, modified with an inexpensive Arduino microcontroller and a proximity sensor. Now when a... Read more »

The Fire Piston


Carl von Linde was dead tired. The eminent engineer, considered the father of the modern refrigerator, had just returned to his home in Germany from a lecture tour that took him to, among other places, Malaysia. This being the late 19th century, the voyage had taken months. Von Linde had... Read more »

Dodecahedron Lamp


People appear symmetrical, but even the most perfect human face shows irregularities if we compare the left side with the right. Perhaps this is why the absolute, rigid symmetry of crystals seems beautiful yet alien to us. Unlike DNA’s soft spiral, a crystal’s molecular bonds align themselves to form regular... Read more »

The Autophenakistoscope


Motorize a phenakistoscope, a 19th-century parlor novelty that preceded motion pictures, and keep its frames synched to an LED strobe by using a sensor and an Arduino microcontroller. Invented in 1832 by Joseph Plateau, this device creates a moving picture from a sequence of stills arranged on a spinning disk... Read more »