Pages tagged circuit:

Secret Knock Detecting Door Lock - Made by Steve Hoefer

Weil Türen durch geheime Klopfzeichen aufgehen sollten.
While working on another project I ran across the Arduino knock sensor tutorial. Sensing a single knock is a great little project for learning about microcontrollers, but what about sensing specific knocks? Seeeeecret knocks? And if we could detect a secret knock, shouldn't it unlock a door? If you can't tell by looking this was cobbled together from spare stuff around the lab, it's not much more than a piezo speaker, a tiny gear reduction motor, and an Arduino. And PVC pipe.
"Seeeeecret knocks? And if we could detect a secret knock, shouldn't it unlock a door?" (via @yetzt)
Very neat contraption that can unlock your door based on a programmed knock. Not very practical but still pretty awesome.
Categories of electronic circuits
Welcome to our Website! We are here to show You how to make various interesting electronic devices on your own. Some of the devices are: Amplifiers, Power sources, Metal detectors, Alarms, Insect repellant, light, sound or touch sensitive devices, Whistle responder which produces sound when called by a whistle and our visitor's favorite Light and LED devices… We can’t name them all right here, so we suggest You browse through our collection of diagrams on your own
Build over 400 electronic devices by yourself. All circuits are grouped into several categories.
Plans for all manner of electronic devices!