Category Archives: phototransistor

Homebrew Oscillator Is In a Glass By Itself

Great things happen when we challenge ourselves. But when someone else says ‘I bet you can’t’ and you manage to pull it off, the reward is even greater. After [WilkoL] successfully made a tuning fork oscillator, his brother challenged him to make one out of a wine glass. We’ll drink …read more

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Posted in laser hacks, misc hacks, oscillator, phototransistor, wine glass, wine glass oscillator | Leave a comment

LED Matrix And A Phototransistor Make A Reverse Camera

A digital camera has an array of sensors that captures light reflected or transmitted onto it. This build is something closer to a reverse camera – a single sensor that makes images on a matrix of LEDs. And we think it’s pretty neat.

We have to admit to being a …read more

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Posted in Arduino Uno, led hacks, matrix, phototransistor, raster, scanning, sensor, shift register, TIL78 | Leave a comment

Laser Harp Sounds Real Thanks to Karplus-Strong Wave Equation

The harp is an ancient instrument, but in its current form, it seems so unwieldy that it’s a wonder that anyone ever learns to play it. It’s one thing to tote a rented trumpet or clarinet home from school to practice, but a concert harp is a real pain to transport safely. The image below is unrelated to the laser harp project, but proves that portable harping is begging for some good hacks.

Enter this laser harp, another semester project from [Bruce Land]’s microcontroller course at Cornell. By replacing strings with lasers aimed at phototransistors, [Glenna] and [Alex] were able …read more

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Posted in harp, Karplus-Strong, laser, Microcontrollers, music, musical hacks, phototransistor, pic32, plucking, vibration, wave equation | Leave a comment

Awesome Illuminated Arcade Spinner

[Tinker_on_Steroids] made some awesome looking spinners that not only light up when spun but are a really professional looking build on their own. Before we’d watched his assembly video we were sure he’d just added on to something he’d bought, but it turned out it’s all custom designed and made.

In case you’ve never played the old arcade games, a spinner is an input device for games such as Tempest or Breakout where you rotate a knob in either direction to tell the game which way and how fast to move something. In Tempest you rotate something around the middle …read more

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Posted in misc hacks, neopixel, optical switch, optointerrupter, phototransistor, spinner | Leave a comment