Bleep Labs Thingamagoop modulated by Arduino with accellerometer

February 5, 2013 · Posted in Uncategorized 

Reactive Music Experiment.
Accelerometer on springy stalk flashing led to modulate sound from Thingamagoop .

The Thingamagoops are really just simple, analog type synthesizers that you control in a different way. The Thingamagoops have oscillators just like any synth. On analog synths the oscillator that creates the actual tone you hear is called a VCO or voltage controlled oscillator. The Bleeps work a little differently so we’ll just call it the main oscillator. Instead of using a keyboard, the main oscillator in the Thingamas is controlled by a photocell. Here’s what the waveform from the main oscillator looks like.

When there is a lot of light hitting it, the resistance across the photocell goes up and the oscillator yields a higher pitch. Less light lowers the resistance and pitch. When the switch on the right is up, the oscillator is in a high range and when it’s down it’s in a lower range. One neat thing about the photocell is that it reacts to different kinds of light. Florescent lamps and TV screens give the Thingamagoops a harsher tone while natural and incandescent light produce a cleaner one. Just like any analog synthesizer, the thing-a-ma-s have another oscillator that effects some variable. This is usually called a modulator or LFO. Here the modulator’s waveform is pretty close to a square wave.

The modulator’s frequency is controlled by the knob and the type of modulation is selected by the switch on the right. When the switch is up the modulator is effectively turning the output of the main oscillator on and off. This yields a simple beep beep beep at lower frequencies but at higher frequencies sidebands are created. Sidebands occur when the modulator is oscillating inside the audible range . This creates new frequencies that are multiples of the oscillator’s frequencies.

When the modulator switch is down, the modulator is changing a variable in the LEDacle’s circuit. Now you have some control over its rate of blinkatude. The LEDacle is a modulator too but instead of adjusting knobs and switches to change how it interacts with the main oscillator, you physically move it around to effect the sound. The light from the LEDacle can be pointed at the photocell to rhythmically change the pitch. Not only can you use the speaker inside the Thingamas to listen to crazy beeping nonsense, you can also use the 1/4inch ouput jack to plug it up to all kinds of things. Plug it into some guitar effects and an amp for some indescribable electronic madness.

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