Touch-based Synthesizer Is A Wiring Nightmare

May 11, 2011 by Mike Szczys 10 Comments

[Jane] wrote in to let us know about the touch-based synthesizer she and her classmates just built. They call it the ToneMatrix Touch, as it was inspired by a flash application called ToneMatrix. We’re familiar with that application as it’s been the inspiration for other physical builds as well.

A resistive touch screen in the surface glass of the device provides the ability to interact by tapping the cells you wish to turn on or off. Below the glass is a grid of LEDs which represent sound bits in the looping synthesizer track. Fifteen shift registers drive the LED matrix, with the entire system controlled by an ATmega644 microcontroller. Although the control scheme is very straight forward, the jumper wires used to connect the matrix to the shift registers make for a ratsnest of wireporn that has been hidden away inside the case. Check out the demonstration video after the break to see what this looks like and sounds like when in use.

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Touch Sensors: Overview, Theory, And Construction

February 4, 2011 by Mike Szczys 21 Comments

This collection of touch sensor information should be of interest to anyone who liked the simple touch sensor post from Thursday. That was a resistive touch sensor and is covered in detail along with AC hum sensors that trigger based on induced current from power lines around you, and capacitive touch switches like we’ve seen in past hacks. Each different concept is discussed and clearly illustrated like the slide above. [Giorgos Lazaridis] has also put together individual posts that build and demonstrate the circuits. We’ve embedded his resistive sensor demo video after the break and linked to all three example circuits.

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Making The Bulbdial Clock Touch Sensitive

August 13, 2010 by Mike Szczys 14 Comments

We never thought about it before, but having the controls on the bottom of a clock is a bit of an inconvenience. [Alex Whittemore] mutes the LEDs on his clock each night and after a while, decided he should make the mute button into a touch strip on the case. You’ll remember that the Bulbdial clock uses colored LEDs to create the effect of a sun-dial, casting colored shadows for each hand of the clock. It makes sense that this would put off a pretty good amount of light at night. [Alex’s] original thought was to use a capacitive touch sensor but complexity and cost were in his way. What he ended up with is a resistive touch switch based off of two metal strips. He used metal repair tape but suggests copper foil as he was unable to solder to tape. When your finger touches the two strips it completes the circuit for the base of a transistor, which in turn grounds the mute button on the clock. Cheap, simple, and illustrated in the video after the break.

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