Touch sensors: overview, theory, and construction

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 music with tech stolen from Predator

This is a second generation Manta, a touch-based controller with visual feedback made to use with Max/MSP. The hexagonal size and the patterns seen in the video after the break remind us of the arm-based computers the Predators sport in the movies. Like the previous generation, this controller can tell not only which of the 48 sensor you’re touching, but how much of your finger is touching it. The sky is the limit on extensibility with this type of data, but for now you can just try out the pre-built plugin and see how it goes. New with this rendition of the Manta is the use bi-color LEDs which adds another lay of interaction with the PC to which this is tethered.

If you don’t mind giving up the touch controllers for good old push buttons perhaps this Harmonic Keyboard is right up your alley. Continue reading “Making music with tech stolen from Predator”

Keyless entry using touch sensing

[Alex] sent us this slick little keyless entry system. He wanted a discreet way to trigger the door to unlock. Knocking was too loud, and would give away his secret access code. He decided that touch sensors would be the best. Initially he planned on using the doorknob itself, which would have been awesome, but it was just too much surface area for his touch sensor. Ultimately, he settled for a wire he could touch.  An Arduino detects whether or not the correct code has been put in and initializes a high torque servo which turns the doorknob from the inside.  In the video, after the break, you can see that it works fairly well.

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