Capatouch

     

Capatouch Release status: stable [box doku]
Description	With Capatouch you can operate things without touching something.
Author(s)	Bilex
Platform	AVR-GCC

The Idea

The idea of the Capatouch-Boxes is that you can operate things without touching something. Just place your hand or something else above the device and see how the illumination of the box will change their color. If connected to a control unit you can see, feel or hear how things in your environment will change or even disappear at the moment of operation.

Outward appearance

The typical style of a Capatouch-Box is very easy to describe: A small, black painted box made of wood with a translucent plexiglass top. At one side of the box you will find a male XLR connector for power-supply purpose. If connected, it will shine green or red.

Interior design

One box consists of a PCB, an ATMEGA8 microcontroller, a tiny capacitor and a handful green and red LEDs. For proper operation a piece of copper is glued under the top.

PCBs in progress

Technical description

The inner working of Capatouch is very similar to the Labor Klingel, at least the C-Code was just a bit modified. In order to detect your hand or any other device that approaches a box, the capacitance between the copper plate at the top of the box and the world arround is measured. If it changes, the uC switches the the color of the LEDs inside. The third wire inside the XLR connection is used to send the state of each box (red/green - on/off) to the control unit. This is made by using sophisticated Hi/Lo technology.

Functional Test

Control Unit

To establish a connection between one or more boxes and the environment a control unit was built. You can connect up to 12 boxes to the unit by using XLR cables. These are robust and available in large quantity. The connection between the unit and a computer does not use a serial connection or any special protocol, but a modified USB keypad. Inside the unit is a big (lot I/Os) uC to read out the state of any box. If it changes, the uC simulate a keypress by using reed relays. Connected to the computer you can use the system like a USB keypad and trigger what ever you want by using a software like Puredata,MAX/MSP,Processing or even Ableton.

Control Unit

Toilet application

On a toilet we mounted six boxes above the bowls. The whole toilet