If you are thinking that old style switch matrix is not cool enough for your project, then you must take a look at this. This projects takes you to a "Touch generation" ride demonstrating a practical implementation of QMatrix technology used today for making capacitive touch sensor interface.

The basic idea behind this technology is to transfer the charge through the sensor capacitance to a tank capacitor gradually, until a charge sufficiently large to be measured builds up. After that, a current is applied to the tank capacitor and the time that it takes to reach zero crossing is measured. When sensor surface is being touched, the fingers steal part of the charge to be dissipated by the body and less of it gets transferred to the tank capacitor. This difference can be measured and tried to tell if a button is being touched or not.



As you can see keyboard runs so smooth and looks pretty cool Project is made on an ATMega8 running at 16Mhz. The firmware is completely open source along with schematics and PCB designs. Click here for more information on this project.