Here I'm trying to use a touchpad as a switching device with four switching controls.I just started working on touch interfacing so I decided to start with a pretty small and easy project on touch interfacing.
The touch interfacing device that I used here is a simple 4-wire resistive touchpad.The circuitry and the working details of a 4-wire resistive touchpad is discussed below:
That's how a resistive touch device operates by detecting the pressure applied at a point.
<Refer the above shown fig.>..By just applying a potential gradient across the 2 electrodes of the X-plate and Y-plate,we get a varied voltage value for touch at different points of the plate which is converted to digital value through an AD converter.
I divided the screen space into 4 quadrants(1,2,3 and 4) and used it as a switching device with 4 switch control that gives response to my touch which results in glowing of either of the 4 LEDs.
This was a small project on touch interfacing.This project can be of a great use if you want a switching device(let say a keypad).Instead of using a keypad with some fixed number of switches one can just modify the resolution of this touchpad to use it as a M X N keypad(M,N can be set as anything).Its both cheap as well as efficient.I'll try to modify this project to tracing the touch pattern with a touchscreen.
