Hey all,
I need some advice on a basic touch-switch.
I'm hoping to make a "Dance mat" for a computer game I play: This is four 20x20cm touch sensitive pads arranged in a cross formation, attached to a flat board or foam mat and laid on the ground. You play the game by putting your feet on the right pads at the right time. I'm disappointed by the life and reliability of commercial soft (fabric-like) pads, and cannot obtain a commercial hard pad, so I want to make my own.
The capacitive touch sensors I've seen on the 'net look unsuitable, as the electronics are too complex (I'm just a beginner! :)), and I'm worried that they may be more like proximity switches than contact switches (In the game, it is just as important to be not standing on a pad at the right time as standing on it, so if it detects a hovering foot, it would be a disaster).
The design at:
is attractive as it is so bloody simple :). However, I have some questions. My pads' sensing areas will be prototyping circuit boards, with every second row forming one contact and every other row forming the other. I want my touch pads to replace the buttons on a butchered USB hand-held joystick - I suppose that the joystick will expect a circuit to be completed between two contacts when the button is depressed, with low (practically no) resistance. So is it reasonable to arrange my circuit like this:
How do I choose my MOSFET? Can I adjust the sensitivity of my touch pad?
Cheers, Nicholas Sherlock