Introduction

I discovered Dance Dance Revolution by accident, with this article about losing weight (not that I’d need it) on slashdot. I found the game Stepmania and wanted to try it at no expense.

So I decided to build my own dance pad. I first built a ridiculous cardboard-made prototype, just to be sure that I enjoyed this game. Cheap, but absolutely unreliable. Then I decided to build something robust, and made one out of wood. Very robust, very reliable, very uncomfortable, VERY noisy.

I wanted to keep the reliability, but gain comfort, and remove the noise. I thought it might be possible to build something that would work just like touchpads, or touchscreens. After a bit of research I found about capacitive switches, and a great circuit schematic by John Simonton gave me the basic idea of how to do the detection. Coming up with something that works well cost me a great deal of time and headaches, but I’m fully satisifed with the result and I think I have reached most of my goals.

Here’s what my dance pad looks like:

Yeah, sure. It’s ugly. I know. No fancy graphics (though I could easily add them), no blinking lights, nothing. ’good-looking’ has never been a goal, remember ?

But it is comfortable, has a great feeling, won’t fold itself under your feet when you’re playing, and is really silent. No complaints from my neighbours so far ;-)

The pad consists in two separate parts: the pad itself of course, the thing you dance on, you know, and an electronic circuit that you plug between the pad and your computer. That circuit works by looking for changes in the capacity formed by an electrode located on the pad, and the earth. When someone presses his foot against the pad, this capacity becomes higher and this can be detected. That means that this pad can’t be used with shoes; however the player does not need to be bare-foot, socks are OK.

Building the pad itself is really easy and should not take more than one hour or so. It’s just a matter of cutting the foam, putting it together with adhesive tape, and then adding the pads, which are not much more than a sheet of aluminium paper covered by a sheet of transparent plastic.

I have designed two versions of the electronic circuit:

• v1: The analog circuit, probably the one that I have used the most, because it was the first. It uses standard 74LSxx and CMOS4001 chips, and is to be plugged into the joystick port, or into the parallel port.
• v2: The digital circuit. This is the one that I use now. It uses a PIC18F2455 microcontroller and is connected to the PC via USB. Much easier to build (NOT to design...) as there are much less components to solder. Plus the settings can be done with a program that I wrote, instead of potentiometers. Much more practical. And you can plug two dance pads !

And it works !

Questions ? ddrsimon@gmail.com