Our inspiration for this project came when we were trying to hook up more then two players for our club Dance Dance Revolution (DDR) setup. The only additional setups we had were flat foam pads, but we discovered that the sensitivity was bad enough to be a detriment to score. Thus, we wanted to build a pad that would have a sensitivity as high as the actual cab, but portable enough that we can bring around and just plug in to a setup.
Our portable DDR pad sends signals from each of the Force Sensitive Resistors (FSRs), which we have a program on the Adafruit Feather continuously running while the game is in play. The program takes care of a couple of things, including mapping the signals to arrow-key outputs (which plays the Stepmania software we have on the computer). We also programmed an auto-calibration feature in the program, so the pad stays at peak sensitivity even if there are external forces like obstructions.
We first created a prototype to test out all of our wiring and as a mild proof-of-concept that this project will be do-able. The prototype is a very small version, which uses physical buttons rather than the acrylic tiles we have on our final portable pad. We then designed a multi-layer tile outline, where we could sandwich all of our electronics in the indents of the middle layer, while keeping them undamaged from all of the force of people playing on the pad. The main structure of the portable pad is done using laser-cut 1/4" plywood, while the panels (arrows and center) were made using laser-cut 1/4" acrylic. On the electronics side, we simply soldered power, FSR, analog port, resistor, ground in series for each of the four FSRs we used.
Our main challenge came from designing the structure of the pad. CADding was difficult, since we wanted the pieces to fit as well as possible together, since excessive sliding affects gameplay. Additionally, we had a lot of trouble getting the laser-cut pieces that we wanted, with a lot of difficulties communicating with the laser-cutting party. This resulted in us having to use the band saw to finish a half-done laser-cutting job for some of the layers.
We are very proud that we managed to make a functioning DDR pad over the past 24 hours! We were very anxious about it working after putting everything together, so testing it for the first time was a relief. Now, since we have some reassurance that we can reliably make this functioning pad, we are both looking for ways to improve it (mostly structural, as well as material), and we can try to produce these pads with people in the club that would like their own.
We learned a lot about CAD, measurement and planning, as well as electronics such as circuitry flow and soldering! MakeMIT has been a great experience for us, and we're glad that we could participate.