Hey, I was actually about to post my setup and some questions as well, but I have my pad working very reliably finally after similarly fixing it repeatedly for years (and the things that can potentially break are easy to replace now). I'll make a separate post later with full details but maybe a summary can help you in the mean time.
I started years ago with a "metal" (inside is entirely wood altho that part is fine) pad from here:
https://www.ddrgame.com/ddrmetalpad.html
After many failures (tiles cracking, buttons stopped working, solder joints lifting, PC driver freezing, connection adapter itself breaking...twice, etc..) I rewired the pad, made my own tiles, wrote my own arduino code to detect presses, wrote my own PC driver to read the keypresses from the arduino and send them to stepmania. Everything has been working now for about a year using it about 4 times a week and I'm a pretty heavy guy.
Tiles
My tiles are made of 1/8" lexan tiles with copper tape on them (https://www.amazon.com/gp/product/B004U7B9HM/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 and https://www.amazon.com/gp/product/B01I1XNY1E/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)
Picture: https://i.imgur.com/fRbFGAO.jpg
Switches
The switches are formed via the copper tape hitting whatever these things are called (interleaved metal contact board?), which came with the pad:
https://i.imgur.com/pcZrUHo.jpg
These are glued to the bottom. The one in that picture actually broke when I was drilling into it (more on that in a sec) and i had to replace it. My only issue is I don't know where to buy those or if there's an easy way to make them so I replaced one of them with this:
https://ddrpad.com/products/force-sensitive-resistor-fsr-sensor-square-interlink
which isn't as big. This is fine although you have to push a little bit more in the center of the pad than the other switches so I'd love to replace it with a bigger one. One of the failures I had with switches being intermittent or not working was the solder joints on these interleaved metal contact boards were letting go. To fix that I attached the wires by drilling in a flat screw to hold the wires in place instead of just the solder. Incidentally, this is also how I broke one of them so be careful lol. The nice thing I like about this design is it's very easy to replace the tiles if they crack, just cut it to the right size with a circular saw and put copper tape on it. I haven't had to replace one yet though and it's been over a year of heavy use. The other nice thing is I don't have a wire coming off of them for the lights although you could put LED strips on the lexan if you want them to light up when you press them. I don't really care about that.
Pad Wiring
Each switch just has 2 wires coming off of it. 1 is the ground wire (these are all tied together), the other is the signal wire for that switch. The signal wires and the ground wire all go to the connector at the front:
https://i.imgur.com/5DJRIWW.jpg
Purchased from:
https://www.amazon.com/gp/product/B07F9S61QT/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
The connector connects to one of these:
https://www.amazon.com/gp/product/B00HKIBV8K/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
which has the corresponding pins connected to arduino pins just via some wires. I was going to make a box for this but it has been reliable for years so I didn't bother.
Picture: https://i.imgur.com/xvSaxyU.jpg
The Arduino connects to the PC running StepMania with the USB cable it comes with and communicates with a custom serial driver I wrote in C#. The code for both the Arduino and the C# program are on my github with instructions for how to build them and what the wiring should be:
https://github.com/kirby561/DDR-USB-Dance-Pad-Driver
Hopefully that helps. Maybe you can adapt part of that for your situation if you don't want to rewire everything again. Also note that I don't use the diagonal arrows but they can be wired up the same way and use the same arduino program/C# software if you do want to use them.
I would love any suggestions to make it better if anyone has them. My only question is what the "interleaved metal contact boards" are actually called and where I can buy more or how to make them if anyone knows!
