I have been trying various methods for the D-pad, and have come to the following conclusions:
1) Rubber pads
Taking away the D-pad rubber pads, building a unit to the top of the GP2x to hold it and adding a flat circle for the button pressing (as I thought of earlier). In principle, this seemed a good idea, in practice, it failed. It is nearly impossible to adhere these rubber pads to anything, there is no grip. The pads make contact in an ununiform manner, and don't pivot, so the top comes off. Unsuccessful. I spent all yesterday making and playing with this concept, to end up unsoldering the wires and removing the unit, and going back to my original idea! I believe the idea of using tack switches would not gain any more success as although they can be mounted securely and easily, and would be better, they would share the problems between 1) and 2) - great for 4 way, cumbersome for 8 way.
2) Commercial D-pads
(eg like Grahf is working on): these are of course excellent as 4 way pads, and will do diagonals (of course), but it is "less natural" and harder to use them for diagonals too as you need to press harder and more precisely to get a diagonal. Sure, this works, but games like Vektar for example, I don't believe would be quite as seemless to play. A D-pad after all only has 4 precise buttons in specific places. There might be a way around this, I am sure Grahf will keep us all posted on developments. The other issue is the mounting of a commercial D-pad. Not only will you need to use a small one, like from a GameBoy for example, because as Grahf states, the GC's D-pad is too big as it stands, but it causes mounting problems in the GP2x case. It will be interesting to see the final solution to this one.
3) My original method
I have come to the conclusion (after trying other ways, and various "improvements"), that my first attempt (originally posted a picture of it) worked great, and the controls were great, but could slip on the joystick hole and work free, and it was hard to get the integrated Push button to be reliable. My next major version is the one I am going back to - yes FluffyPanda, sticky floor tiles (2 layers - one to stick to the GP2x and have a hole extracted to mould around the GP2x joystick hole, the other to sit on top, small hole through for wires, rest of it used for the circuit of the D-pad and centre push. This stops the final assembly from moving during use, but can be removed if required (non permanent). My original method with tinfoil is, I believe, the only viable way forward. making the contacts (and centre push button) on this top piece of floortile and a circle for the D-pad (contacts sandwiched between both) works great. Tinfoil is flat, mallable and a good conductor or electricity for low voltage. This has the advantage of seemless movement for all 8 directions - press the top circle piece in any direction and it works easily. The only issue is the material separating these two sets of contacts - it has to act as a pivit yet be in continual contact between both surfaces, it has to compress in any direction, and return 100% back to its original state. A sticky foam pad conforms to this, apart from the very last bit - after a few hundred uses, a foam pad looses some of its ability to rebound fully. I believe I have the "final solution", but have to make yet another prototype. The upside of this method is that it works beautifully, and is updatable; the downside is that it looks "less pretty" as the mounting base needs to be on the GP2x itself. You can cover the components in a variety of ways, the result looks perfectly fine, but not "wow" factor on looks necessarily.
DaveC - sure, why not? Have a go. I can only use houseware items, so my result will work great but not look "moulded". If someone can take my working idea (in 3 above) and incorporate this into a moulded commercial quality unit, at a good price, great. If you can do this, experiment away! One thing for sure, there is quite a lot of work and time required to make each unit, unless you can acquire pre-moulded bases and tops. Keep us posted on your developments, good or bad.
