Yet Another Hardware Mod


Dzz

stmia r0!, {r2-r9}
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Hi all!

Shamelessly stealing ideas that others have put forward on this forum, I decided to mod my spare gp2x. The goal is to replace the joystick with a D-pad and repaint the case. I'm in no particular hurry but the project is underway and I thought it might be useful or entertaining to document the process.

Note: I'm not going to make kits or sell anything, this is just for my own amusement and if somebody else can learn something from my eventual success or failure, that's cool.

http://gp2xgamer.com/mod.html
 
xinfernoofdantex posted on Jul 27 2006 at 07:01 PM said:
isn't the other mod using the same QD pad...
Yup, it sure is! You got a problem with that? :)
 
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xinfernoofdantex posted on Jul 27 2006 at 07:07 PM said:
No, only that it would make your mod and his mod extremely similar
It's not an originality contest. I just want a D-pad so why not use the part that looks the best?
 
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Dzz posted on Jul 28 2006 at 12:57 AM said:
Hi all!

Shamelessly stealing ideas that others have put forward on this forum, I decided to mod my spare gp2x. The goal is to replace the joystick with a D-pad and repaint the case. I'm in no particular hurry but the project is underway and I thought it might be useful or entertaining to document the process.

Note: I'm not going to make kits or sell anything, this is just for my own amusement and if somebody else can learn something from my eventual success or failure, that's cool.

http://gp2xgamer.com/mod.html


How do you connect that atmel chip? That looks nice because of size. I would like to use that but I don't know how to program it. Could you sell programmed chips?
 
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DaveC posted on Jul 27 2006 at 08:00 PM said:
Dzz posted on Jul 28 2006 at 12:57 AM said:
Hi all!

Shamelessly stealing ideas that others have put forward on this forum, I decided to mod my spare gp2x. The goal is to replace the joystick with a D-pad and repaint the case. I'm in no particular hurry but the project is underway and I thought it might be useful or entertaining to document the process.

Note: I'm not going to make kits or sell anything, this is just for my own amusement and if somebody else can learn something from my eventual success or failure, that's cool.

http://gp2xgamer.com/mod.html


How do you connect that atmel chip? That looks nice because of size. I would like to use that but I don't know how to program it. Could you sell programmed chips?
I will make a circuit board for the atmel chip, just like Radek did for his.

Note that I haven't even started making a circuit; I'm not 100% sure how to hook it up to the gp2x even yet, and I certainly haven't written any code for the chip yet. It'll be quite a while before this is done, if it ever even ends up working.

I think Radek's design is a lot better for making kits. The pins on this atmel chip are 0.8mm apart, and soldering them is a nontrivial task.

Having said all that, all of what I do will be public, you can build a programmer that attaches to a computer parallel port for a couple bucks or buy one for less than 20.
 
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Dzz posted on Jul 28 2006 at 12:57 AM said:
Hi all!

Shamelessly stealing ideas that others have put forward on this forum, I decided to mod my spare gp2x. The goal is to replace the joystick with a D-pad and repaint the case. I'm in no particular hurry but the project is underway and I thought it might be useful or entertaining to document the process.

Note: I'm not going to make kits or sell anything, this is just for my own amusement and if somebody else can learn something from my eventual success or failure, that's cool.

http://gp2xgamer.com/mod.html


Some other hints.

It is useful to leave the QD pad as is and use the carbon pads to press the switches.

The thickness of the QD pad is too thin to fit through the case and have the flange behind the case. You will need to trim off the ridge on the qd pad and use the rubber to hold it.

leave the center "tit" intact, the pad should rock a bit and not press left/fight simultaneously very easily.

Use switches that are 50-60 gforce, if they are too stiff control will suffer.

Those are my findings as I am working on the same project as you in parallel. My solution will be more tailored to a kit though.

If you need anymore info let me know. I have been working on this it just takes time.
 
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DaveC posted on Jul 29 2006 at 01:00 AM said:
Some other hints.

It is useful to leave the QD pad as is and use the carbon pads to press the switches.

The thickness of the QD pad is too thin to fit through the case and have the flange behind the case. You will need to trim off the ridge on the qd pad and use the rubber to hold it.

leave the center "tit" intact, the pad should rock a bit and not press left/fight simultaneously very easily.

Use switches that are 50-60 gforce, if they are too stiff control will suffer.

Those are my findings as I am working on the same project as you in parallel. My solution will be more tailored to a kit though.

If you need anymore info let me know. I have been working on this it just takes time.
Thanks for the hints!

My current plan is to reduce the thickness of the case in a small area around the flange so it can still be behind the case. That may be okay for me to do assuming I can pull it off, but it's not what you'd want in a kit as the chances for failure are very high. Are you planning to glue the rubber skirt to something to keep the pad in place?

Yes, i am planning to have the little nubs push the buttons, same as you.

The switches I have are 100-150ish gf, it doesn't seem too stiff but I guess we'll see.
 
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Dzz posted on Jul 29 2006 at 01:43 PM said:
DaveC posted on Jul 29 2006 at 01:00 AM said:
Some other hints.

It is useful to leave the QD pad as is and use the carbon pads to press the switches.

The thickness of the QD pad is too thin to fit through the case and have the flange behind the case. You will need to trim off the ridge on the qd pad and use the rubber to hold it.

leave the center "tit" intact, the pad should rock a bit and not press left/fight simultaneously very easily.

Use switches that are 50-60 gforce, if they are too stiff control will suffer.

Those are my findings as I am working on the same project as you in parallel. My solution will be more tailored to a kit though.

If you need anymore info let me know. I have been working on this it just takes time.
Thanks for the hints!

My current plan is to reduce the thickness of the case in a small area around the flange so it can still be behind the case. That may be okay for me to do assuming I can pull it off, but it's not what you'd want in a kit as the chances for failure are very high. Are you planning to glue the rubber skirt to something to keep the pad in place?

Yes, i am planning to have the little nubs push the buttons, same as you.

The switches I have are 100-150ish gf, it doesn't seem too stiff but I guess we'll see.


You may want to look into these:

http://dkc3.digikey.com/PDF/T062/1437.pdf

It is the P/n P12930SCT-ND. only 50 gf .

Since you will have the resistance of the rubber plus the switch these would be good. You also may want to make the throw not too much but also not too little or you will get erroneous activations. I don't have the rubber skirt resting on the switches themselves I have them resting on a PCB with holes drilled for the 4 nubs. When the pad is pressed the nub(s) will poke through the holes on the PCB and activate the switch. That seems to give it the right throw distance.

I will just capture the rubber with the PCB that it rests on. It will be a bit loose to allow for it to be pressed easy.
 
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