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Hardware > 4 face-button GBA

#117995 - mog123 - Fri Feb 09, 2007 12:45 am

Hi, i was just thinking about doing a 4-face button gameboy advance.

The next two buttons would be X and Y respectively (duuh)
This is my main idea: View image

what i want to do, is solder 4 wires (2 for each button) from select, 2 to A and 2 to B, my question is, will the voltage go crazy?

#118488 - 3yE - Tue Feb 13, 2007 11:03 pm

You should disassemble the GBA, turn it on, and probe whether the buttons actually have a common voltage source. Probe against the ground. You will find ground areas where screws and all sorts of metallic shields connect to the board.

Then you make your own switches, and wire this source through the switch to the input wires - ones where there is no voltage upon.

#130204 - mog123 - Thu May 31, 2007 9:09 pm

I forgot about my GBA for a while, now I want to do this project. Really.

All the info I need is:

Do all the buttons connect from Testpoints to ground? Or maybe some go to +V?

#130227 - phonymike - Fri Jun 01, 2007 4:01 am

I would love to help, but don't see how this works. would the third and fourth buttons be read as select+A = 3, select+B = 4? you're gonna need some diodes to prevent the buttons from tying together. if you solder a wire from select, to A, to your switch, it's gonna trigger select and A if you press any of the buttons by themselves.

A = select + A
select = select + A
button 3 = select + A

unless there's a known way to wire this up that I don't know about, you're gonna need more than just wire.

you mine as well just wire up switches to the i/o port, and use general purpose mode to read extra keys, that way you get 4 extra buttons. you're gonna need custom software either way.

#130246 - mog123 - Fri Jun 01, 2007 1:52 pm

I thought about another way.
I'm just gonna make a pcb. The pcb will be just a miniaturized button (combining two buttons L and A), mainly it will be named the X button. And it will all be pressed by a rubber "button"(Don't know how to say it) just like the other buttons work.

Something like this:

http://img516.imageshack.us/img516/5968/buttonmi1.png

I know where the testpoints are.
The same thing will be done with Y ( It'll be L+B)
The only thing i need to know now is:
Do all testpoints connect with GND?