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Beginner keyboard hack help
Kaeru the Frog:
I've just taken appart a keyboard. The PCB has 27 connectors which only seem to be grouped together based on where screws are needed. How can I figure out which one connect rows in the matrix and which ones connect columns? The first 8 connect to one side of the contact sheet, 18 to the other, and one to nothing. Does 8x18 sound right? Does that mean 8 individual inputs allowed?
tom61:
My best recommendation about keyboard hacking is this: Don't! Hack a gamepad or get a keyboard encoder instead. Much, much easier.
seaner:
Look up the datasheets online for the matrix decoder chip. You can use an ohm-meter to beep out the traces and figure out which pin goes where.
Zeitgeist:
As far as an18x8 matrix does it really matter?
IMHO The best thing to do is download either ghostkey (dos) or virtua keyboard (windoze) & map the inputs.
http://www.arcadecontrols.com/arcade_downloads.shtml#Utilities
You can then solder leads to your pcb & check what inputs cause key blocking & ghosting & what do not.
Doing this, I was able to get one of my projects, using an old gateway keyboard pcb, to be ghost/block free except for fire button #6 on the player 2 side.
I can hit any diagonal with both sticks & press all six buttons on player one side as well as the first five on player 2 without any conflicts whatsoever.
For the price of the keyboard ($0) I can live with this.
It will take quite a while to test this, but if a keyboard hack is your choice, then this is what you must do or else you may have a situation where you can not move up when player 2 presses button one etc...
Of course you will have to remap the default inputs in mame to match your control panel inputs.
I do have to agree with tom61 however, a gamepad hack or an ipac or keywiz is the way to go.
AlanS17:
I don't think a keyboard hack is such a great idea. Even if you can do it, it's probably not worth the effort. There may be places to skimp in your project, but this probably shouldn't be one of them. Shell out the extra $25 and buy a J-Pac or an I-Pac or something. If you have to hack something, hack a game controller. With a project that's going to cost 100's of dollars, anyways, why go cheap on one of the most important parts?