Using an (apple) keyboard as a button controller?

[kriista]

So I'm building something that requires lots of buttons. I'm wondering if I can get a broken apple keyboard, cut an appropriately sized section out of the aluminum cover and access the tactile switches + keys.

I want to be able to use the keys as individual buttons, so wiring up directly to the pads underneath.

I would imagine that keyboards are matrixed or something non-linear for switch communication, but is it possible to cut traces and run wire to points of contact under each key?

Maybe even adding LEDs underneath each (if it's backlit style keyboard).

Has anyone done something like this and/or is it possible?

[cr0sh]

In theory - yes it is possible, but practically - I wouldn't attempt it. Even if you were able to cut the alluminum away (not sure why you would take this route - surely the keyboard can be taken apart in some manner), you might find that the "keyswitches" aren't making contact with any actual PCB traces or such, but rather are some kind of flexible polyester plastic membrane of sorts, with the traces on this membrane (impossible to solder to, but you could use conductive glue, possibly).

Also - if you are planning on a lot of buttons - you wouldn't want to wire them up individually. Instead, you would want to hook them up in a row/column matrix - which is likely how they are hooked up to the microcontroller in the keyboard itself. Your best bet, then, would be to take the keyboard apart (this might be difficult depending on the keyboard), locate the controller, then locate the lines coming from the keyboard. There will be noticeably fewer lines than there are keyswitches, of course. From there, you would need to decode the matrix (no small feat in itself depending on how it is set up). Once you know this, then you can hook those lines into your Arduino, and be able to read them just like the original controller did.

Finally - if you need something with a lot of buttons - look into building and part for a Monome controller - plenty of projects and examples out there...

[kriista]

The specific project I'm using it for is an existing circuit that has 8 momentary switches in it already, so this would be replacing those with something more ergonomic.

Hmm, it would suck if it's a polyester thing that can't be soldered to. I did buy some conductive glue recently but I don't know how much I would trust it (not used it yet).

I'm basically building an updated/upgraded version of this:


http://rodrigoconstanzo.com/The_Party_Bus.html

So the apple keyboard would be those buttons along the front of it (though 8 now instead of 6), so something compact and "fast" feeling would be ideal.

The ones I used before (in that picture/build) are nice since they are illuminated but they aren't terribly sensitive. I don't press the button down all the way, sometimes it wouldn't register.

[David Pankhurst]

You can hack a keyboard, as long as you use a ps2 (or usb with ps2 adapter)

I first heard of this in the book "Practical Arduino" (which is a must read) and he has the pin layout to connect to the Arduino on his site:

http://www.practicalarduino.com/projects/ps2-keyboard-or-mouse

As well, here's an 'Instructable' where someone hooks up the keyboard:

http://www.instructables.com/id/Extra-inputs-for-Arduino-with-a-keyboard/

As to whether the internals of your keyboard are hackable, just pry up a key and take a look...

[kriista]

I'd want to gut the thing down to 8 keys/buttons worth so doing it like that would probably be harder to do (keeping all the connections/wiring/traces intact).

I did finally buy a broken apple keyboard and tried to take it apart. It was horrible to do so. It's held together by some crazy strong glue (and I don't have a heat gun).

It got all bent while I was taking it apart and the button spring bits are super delicate and all broke too etc...

To top it off the traces are all on this super thin plastic which I'm sure would melt at the first touch from a soldering iron.