Keyboard Hack, No Encoder Chip

[SteveJ34]

With my full size upright cab I used an encoder from Hagstrom. With several single player joy boxes I have made for family and friends, I hacked PS2 pads.

While thinking through couple of bartop projects I'd like to get done before Christmas which will just be single player joy and a few buttons, I thought about doing a keyboard hack seeing as I have a box of old keyboards lying around.

I've cracked the casing on about 4 already and none of them have an actual encoder chip. They are just a simple PCB which mates up to a keyboard grid with a few resistors probably to pair down the voltage for the numlock etc LEDs.

I assume these would work just the same just curious why the design does not include an IC chip that I have seen on all other keyboard hack howto's.

Any words of advice?

Steve

[Bgnome]

I've cracked the casing on about 4 already and none of them have an actual encoder chip. They are just a simple PCB which mates up to a keyboard grid with a few resistors probably to pair down the voltage for the numlock etc LEDs.

I assume these would work just the same just curious why the design does not include an IC chip that I have seen on all other keyboard hack howto's.

Any words of advice?

Steve

i dont see how a keyboard wouldnt have some sort of control chip.  you may be overlooking something, (maybe a small chip covered by a black circle of hard stuff).  could you show us pics of the pcbs?  anyhow, there should be some sort of arrangement of contacts that correspond to the rows and columns of the scan matrix.  the only other way i can think of a keyboard working is if it had direct inputs for all 109 or whatever keys which is something i have yet to see.

[SirPeale]

The chip is usually very small, encased in a black epoxy.  If you look on the PCB you'll likely note this.

[missioncontrol]

I've cracked the casing on about 4 already and none of them have an actual encoder chip. They are just a simple PCB which mates up to a keyboard grid with a few resistors probably to pair down the voltage for the numlock etc LEDs.

if it's what I'm thinking....older keyboards have a pcb right under the keyboard about the size of the keyboard itself. Someone once said you could hack those, but can't remember who or what thread. Check in your box of keyboards for a newer looking one. It should have an encoder close to what you've seen in the how to's

[SteveJ34]

The chip is usually very small, encased in a black epoxy.  If you look on the PCB you'll likely note this.

Upon closer examination, you are correct.

There's a "black blob" covering something.....guess I was expecting a larger chip. Obviously time and technology has enabled the reduction in size of this IC.

Thanks for helping me to "see the light".

Steve