Keyboard for GTA04

Al Johnson openmoko at
Thu Mar 15 15:10:20 CET 2012

On Thursday 15 March 2012 12:57:23 Dr. H. Nikolaus Schaller wrote:
> During the "Openmoko Stammtisch Munich" yesterday, we
> have once again discussed options to build a special GTA04 keyboard.
> And now I think we have found a way to really square the
> circle. The square being functionality and the circle being
> cost.
> The idea is to use:
> * off-the shelf pushbutons (Panasonic has some nice and very
>    flat SMD buttons readily available at DigiKey)
> * a Shapeways made custom case
> * a not very sophisticated PCB with the buttons, a Bluetooth
>    HCI module [1], a small LiIon battery and a microcontroller scanning
>    the keyboard and supporting USB charging
> Now comes the key idea: having a shapeways printed case makes
> it possible to think about a keyboard built into a replacement battery
> cover. It makes it a little thicker than normal, but you can detach it
> and use it as a keyboard.

I was with you up to the bluetooth + battery part. Why not use a slide out 
keyboard with a TCA8418 and wired i2c connection to the main board? The board 
should be cheaper and simpler, the plastics little different to a sliding 
bluetooth device, and there'd be no messing about remembering whether you'd 
charged the keyboard.

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