circuit bent by fastmatt – blog

Random thoughts on circuit bent/bending, schematics, diagrams, techniques, speak & spell, speak & read, speak & math, ebay selling

Tuesday, December 5, 2006

A removable, reusable, user-facing keypad for Circuit Bent experimentation with Speak & Read

Here’s my first gee-whiz post. Last week I decided to hunt around for some new modifications I might be able to incorporate into my circuit bent modifications. Finding it cumbersome and difficult to keep triggering the device by reaching under to press the keys, I had that a-ha moment. Funny, everytime I have a moment like this, the cats hide under the bed and the dogs pace nervously. Maybe it’s the smell of burnt plastic, idunno.

Anyway – I decided that it would be great to have a stand-alone keypad that FACES UP so that I can leave the original device mostly intact on its original faceplate, but trigger the circuitry using the new, temporary keypad. I grabbed one of my spare shells (where I’d already scavenged the guts), and proceeded to dremel out the keypad. There’s no harm in doing this, as long as you follow the natural outline of the keypad. As you can see, I was going for speed and not for pretty. I think a scroll saw might be under the christmas tree for me this year.

With the keypad disembodied, it was now a simple matter of hogging out some notches in the plastic structure underneath, so that the keypad could rest comfortably on the handle of the target device (see pics). Then I simply pull the ribbon cable off the board which will be tested, leaving its speaker and battery connections in place. Finally, I gently connect the ribbon cable of my new keypad into the board and have at it.

With the keypad conveniently facing upwards and up close, I can trigger the sounds with one finger, while testing new circuits with my screwdrivers and test lead clips.

The keypads are pretty much device-specific, so I will probably end up making one for Speak & Math and also for Speak & Spell as well.

Using my new tool, I was finally able to find the body contact ‘pitch up’ circuit (which will work its way into my design within the next few weeks) and also a few cool new glitches I’d never heard before.

posted by fastmatt at 6:30 pm  


  1. test comment.

    Comment by fastmatt — December 5, 2006 @ 8:19 pm

  2. Real nice! Keep up the great work. Good work. Enjoyed the visit!

    Comment by dsdkmkv — December 28, 2006 @ 11:45 pm

  3. Could you say a bit more about removing the ribbons? I wanted to switch a functioning board onto a functioning keypad and put a seemingly self-aware board with the broken keypad (since “On” is the only command it knows anyway…) I am nervous about destroying the proper keypad ribbon. It looked like the whole interface would need to be installed, but your project seems to imply otherwise. Please advise.

    Comment by grayson — January 14, 2009 @ 1:43 am

  4. Never mind, wow that was easy!

    Comment by grayson — January 14, 2009 @ 1:47 am

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