USB Keyboard Hack 4 Foot Pedals

January 24, 2010 | Filed Under Blog 

I’m working out how to trigger things in Isadora for the interactive percussion and video piece I’m writing for Logan Dean.  I want something any computer will recognize without having to install Arduino drivers.  So, I ripped apart a USB keyboard to make foot pedals that will trigger single key commands (there are a number of Instructables on this = this one and this one, for example, online = for that reason, I am not writing good step-by-step instructions – this is more of a documentation for myself).

NOTE: What I just realized was that when you plug the USB into a computer it asks you to press “the key to the left of shift” etc. . . . so I’m working this out now.

So first I ripped apart the keyboard:

Below is the part that we’re after, when two of the contacts are connected, a key command is sent to the computer:

Below is the other side:

I took a picture of the two layers within the keyboard and raised the contrast to very high.  Then I filled in all the circuit wires with colors using the paint bucket tool in Photoshop.  Then, I figured out what combination produced what key commands and entered them on the chart below.

NOTES: Make a switchboard (matrix) like old telephone operators used so key commands can be changed OR use switches to enable changing between a set number of different key commands for different pedals.  How many pedals?  Have a shift pedal so it will double what pedals can do — maybe have this be a toggle pedal with an LED showing that shift is down . . . will this slow down the computer? I’m afraid to use caps lock because of no state indication on the pedal.

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