Paraplegic pedal update

[Bill Spurlock, RPT]

Recently I posted inquiries about designing a head-operated pedal system for a
paraplegic client. In the meantime, I've been in touch with the engineers at
PianoDisc. They realized the need and potential market for such a system, and
are in the process of building a prototype power supply and soleniod system. My
client will beta test this and it could eventually be on the market. I'll post
results when we're done.

The project is a little bit complicated because the large pedal solenoids
require a high initial power to lift the dampers, but then the power must step
down for the duration of the sustain to prevent overheating the power supply and
solenoid. The power must also be DC, to avoid a 60 cycle hum from the solenoid.
The PianoDisc system modulates the power in this way when playing back from a
disc, but in this case we will be using a head band-mounted mercury switch to
turn pedaling on and off. So, the engineers are adapting the electronics to the
work with the signal from the mercury switch. They also have to build in a
safety control so the solenoid will automatically turn off after 15 seconds or
so; this will prevent the solenoid from being accidently left on if the head
band is removed and left unattended in the "on" position.

Bill Spurlock