AW: AW: Ribbon controllers

[Haible Juergen]

	>The sensor outputs two voltages, one for pressure and one for
	>position.  The voltage range is roughly 0 to 5 volts.  The
Position voltage
	>gets slightly filtered (just a couple of .01uf caps to ground
to kill big
	>spikes) and then goes directly into one of the analog mux
inputs.  The
	>Pressure voltage goes into the base of a small-signal NPN
transistor,
	>configured as a basic transistor switch.  This transistor's
output switches
	>between 0 and 5 volts, and is also read by the same mux.  

This is good news. So if you once have this component, you're done.
Would be very interesting to know what it costs. And: Maybe there are
other synths that have longer ribbons, which would work in the same way?

	>I don't have a JP8000, but as far as I remember, its ribbon is
not actually
	>"pressure sensitive", per se.  The ribbon's "Pressure" sensor
is probably
	>there so the CPU can detect when you have placed your finger on
it, and when
	>you have released it. 

Sounds reasonable.

>  It can then start reading the Position voltage, using
> the voltage of your first Position as the "zero" point.  (It does work
> this
> way, doesn't it?)
> 
And the good news is that we can use this old Yamaha circuit (from the
CS-80) to do this completely analogue. Great !!

> I don't know how much the ribbon sensor would cost from Roland, but if
> there's any interest, I could find out (I do Roland authorized
> service).
> 
Please find it out !

JH.

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