MIDI to anything

[Eric Barbour]

>Eric, this is a really cool idea and a great looking product.  One could
>use relays to control just about anything.  How about setting keys outside
>the normal playing range to control that Leslie speed?  Oh the ideas are
>endless.  Your idea for note on and off using relays and CV trim pots is
>outstanding.  Dual pole relays and trim pots could be used to to create a
>volt and hertz scale that could be tuned together so one set of relays
>could operate both scales in unison I guess.
>
>Thanks for passing along this info.  My electronic design skills are weak
>as I am a high voltage electrician.  But if I understand the interfacing
>correctly, the parallel output latches an external device as long as the
>voltage is between 7 and 35 volts.

???? huh? The 7-35v spec is for the POWER SUPPLY
of the MTP-1. It HAS to be in that range.
The parallel outputs are RELAY DRIVERS. Open collector.
That means that a key-down causes the corresponding 
relay output to be connected to ground.

>> So does the parallel output of the
>device act more like a switch in this process than a supply voltage?  Do
>you think each of the 32 outputs could operate with varied voltages?
>Thanks again,
>Larry Hendry

YOU DO NOT NEED RELAYS TO MAKE A VOLTAGE DIVIDER.
for this thing.
Just string an array of resistors or pots in series. Then connect
+v to one end, ground to the other. Then connect the MTP-1s
first relay output to the junction of the SECOND and THIRD
resistors. Connect your CV output to the junction of the FIRST
and SECOND resistors. 

When the first relay output goes to ground, the voltage divider formed
will give the MINIMUM voltage of the divider. The second relay
output will divide to the SECOND LOWEST CV. And so on.
The resistor values can be adjusted to give the CV scaling desired.

This will work even with two or more dividers. The only connection
of the MTP-1 to the dividers is a ground and a relay output that
grounds. So multiple dividers can be connected to the relay outputs
at once, they will work INDEPENDENTLY of each other (so long as only
one relay output is grounded).

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA