RPi theremin

[gasmask]

Maybe it's wrong place for this kind of topic.
Does anybody know how to make a theremin
with Raspberry Pi?
I don't want to buy original (the price is the problem) and
I also hate this types of analog schematics.
Is there a chance to make theremin?

Gas

[greaser_au]

This looks like a good place to start.

Now you just need to figure out how to make midi come out of a  the pitch antenna & volume plate...  There was a silicon chip project nearly 10 years ago that did this, however it uses analogue techniques (a complete analogue theremin) to generate the pitch and volume, which is then converted to MIDI...  the Jaycar kit (now all but unobtanium)  and the self-help group at thereminworld for it.

Most of the 'real' digital things like this I have seen are optical rather than capacitive - there are plenty of examples of this for entry-level tools like the Pi & Arduino platforms.

david

[gasmask]

Thanks for reply. I only found a 'touchable' solution of changing the capacity.
It would be very difficult to make it with antenna....
Gas

[potul]

You can try this:

-Use the "Invisible touch" circuit to sense the antenna and provide a CV signal.
-Feed this into an ADC, and send it to Rpi, read value and send appropriate midi signal. You might need an external ADC or some tricky method, as Rpi doesn't have ADC. (maybe arduino is a better option?)
-Be sure you check the voltage levels are ok, you might need to reduce the CV voltage in order not to damage the RPi
http://topopiccione.atspace.com/PJ16TPCInvisibleTouch.html

[potul]

Or try to reuse the work of this guy, and use it to create a CV signal.

http://www.guitarrista.com/phpbbforum/viewtopic.php?f=29&t=31481&start=120

[WhiskeyMadeMeDoIt]

You can try this:

-Use the "Invisible touch" circuit to sense the antenna and provide a CV signal.
-Feed this into an ADC, and send it to Rpi, read value and send appropriate midi signal. You might need an external ADC or some tricky method, as Rpi doesn't have ADC. (maybe arduino is a better option?)
-Be sure you check the voltage levels are ok, you might need to reduce the CV voltage in order not to damage the RPi
http://topopiccione.atspace.com/PJ16TPCInvisibleTouch.html

You can use the MCP3008 for 8 channel 10 bit ADC. It works  with RPi .
Here is the chip and a tutorial : http://www.adafruit.com/products/856