Antenna to control LED/LDR setup?

[C Bradley]

Where can I find information on circuits for theremin type controls; i.e., move your hand or foot and control a function on a stomp box?

I work in a shop that makes electrical connectors and there's brass strip 2" wide laying around, so I figured that I can make something similar to Mr. Z Vex's wah-probe pedal.

I'm assuming that it requires a very high gain driver stage to light an LED.

[ninoman123]

Well...many people have asked for this, but nobody is gonna say because Mr.Vex has asked us not to do so, so we respect that.

[C Bradley]

Well, I guess I'll just have to break out the textbooks and dig.  

[Peter Snowberg]

For Theremin info.... the best place is probably http://www.thereminworld.com

Once you have the control voltage, the next trick is controlling the circuit. The easiest interface is to use an LED/LDR cell to modify a resistor value, but your options depend on the specific control you're working with. You may also be able to mix control voltages with the existing circuit and then there are OTAs to attenuate signals too.

[Paul Perry (Frostwave)]

If you search (that is, the search function above, on this list) for 'proximity', you will get 120 or so hits, a couple of which are useful.
Personally, I find theremin & RF controls a bit difficult, so I use a reflected light technique (an infra red diode, modulated at 50KHz or so, reflects off your foot or hand or whatever ( :!: ) and is picked up by a phototdiode & demodulated for the control voltage. At least, that is what i do in my commercial Frostwave SpaceBeam theremin.

[C Bradley]

If you search (that is, the search function above, on this list) for 'proximity', you will get 120 or so hits, a couple of which are useful.
Personally, I find theremin & RF controls a bit difficult, so I use a reflected light technique (an infra red diode, modulated at 50KHz or so, reflects off your foot or hand or whatever ( :!: ) and is picked up by a phototdiode & demodulated for the control voltage. At least, that is what i do in my commercial Frostwave SpaceBeam theremin.

Thanks for the hint! I came across some good info, but it appears that it's still a bit complex for now. I'm putting this thing in a 4" diameter box, so there's not a lot of room. Your IR LED idea sounds cool, and I'm betting that it doesn't take many parts to accomplish. Can the photo diode be used like an LDR?  :?  I've got a photo transistor, but can't figure out how to use it. I no longer have the packaging so I have no data.

[puretube]

http://diystompboxes.com/sboxforum/viewtopic.php?t=35647

[Paul Perry (Frostwave)]

Can the photo diode be used like an LDR?  :?  I've got a photo transistor, but can't figure out how to use it.(

A photodiode behaves nothing like a LDR. (but, speaking of LDRs, you will probably find it much easier to make a beam of light, say from a car headlight bulb, focus it on a LDR, and waggle your gfoot in the beam).

To use a phototransistor, just wire it as a normal one stage transistor amplifier. The varying light on the phototransistor creates a base current, whihc the transistor amplifies.