Theramin style device control LED light intensity ?

[Freddy205]

Is it possible to use a theramin style device to control the light intensity of a LED? Any ideas for a cicuit/schematic?

[guitarhacknoise]

Like a REAL theremin with the two antena?
or the cheater style, one ant. and a volume pedal?
More than likely, optic would be the way to go,  it'd be more of a "magical" visual effect seeing as you could completely hide the device.
(what? magical visual effect?)
Without prying, What exactly are you trying to do?
could it be as simple as a 9v to a limiting resistor to a photo cell to an led to ground?
-matthias

[Freddy205]

A theamin with one antena.
I've built an oscillating fuzz pedal and I want to use the thereamin style thing to control the frequency of oscillations.

[Paul Perry (Frostwave)]

Freddy205, I'm not quite sure exactly what you want, but most simple 'pitch only' single antenna theremins can be easily converted to give a control voltage output, wheich can then be used to control a led, if you want.
If you have a particular theremin circuit in mind, someone can probably make a suggestion.

[zachary vex]

sounds familiar somehow.  8^)

[Freddy205]

I'm not using a fuzz factory Zack, I'm using the Parallel Universe. Any simple theramin circuit that could do the job will be fine!

[sean k]

I'm thinking about this as well to vary resistance on something like Tim Escobedo's T.M.K.
 The idea would be to have the feedback and gain controlled by two plates placed either side of your hips,gosh,I've just thought of hall effects working off magnets.That might be even easier to get together as I have a schematic somewhere for using a hall effect driving an op amp which in turn drives a J-fet as a variable resistor but even that could be simplified to using the hall effect straight to an LED driving an LDR.That way all you'd need is the hall effects on stands and magnets on the sides of your trousers or arms or even on the ends of the guitar.

[zachary vex]

i have a magnetic money-clip that gets me stuck to chain-link fences and cars all the time.  it's no end of trouble.  neodymium magnets may have been a mistake.  8^)

[ryanscissorhands]

I would like to figure out a way to implement ZVEX Probe(TM?)-esque controls into a pedal. Like modding Tim's Uglyface to have the frequency controlled like the ZVEX Probe series.

The other thing I've wanted is a trem pedal which has expression pedal (or "touchless" expression pedal) which controls either depth or speed, the other set by a pot.

Part of the reason is that I'm trying to perfect usage of the Ebow, a most fun invention, although not as practical for live performance. THe effect I want is to have some minor trem available for sustained notes, to simulate the vibrato on, say, a violin. (Hey, maybe a vibrato pedal?). Or to control speed of vibrato, to get that funky sound in the background of Beck's "Cold Brains" off of mutations (anyone know what I'm talking about?).

Yes, expression pedals are key, but if I can figure out a way to run it off of a theremin-like control system, all the better.

I'm sorry, I just tried to hijack this thread. I'm bored at work, and forum trolling.  And I'm getting paid to do it


ryanscissorhands

[william]

I've been wanting to impliment a therimen style control for a wah pedal I wanna make.  It's an opitcal wah that I hope to build using a VTL5C1.  I've been looking at the Paia theremax schematic to see how they arrive at volume control.  The two things that have been stopping me is I'm unsure if zach has a patent on its use in stompboxes, or the look would be similar to him pedals.  Although I wouldn't use plexiglass on the pedal.  Well those and I have to figure out how much of the therimax is actually needed, and find the coils.

[Paul Perry (Frostwave)]

William, I think going RF theremin (like the theremax) is doing it the 'hard way'.
In my commercial SpaceBeam, I just use an infrared diode driven by a 555 oscillator at (IIRC) 200KHz which reflects off a nearby object, and is picked up by a photodiode & amped up & rectified to give a variable voltage that changes with the proximity of the reflecting object (hand, foot, headstock etc).
Roland's lawyers tried to get me for infringing their dumbass D-Beam, but I pointed out that this technology goes back to the 60's.

The diy robot guys have good proximity detectors also. I wondered why one of the standard ones has such a strange response range & then found they were designed to control the flushing of urinals.. they detect when you arrive & more importantly when you leave.

[dave h.]

interesting you should bring that up paul, because as we speak, im working on a theremin that flushes urinals.

[Dji]

interesting you should bring that up paul, because as we speak, im working on a theremin that flushes urinals.

It's comments like this one that make me wish we had a rating system. (I'd give you the highest marks, of course.)

Oooh... I know. I want to make a Urimin(tm): force controls volume, length of stream controls pitch? I could be the Clara Rockmore of the Urimin(tm), amazing the world with my short but poignant compositions. That is, until I died of liver failure from drinking too much beer.

[ryanscissorhands]

Well, if your theremin flushes urinals, you should make it so that, while using the urinal, you can play songs. . .

Nevermind. Bad idea.

Paul, I'd love to get a bit more information on this infrared/detector thing. Except that it's in your commercial pedal, so perhaps it's not "Here, I'll show you!"-type of material.

[Paul Perry (Frostwave)]

http://www.active-robots.com/products/accessories/sensors.shtml shows
the Sharp reflective distance sensor with analog output.

More general background: http://www.ceeo.tufts.edu/al/en10/manual/sensors.html

For the EEs: http://roboflag.carleton.ca/resources/technical/ir_beacon.shtml

Honestly, I don't think the way I did it was the best possible, plus the IR detecting diode that i used is pretty well 'unobtanium' :x
Originally I thought that a 'lock-in' or synchronised detector would be needed for discriminating against ambient light, but not so!!