Electromagnetic pedals?

[crazybuilder]

Does anyone know about these pedals that use a "virtual switch" to turn them on and off. My friend uses a wah made like this so all you have to do is pass your foot over it and it wahs. It is soo cool.  I would like to make a DIY version of this, but dont know how to do it. Any ideas?

-J

[crazybuilder]

Ok i did some research and they are called zvex pedals. They are sooooooo cool check out this like! http://www.zvex.com/movies/wahprobe.mov This is the pedal i was talking about.  

It says it works like this: "The probe circuit generates a small (one or two inches high) "bubble" of RF energy at about a million cycles per second above the copper plate. As your foot or hand (or any wet or metallic object, for that matter) approaches the copper plate, the RF field is disturbed and the circuit reacts by increasing the brightness of an LED, which drives a photoresistive cell and controls the Z. Vex wah circuit. The wah circuit is actually the Seek-Wah sound circuit without the sequencer control. It's also the same wah circuit as the one in The Drip guitar that I make. The only difference is the boost circuit in this Wah Probe model."

How can we make this into a DIY project?

-J[/url]

[crazybuilder]

That has to be the coolest thing for guitar I have ever seen!

[YouAre]

its not electromagnetic, its called a theremin.

[crazybuilder]

so how do we go about  making one of these? I am assumming we can use a basic wah circuit (crybaby) but then what?

-J

[crazybuilder]

I just found this this could help with the beginnings of a schemo.

http://www.geocities.com/SunsetStrip/Studio/2987/theremin.html

Is anyone willing to work on this? It is just so cool watch the demo video in the Zvex link.

-J

[Hal]

hahahaha you're so obsessed with this.... :-D

if it works like a theremin does, it changes its capacitance as you move towards and away from the plate.  Read about theremins...

I'm waiting for Z. Vex to post here and tell you :-D

[crazybuilder]

haha well its so cool. Lets figure it out. and build one. Do you have any idea where to start with a schemo?

[Peter Snowberg]

http://www.thereminworld.com/


ZVex has been a regular here for many years. His schematics are not traded here, but the above link should get you started.

The thing to do would be to isolate the volume control of a theremin circuit and use that to control an LED/LDR or JFET that controls the actual effect.

[R.G.]

The general term for body position sensing stuff in the performance music/art biz is "gestural controllers". Try typing that into a search engine.

Theremin style field disturbance sensors can be used for generating a control voltage for any voltage controlled gizmo. There are also capacitive sensors, light sensors, etc.

[toneman]

try

"proximity sensor"

this is escentially what a Therman is.
Yes, it functions with a capacitance field,
which is electrostatic, not an electromagnetic field.
Also, oscilloscopes use electrostatic beam deflection.
And TVs use electromagnetic beam deflection.

"proximity" detection can B used instead of motion
sensors in a lot of cases.  Because, whereas motion
sensors only detect *movement*, Proximity sensors
detect the *presence* of an object.
So if an object is not normally supposed to B there,
sensor is active, alarm is triggered.
Don't confuse "proximity" with "touch switches".
Some touch switches use the 60hz from your fingertips.
(everybody's an antenna in the 60hz field)
(BTW, this are *magnetic* fields)
Other touch switches "drain" off the charge of a hifrequency
clock.  This is how Paia touch switches work.
One of Don Lancasters' articles has an "antenna" touch switch
circuit.   It just detects the 60hz pulses when U put your finger
on a touch plate.  A lot of these touch-lamps do this the same
way.  
Since the ZVex stopmboxes are "foot activated", they are
probably more proximity/thermin type in their operation.
A fixed frequency and a frequency that varies with the
object(foot) being near,  Produces beat frequencies,
sum and differences.  PAIA's Thermax turns this into
control voltages that U can use to control modular synthesizer
modules.  Moog, still in business, also has a gestural controller
on the market also.
I always wondered why no big manufacture figured out
how to eliminate the switch from the stompbox(?)

"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead

staytuned-without touching
tone

[Fp-www.Tonepad.com]

http://www.maxiespages.com/Articles/Theremin_tech/Circuit_diagrams_Related_circuits

That should drive an LED with minor modifications.

Fp

[crazybuilder]

it looks like i can build that circuit and i think it will work, but what kind of antenna can i use? Can i use a copper plate?

-J