Proximity sensor?

[Magnus Danielson]

From: Andrew Schrock <aschrock at cs.brandeis.edu>
Subject: Proximity sensor? 
Date: Wed, 29 Sep 1999 21:53:20 -0400 (EDT)

> Hi all, 
> 
> I am currently building a multimedia sculpture (video/sound). It is DIY
> related, actually, since it will have primitive mixing facilities, parts
> of a casio sk-5, parts of a speak&spell, and an analog filter. However, I
> know how to do all that.. my question today is: what do you think is the
> best way to implement a proximity sensor? I was thinking some sort of IR
> switch, but I've always had a bit of trouble with those being reliable. I
> need it to turn the sound on when somebody walks in front of it and go off
> when they walk away. Seems fairly simple, but it has to be rock-solid. Oh,
> did I mention cheap? :) 

Hmm... all this talk made me think...

If you swap over to EMS (yes, the same once's that did the VCS3 and Synthi A)
homepage you will find out that they are doing something which may be
interesting. It's not a theremin but in a way it takes in the same consept
of moving your hands through space.

While you are there you can question yourself on weither to get a new
Synthi after all...

Cheers,
Magnus