Proximity sensor?

[David Halliday]

Hi Andrew!

Sounds like a fun project - have you looked into the cheap "home security
lights" that sell for $15 or so in local warehouse Home Depot stores?  These
run two floodlights and an electronics pod with an IR sensor.

The IR sensor usually runs fine on 12 VDC - get a unit, bust it apart and
trace the wiring - there is usually some kind of voltage drop ( often a
capacitor ) and then some regulation - use a meter to see what the final
voltage is and use that.  The output to the triac to switch the lamps is
through an opto-isolator.

Disclaimer - the guts of the circuitry have ZERO isolation from the 120 VAC
coming in so take precautions and isolate yourself accordingly - don't work
alone.


----- Original Message -----
From: Andrew Schrock <aschrock at cs.brandeis.edu>
To: SynthFolk <synth-diy at mailhost.bpa.nl>
Sent: Wednesday, September 29, 1999 6:53 PM
Subject: Proximity sensor?


> 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? :)
>
> Also, if anybody has one of those old Apple IIGS monitors, please let me
> know. (the REALLY SMALL green kind which takes composite video input) I
> need one, and the week I decided to go through with this project somebody
> bought the one I had my eye on at the salvation army. Bugger!
>
> later
> Andrew
>
> -| Andrew Schrock | aschrock at cs.brandeis.edu |-
>
>