see:
http://techref.massmind.org/io/sensor/meat

(you know, people are mostly meat...)

---
James Newton mailto:jamesnewton@geocities.com 1-619-652-0593
http://techref.massmind.org NEW! FINALLY A REAL NAME!
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-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Mauricio Jancic
Sent: Thursday, March 30, 2000 18:46
To: PICLIST@MITVMA.MIT.EDU
Subject: [OT] people detector, cheap, low consume, and esay to build, is
that too much?


Hi people,
        I'm looking for some ideas on how to make a "people detector". The
idea is to make a device that plays a pre-recorded voice message (ISD14000
series) each time someone is in front (or near) it.
        At the first time, I was thinking on a Datalogic infrared sensor
(abou U$S 120 + 21% (taxes) here in Argentina). But there were two problems:
1st.  The high price in relation to the rest of the circuit.
                                                2nd. As it must be battery
powered i make some calc on the total consume and it was too much for me.
According to specifications the sensor consumes 25 to 30 mA (the same that
the isd when playing) and that get's me to a 2.5 weeks with a 12Ah and 12 v
battery.

                                                3rd. It isn't very nice to
put such device on this simple circuit.

        So, wath im looking for is some bright and ease to build ideas on
infrared or ultrasound "spectrum".
        Do you have any??

        Thank in advance, Mauricio.