[TriEmbed] TriEmbed Digest, Vol 39, Issue 18

[Alex Davis]

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> 
> If you decide to use 38kHz carrier, you will either use a lot of energy
> or
> limit your distance.
> Here's my suggestion:
> 1. set IR LED's current to 100mA or higher (up to 1A,)
> 2. send 1us-5us  pulses, 10 to 50 per second,
> 3. use pin interrupt and timer to detect and count missing pulses
> 4. use lens (LED) and IR filter (detector)

I wonder if you could adapt these cheapo microwave doppler sensors -
maybe mount them in a 'cantenna' to make them directional?

http://www.aliexpress.com/item/wholesale-HB100-5pcs-Wireless-Doppler-Radar-Microwave-Motion-Sensor-Module-and-microwave-motion-detector/545656348.html?ws_ab_test=searchweb201556_0,searchweb201602_5_10057_10056_10065_10055_10054_10059_10058_10017_107_10060_10061_10052_414_10062_10053_10050_10051,searchweb201603_7&btsid=f21587b3-a261-46b7-9e49-7bd3216a3d33

You've probably got to accept a degree of false positives with those.

Alex


-- 
"The theater of noise is proof of our potential."
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