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Topic: Best way to detect coming & going? (Read 554 times) previous topic - next topic

Pauly

I currently have a Maxbotix Ultrasonic Rangefinder - LV-EZ1 hooked up to a wave shield.  When someone enter the room it plays a sound.  I want to detect when someone leaves the room as opposed to entering it and play a different sound.
I'm assuming I'll need two sensors where sensor a is closest to outside the room and sensor b is on the inside.  If sensor a is tripped first then play sound a.  If sensor b is tripped first, then play sound b.
What is the best way/ sensor combo to go about this?  I'm open to using any sensor.  

fdufnews

Your rangefinder returns you a distance?
So taking a few measures you can compute:
  - If the distance is decreasing the target is entering the room
  - If the distance is increasing the target in living the room

MikMo

Of course they could be moving around in the room, and in that case you would not know.

A better aproach would be to have two sensors, IR beams or similar, and then check the order the beams was broken. 1 firs t then 2 = enter room. 2 first then 1 = leaving room.

Pauly

Thanks, I'll order a couple of IR emitters & detectors from  Sparkfun.

Also, what is the best way to detect someone is standing directly in front of something hanging on the wall like a map?

Would a Sharp Infrared proximity sensor work?

I'm attempting to "animate" a room. Standing in fron of the map would turn a light on.
;)

digimike

The range finder would be perfect for the map idea. Have it mounted over the map and pointing down in the are you want it to. They can also work on the doorway for entering and leaving. Just have them pointing straight down.

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