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Motion sensor

daviddoria

New Member
I saw in the projects forum an audio sensor... what i need is a motion sensor. this project is designed to keep the deer from eating our flowers. I bought a little factory made one, but it is unidirectional and it only works about 4 feet. i was thinking something like omni directional and like 10 feet. how would i go about this? IR?

thanks
david
 

bogdanfirst

New Member
maybe ir, but whay dont you try a presence sensor better?
you kmow, like a PIR or maybe someting to detect the presence by induced current.
 

daviddoria

New Member
haha never heard of that...
i searched for "presence sensor" and "PIR" and found nothing. can these be built or do they have to be purchased?
 

daviddoria

New Member
i can't seem to find a "PIR" as a component, rather as a fully assembled device for $40. can i not use a normal IR LED and a Receiving IR LED to get the same sort of effect?
 

bogdanfirst

New Member
they look like transparent leds or black leds,3 pins, from 5 to 20 mm, depending on range, this is what i found out from someone that works at an alarm company, but i think it is quite hard to find them as components....
2 bad i needed them too.
but i dont thing that you can use an IR led, because it will sense ambient light and any sourcce of heat, even a flashlight, or even a key chain laser, but i dont think deers use lasers :) :lol:
an alternative is to make an oscilator, LC, and attach a long wire to the "hot" wire, the connection from the cap and the coil and someone going around the wire will caouse the osc to stop oscilating or change the frequency, wich will cause the trigger.
you will probably ask me how to do this...well, i dont know, i just know the theory.
if i remember well i have something like this in a book, but it is very old, with Ge transistors, and you have to make the coil yourself....
1 turn, 2 turns, 3 turns.........
you get the idea, ill search the 'net for more.
 

bogdanfirst

New Member
nice idea the one with the satirs. but it could be better if it could be extended......the range, have something like 10 meters.
 

hsvgtsr1

New Member
pir's are no good outside no matter how good or how expensive they are because the sun or wind or any other animal can set it off. It is best to use a long range yard beam unit as they are not affected by these elements they need to be set up about body height of the animal. As a security technician these units usually cost about $130 aus for me. best go to a security shop.

cheers
 

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