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beam intteruptor" indicator

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james

New Member
:roll: pls. help me make a ckt.-"beam intteruptor" indicator. An alarm should sounds when someone interrupts a more or less 10 meter single IR beam. It's okey if it requires 2 set of module, transmitter and receiver. I just want to be informed if somebody is at the entrance of our gate. Pls. just the simple ckt. not the sophisticatd one. thanks a lot.
 

pebe

Member
Infrared beam

If you're going to make a sensor as a hobby excercise, then OK. But if you just want an end product then you would do better to buy an infrared heat sensor as supplied for burglar alarms.
 

Ross Craney

New Member
IR Beam

With the effort of waterproofing , lens / focus and reliability ( no false alarms ) you would be better off buying a commercial unit .
( about $160 Aus )
 

mechie

New Member
IR Beam Alarm

I'm not sure on this one ---
Surely a box containing Tx and Rx directed at a mirror (glass or metal?) could be built for £20 ish UK pounds :?:

If the Tx is modulated at a few hertz it should be easy for the Rx to discriminate between signal and stray light. A 555 timer, 741 op-amp or two, some passives and a PSU :idea:

By mirroring the light back we double its travel distance (square-law = 1/4 strength) but a single PSU/cable/box makes installing easier.

:idea: Velleman do an IR beam kit (claims 4metre range) for £10 (their code MK120) or a few changes to their ultrasonic car parking alarm (code K3502) could make a useable cross-drive 'beam' detector ?
.... .... .... www.velleman-kit.com
 

bogdanfirst

New Member
or u could try something else, i did something like this one day, to knok when people were coming in.
the thing i used was a cheychain laser a mirror, a LDR and a simple circuit vith a beeper.....
the idea is that u dont need any modulation signal and with a quality laser u can have a gread distance, a few tens of meters....
to solve the daylight problem wuold be to use a small tube, and fix the LRD at the of it, something like this...

----------------------------- ___
====LASER beam====|O___LDR
-----------------------------

if u get it. when the laser light falls on the LRD it shrinks its resistance to less than 1k.
 

pebe

Member
I still prefer the IR burglar alarm sensor.

No fighting to get enough range. No setting up. No mirrors. Easy to interface, and reliable.
 

alagbary2000

New Member
can you help me
i want to connect ir burglar circuit to the parallel port of my computer and i can't determine the specefic circuit to do that
i want to help me ok
please send me your suggestion to [email protected]
 

philba

New Member
james said:
:roll: pls. help me make a ckt.-"beam intteruptor" indicator. An alarm should sounds when someone interrupts a more or less 10 meter single IR beam. It's okey if it requires 2 set of module, transmitter and receiver. I just want to be informed if somebody is at the entrance of our gate. Pls. just the simple ckt. not the sophisticatd one. thanks a lot.
person? car? dog? does this include opening the gate or just passing between the gateposts?

be aware that any beam break or PIR device will be prone to falses. any animal will set it off with no easy way to discriminate. If it's a vehicle you want to detect, then there are much more reliable ways to do it. if it's opeing a gate, there are also more reliable approaches.
 

akg

New Member
philba said:
person? car? dog? does this include opening the gate or just passing between the gateposts?

be aware that any beam break or PIR device will be prone to falses. any animal will set it off with no easy way to discriminate. If it's a vehicle you want to detect, then there are much more reliable ways to do it. if it's opeing a gate, there are also more reliable approaches.
man...the message was dated "20th October 2002" :)
 

akg

New Member
alagbary2000 said:
can you help me
i want to connect ir burglar circuit to the parallel port of my computer and i can't determine the specefic circuit to do that
i want to help me ok
please send me your suggestion to [email protected]
what is the type of o/p of the burglur alram , analog ? ttl ? .
 

philba

New Member
akg said:
man...the message was dated "20th October 2002" :)
yeah, i see that now. the one before my post was from today, though. I just assume he was trying to hijack a current thread. sigh.
 
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