Long distance IR beams interfaced to RS485 based alarm system

Oct 13, 2007 4 Replies
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Long distance IR barrier beam: Use a

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reflector for IR beams to extend the range of the beam. The parabolic reflector focuses the IR beam of the diode installed inside the it.
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Infrared led kit has a range of



50m using a magnifying lens placed over the receiving IR-led. Combining a parabolic reflector lens to transmit to a magnifying lens at the receiving end will extend the range of a barrier beam to 100m. The Kemo Kit nr.b213 #24-194 only has a magnifying lens over the receiving IR diode and achieves a distance of 50m. Elektor Electronics p.55 and p.19 July/August 2002 has a design idea on building an IR barrier circuit.

Order the passive components and pay somebody in China to hand assemble it in bulk. Connect upto 400 of these cheaply built IR beam modules around every window and doorway and interface it to

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circuits for our custom designed alarm system. Each RS485 node connects an ARM processor which monitor the N/C condition on its port as close as possible to the IR circuit, PIR or contact switch.



See

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and
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Sorry, that's just not an option.

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For you, yeah... the Chinese don't speak Portuguese.

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The fatal flaw with radio communication is spectrum jamming. If you cut the phone lines the GSM radio will kick in. But if you use
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- there goes the GSM link.

One should try and run

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wires or even
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twisted pair to all the nodes and have some permanent
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backup system to stream to a distant premise alarm data in real- time. The mesh networking the wiki refers to is the
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protocol it contains over 400 page on installing and operating an Ad- hoc mesh. Zigbee for example uses some ad-hoc mesh protocol.

The only alternative to phonejammer on the GSM spectrum is to build your own

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GSM modem by hacking the patents that detect spectrum jamming.

The present alarm systems with all their cryptic input panels is a joke. We need to use an embedded ARM processor running Linux and Python that accepts a text file or some XML standard.

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The fatal flaw with radio communication is spectrum jamming. If you cut the phone lines the GSM radio will kick in. But if you use

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- there goes the GSM link.

Fortunately, there just aren't that many people out there using jammers to block a neighbor's lighting control system.

Not really. Although a skilled person with the right tools and prior knowledge of the system in use at a given property could get through, most residential users need not fear. The guy with the right talents and the right gear will set his sights on bigger targets.

Build one and I'll market it.

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