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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