Long distance IR beams interfaced to RS485 based alarm system

[backspace <sawireless2000@xxxxxxxxx>]

Long distance IR barrier beam:
Use a http://www.roithner-laser.com, http://scratchpad.wikia.com/wiki/InfraRedLeds
parabolic 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. http://www.kemo-electronic.com 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
http://scratchpad.wikia.com/wiki/RS485 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 http://scratchpad.wikia.com/wiki/ConfiguringAlarmSystem and
http://scratchpad.wikia.com/wiki/SecuringPerimeter