jez Smith wrote:
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Trouble is with a laser beam of 1mm diameter lets say,receiver100Meters away means that you need to align the transmitter/receiver to within 1/1000th of a degree otherwise the beam will miss the receiver.much better to use normal diode with a parabolic reflector,set the beam width to say a meter and you only need to be accurate to a degree

..and you need a 1 metre optic to make a 1 metre parallel beam ? If you forget beam divergence (and with a diode its huge), and allow for a target of say 5mm across, you have 3 thousandths of a degree to aim at...

Use a basic beam expander (telescope !), make it from spectacle lenses and you can do it over 100 metres easy, if you use decent detection electronics.


Steve
Steve