Laser Perimeter Alarm
Hello all,
My mum would like a perimeter alarm system for her farmhouse to notify when someone enters via either driveway. I was thinking of using a remote unit housing a laser diode, oscillator and 3V lithium primary cell, with the laser being driven with 10us pulses every 50ms (average current 22uA for ~10 year operation). The detector will be a simple reverse-biased photodiode w/ AC amplifier.
So, the question is, does anyone know if (in general) cheap chinese laser pointers (<~1mW) can be switched on/off (and actually lase) in 10us, what their forward voltage is, and what current can they handle before destroying themselves? I know the diodes will vary between manufacturers, but was still curious if anyone has had any experience with any.
Total beam distance is ~100m, with a mirror somewhere around halfway to redirect it towards the house; hopefully the beam doesn't diverge too much.
Hello all,
My mum would like a perimeter alarm system for her farmhouse to notify when someone enters via either driveway. I was thinking of using a remote unit housing a laser diode, oscillator and 3V lithium primary cell, with the laser being driven with 10us pulses every 50ms (average current 22uA for ~10 year operation). The detector will be a simple reverse-biased photodiode w/ AC amplifier.
So, the question is, does anyone know if (in general) cheap chinese laser pointers (<~1mW) can be switched on/off (and actually lase) in 10us, what their forward voltage is, and what current can they handle before destroying themselves? I know the diodes will vary between manufacturers, but was still curious if anyone has had any experience with any.
Total beam distance is ~100m, with a mirror somewhere around halfway to redirect it towards the house; hopefully the beam doesn't diverge too much.
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