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Electronic Trip Wire

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hi Paul,
I go with Torben on this one.:)

I have looked at the dwg you posted.

Alignment of the laser beam passing thru four corner mirrors is going to be a major problem, especially as you have two beams.

Even during installation if you can align the system, the smallest movement of the pillars holding the mirrors will misalign the beam.

The other problem is keeping the mirrors free of dust, spider webs and bugs.

In desert conditions heated air layers will cause refraction of the beams.

A couple of African Ridge back dogs would be my solution.:)

hi Torben,
Was it ignorance that let the cat out of the bag or curiosity.?;)
 
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hi Torben,
Was it ignorance that let the cat out of the bag or curiosity.?;)

Morning Eric!

In this case, ignorance, I think. Which is good, because ignorance is curable--we all start out with it. Stupidity isn't curable, and neither is curiosity. ;) Luckily Paul appears to have curiosity but not stupidity.

I think Paul meant to have a receiver and a transmitter in each post, and not use mirrors. That would make aiming easier. It would still need some upkeep to maintain the beam paths though. I still think a real fence would be more reliable though.


Torben
 
Morning Eric!

In this case, ignorance, I think. Which is good, because ignorance is curable--we all start out with it. Stupidity isn't curable, and neither is curiosity. ;) Luckily Paul appears to have curiosity but not stupidity.

I think Paul meant to have a receiver and a transmitter in each post, and not use mirrors. That would make aiming easier. It would still need some upkeep to maintain the beam paths though. I still think a real fence would be more reliable though.
Torben

hi,
I suppose it may be feasible to have a simple wire fence, say two insulated strands, one metre above the other
and feed them with a hf low energy signal and to monitor the inter strand coupling and to ground.

Some fish use a similar method for prey detection.???
 
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hi,
I suppose it may be feasible to have a simple wire fence, say two insulated strands, one metre above the other
and feed them with a hf low energy signal and to monitor the inter strand coupling and to ground.

Some fish use a similar method for prey detection.???

If I get what you mean, is that just sensing the presence of a body through its interference with the RF field? If so, neat idea. :) I wonder whether vegetation might need to be kept clear though. Then again, in a desert, vegetation is usually either really small or really slow-growing, except maybe in the rainy season. Then again, I don't know what effect vegetation would have on it.

You could hook the thing up to loudspeakers and an audio playback device. Scare the heck out of someone who hadn't even touched the fence yet.

"Please step away from the fence. You are being monitored."


Torben
 
If I get what you mean, is that just sensing the presence of a body through its interference with the RF field? If so, neat idea. :) I wonder whether vegetation might need to be kept clear though. Then again, in a desert, vegetation is usually either really small or really slow-growing, except maybe in the rainy season. Then again, I don't know what effect vegetation would have on it.

You could hook the thing up to loudspeakers and an audio playback device. Scare the heck out of someone who hadn't even touched the fence yet.

"Please step away from the fence. You are being monitored."
What if he dosn't speak English.?;)

Torben

hi,
When do we start.:)
 
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