Security Idea

[Acetronics2]

Hi, Koossa

Dogs, Lions, crocodiles moat, Geese ...

but Cheap technology won't make it for a 6 to 8 Km long fence ...

Alain

[Jumper]

To start with you would only need to get 1000 m range of the RS-485. That is of course if you put the main controller in the middle of the 2000 m fence :-)

And with a low baudrate you can get up to 4km I think... so this should not be an issue.

When it comes to IR led a normal TSAL6100 can be modulated with i.e 40kHz to get a carrier that fits a normal TSOP4140. You can of course have any carrier fq but 33k 40k and 57k are common. Then you send data on this carrier in short burst. Short enhough to be able to drive the led really hard 500mA or something and short enough so you don't overheat it.

A good guess would be that intruders are more common during night time than daytime and so getting 50m is not that hard. After 50m there is a receiver and a new LED and so on.

If you would like to try a normal magnifying glass attached at the end of a pipe is a good start. To get 50 m you would need a 25-50mm diameter and a focal length of atleast 150mm to make it work during daytime.

If you need more info you can PM me

[Melanie]

Buy a Dog or two ... and I don't mean a Pekinese or a Poodle either!

IR Beams can easilly go for 100m or more... but are tricky to set up... the professional one's are best because they have vernier adjustment on the mirrors... a fraction of a degree at 100m or more means you miss alignment on the target.

Try running a voltage through the razor wire (a few kV would do)... PIC can then detect if it's been cut.

[koossa]

Hi Jumper

Thank you very much for your feedback!


Melanie, I like the "power through the razor wire" idea, but the only problem is how do I detect which zone it has been cut?

[Jumper]

With enough kW there would be smoke from the person cutting the wire...

[mister_e]

Or the local skateboard shop will increase sales

[koossa]

How difficult is it to communicate over a 50m IR connection?