Hello gurus,
I am looking for some form of motion sensor that will cover a much larger an area than a PIR and be more tolerant to natural light. I would like to cover the perimeter of a rather large area outdoors (4 hectares / 10 acres) and PIR just doesn't scale.
Any ideas on what might work well for this? I have looked at active infrared and radar but not sure radar would have the range of more than 20 feet.
bT
Some idea of what you want to do would be useful.
Are you looking to detect something entering the area, or any motion in the area?
What size objects are you interested in? Mice or elephants? Living or not?
How fast will the objects be moving? Very slow objects and very fast objects present unique challenges.
Can you give a sketch of the area (square circle triangle, more complex?) and if something is growing there?
Case border control: laser fence thing ???
Case area control: Movement detection based upon camera-images (webcams)
my 2 cents ...
Sorry, that was a rather vague description. The kind of description I often chide others for...
My neighbor raises Alpacas and he would like to monitor the perimeter both for his own critters escaping but also for predators entering his pasture.
The land comprises a large rectangle. He also owns the land surrounding the pasture which contains crops.
My thought was to either montor the property outside the 10 acre pasture for movement or monitor the fenceline between crop land and pasture.
bT
bitTwiddler:
Sorry, that was a rather vague description. The kind of description I often chide others for...My neighbor raises Alpacas and he would like to monitor the perimeter both for his own critters escaping but also for predators entering his pasture.
The land comprises a large rectangle. He also owns the land surrounding the pasture which contains crops.
My thought was to either montor the property outside the 10 acre pasture for movement or monitor the fenceline between crop land and pasture.
bT
I have thought of a couple of ways you could do something, but in the end, neither seem cheaper to me than building a 6-8 foot high (or higher - depending on whether and how high the alpacas/predators can jump) solid panel metal fence around the entire area.
One of the ideas is basically a ground radar system in the middle of the pasture (think a system like that used for ground control at airports) - not cheap at all. The other would involve so much custom design, coupled with the labor costs to install it, along with likely constant maintenance - and you'd only be able to tell whether something was leaving or exiting the perimeter (within a given section so you'd know approximately where the breach occurred).
I'm almost certain "solid" (I'm thinking something like perforated stainless steel or aluminum paneling - to allow airflow and light, but without holes big enough for a predator or alpaca to enter/exit) fence is the better and cheaper way to go...?
Funny how they want to know all the intimates then give you nothing
I am not familiar with anything that would cover that distance except a good quality electric fence with say 3 live and 3 earths between on galvanised star pickets .$10 per 7Ft6 picket
5 Meter spacing would cost $10,000 for 1000 posts alone for 4 Hectares.
Allow $300 for a good unit and $500 wire. Now that tends to keep the two legged morons out too. Should cost less than $11,000 all up -and thats new. It would be cheaper than any other alternative fences I would say
Sure hard to beat the human eye and brain . I'd set up a chair where you can see it all and have a beer .If they get out you will be so blind it won't matter
Ok tytower, I can see how the electric fence will make them move, but how do you sense that movement?
I wasn't looking at movement .
He wants to keep them in and others out
My neighbor raises Alpacas and he would like to monitor the perimeter both for his own critters escaping but also for predators entering his pasture.
When a beast earths the fence I have seen somewhere a system to give an approximate distance the pulse has travelled from the source based on time . But I don't know where that might be now
you can use a doppler radar motion sensor, can determine speed of object too.
It is not obstructed by light or weather, and it will even go through walls.
X band I think is 30 meters working distance and K or other band is like 100 to 300 meters
Funny how they want to know all the intimates then give you nothing
Perhaps because there is nothing to give. If such a sensor was readily available, for $2 at Radio Shack, it would most likely be common knowledge, and it would not be necessary to ask here.
Since the original post provided very few details, it was necessary to ask. The details have proven that the desired sensor either does not exist or is prohibitively expensive.
None of your ideas directly address the problem, either.
Moderator: slightly edited for content. Please keep it civil.
I see no issues yet with civility but the question of detail:value ratio does come to mind 
A solid fence 6' high for 10 acres would run about US$65,000. Those quotes are two years old so perhaps more if it were installed today.
I like the K-band idea. I will look at that again. I am also going to trial active infrared. There are many bison ranchers in the area that have similar issues. Certainly not predators but bison seem not to notice fences and routinely take down substantial barriers. The cost of one bison could pay for a breach detection system.
I'll post updates to my trials next weekend.
bT
I would think 4 or 5 parallel higher powered IR pulsed laser emitters at say 1 foot heights with proper optics, corner reflectors, and detectors would give the best price/performance ratio. At least if only detection and alarming are the main goals.
Thank you Retrolefty. After a bit of digging I am leaning that way as well.
If you have any recommendations on vendors, etc shoot me a line. Otherwise, I'll post back shortly.
bT
Hi,
What solution did you use until the end ? What sensor ?
BR
Daniel
My two cents worth:
It has been suggested a high power IR beam and reflectors......
Another option would be a laser around the edge of the fence.
Reflectors - as with the other idea - and a sensor.
If anything breaks the beam, the alarm goes off.
Yes you probably will get a few errors, but maybe make it multiple beams a good distance apart so grass can't break ALL/BOTH beams.
Then if an animal walks through the beam/s the alarm goes off.