Red Blinking Light Chicken Protector

I have more info on the "red eye"/niteguard.

I first saw one on the farm where I interned.  The farmer had been given it as a gift by a friend, but he didn't really have heavy predator problems.  What I noticed there is that there is nothing sophisticated about the device-- it is simply the common, red, self-blinking LED which can be picked up a radioshack for 50 cents or in bulk for even a lot less.

I rigged up from a solar garden light another one with 4 LEDs for my farmer/friend, though he still really didn't have much need for it!

Later that year I went to a "grazing conference" which included a farm walk in Florida.  They had a portable coop in a field following the cows but without any electric net fencing surrounding the birds.  On each side of the coop was one of the nite-guard units.  Their testimony was that before the nite-guards they lost a chicken once a week or so to foxes/coyotes, since getting them they haven't lost any.

Last year I rigged up a blinking LED near the chicken coop on our homestead here.  We haven't had any foxes or weasels invading our pretty shoddy fence to attack chickens in the old run down coop, but it might also be the proximity from the house.

I also made one up for a friend in the village who had dogs bothering his cows, and he said the dogs shied away from the blinking light.

Anyway, if you want to try it, rather than paying $25, you can buy a solar LED lamp, blinking red LED, plain red LED, plain diode with 0.6V forward voltage and resistor.  The driver circuit tries to maintain a constant 20mA or so current across the white LED, and doesn't play nicely with the blinking LED because when the blinking one is off, then it drives up the voltage as high as it can to push 20mA across an high resistance.  Then the LED turns on, and before the driver circuit can compensate, the high voltage and corresponding high current fries the LED.  The other LED with a plain diode in series effectively raises the total forward voltage, which means that when the blinking one is off, then current flows through the plain one, but the driver chip never has to push up the current too high.

Hmm... I guess if you're an electrical engineer, as I am, the above paragraph makes sense.  Otherwise, I really need to make one of those solar blinkie things for myself as well as its getting colder here which brings wolves and other things closer to use humans, so I can refine my experiments and give a schematic if anyone is interested.  Anyway, you'd be out about $4 max (assuming you have a soldering iron) to give the device a try.

I would like to see the plans, and the finished product.

Thanks

what if you just took a white led garden light and soldered a red led in line with a resistor of the correct value?

Casey Halone wrote:
what if you just took a white led garden light and soldered a red led in line with a resistor of the correct value?

The garden light has an LED driver circuit that will drive the voltage up while the self-blinking LED is off in attempt to keep ~ 20mA of current through the LED.  When the LED switches back on, the driver circuit doesn't instantly compensate, so most likely the blinking LED will quickly die from stress, which was my experience at least.

(I wrote a much longer reply, but then the computer crashed).

Attached is a schematic for a circuit I tested, assuming 5V input.  I don't have time at the moment to tear apart a garden light for this, sometime later I will.

Basically, you use the normal green and red LEDs in series to give a forward voltage there of 4.2V, whereas the two red LEDs (one blinking) have a combined forward voltage of 4.0V.  Current will mostly flow across the LEDs with the lower forward voltage drop.  So when the blinking red LED is on, then it flows through that path, but when it is off it flows through the other path.  You need only one resistor, in the position shown (or oppositely at the negative side).  100 Ohms is probably higher than needed, but you'll have to experiment.  There may already be a resistor in series with the white LED.  My advice is to start with 100 Ohms and work down from there, bearing in mind that if too low, the LEDs will fry.

Make sure the battery is disconnected and solar cell is covered when connecting in the new LEDs, or there will be again the condition of the driver circuit driving up to a high voltage trying to push current across an open circuit.

I use 4 LEDs here and drilled holes in the garden lamp so each LED was 90 degrees from the next one facing out, so that at least one LED should be visible to a predator from any direction.  If you really wanted just one LED like the commercial product, then you could try putting enough series-connected plain switching diodes in parallel with the blinking LED.  The key is that current must always have a path to flow with nearly the same forward voltage drop.

Sorry if some of this isn't totally clear, it is the middle of the day here, so I need to get out and work rather than type...

Technical electric wizardry aside this sounds really interesting - do the predators get used to the light ?

Can someone say why they work? What causes predators to stay away from the blinking light?

Also - for those less gifted electrically - I'm pretty sure they do red "berry type" Christmas tree lights that flash, is more lights better ?? I'm not sure I want the hen run lit up like a christmas tree but if it keeps the foxes off I guess its worth the growing reputation for eccentricity around here !

In my part of the world we have reflectors along the side of the roads in deer country that reflect the car lights and scare deer back from the road, so less danger at night. The reflectors are supposed to mimic the eyes of a wolf, I find it interesting that the LED's keep the fox's away, has anyone got any research on these?

Kirk Marschel wrote:Can someone say why they work? What causes predators to stay away from the blinking light?

I'm a person that questions any claim that sounds weird to me, so I looked this up. Apparently flashing lights in general can scare animals- It doesn't have to be an LED or red in color. (aren't most animals color blind anyway?) sounds, metal pie pans, motion activated water sprayers,etc. are all things that startle animals and it seems to me its the unexpectedness of their action that makes them work.
I would think that animals might get used to something after a while though, but the reviews of the flashing red lights on ebay, amazon, etc. mention using them for up to a few years with no problems.

I have some solar powered Christmas lights shaped like regular path lights that alternate between blue, green and red.
I never bothered to take them out of the yard after Christmas, so maybe I will just leave them up the rest of the year and see if I have deer in my garden
this season.

the reviews on Amazon are filled with folks who tried this and it didn't work. It seems like raccoons are especially immune to it, but also skunks, cats, and deer.

Amazon Reviews

I wonder if it is because these animals are so used to humans and human devices. Maybe it would work better in a rural environment, but in the suburbs, it seems to be less than effective.

We have used these in various places around the yard for over 10 years. They were originally developed to protect fighting cocks out on tie cords from predators. The key to sucess is having them at the right level -- they need to be about eye height for the predator you are trying to warn off. They also have to be all the way around the perimeter. If you only have one, the predator will go around and come in from behind. Cover all 4 sides, the more the merrier. Since we have been using them, no raccoon, feral cat or skunk attacks on the chicken pens and we were losing birds every week until then (and it has kept rabbits out of the garden). For deer, they need to be higher - and having CDs on fish line hanging about that reflect the blinking red light seems to reinforce it. For owls, place the lights even higher. A 20 ft pole set up in the yard with one on each of 4 sides can reduce owl removal of tree roosting birds amazingly. Doesn't seem to bother the chickens or the tree roosting birds, it may make them hold very still if they think it is a predator. Just as a precaution to keep critters from becoming used to seeing the little red "eye" I move them around at random but keep them the same height. The only thing it doesn't seem to phase is opossums, I don't think they have enough brains to be affected but that is only my opinion. I have trapped over 18 possums this year trying to get into the chickens but none of the other predators. Learning how to make the lights from radio shack parts would be waaaaaay cheaper. Great idea!

Cris Bessette wrote:

I have some solar powered Christmas lights shaped like regular path lights that alternate between blue, green and red.
I never bothered to take them out of the yard after Christmas, so maybe I will just leave them up the rest of the year and see if I have deer in my garden
this season.

Might keep the whitetails away but you may want to watch out for Reindeer! HA! Don't go adding jingle bells anywhere or you'll really have trouble.

lol

Craig Dobbelyu wrote:

Might keep the whitetails away but you may want to watch out for Reindeer! HA! Don't go adding jingle bells anywhere or you'll really have trouble.

lol

so you think it would actually attract reindeer instead of repel them? Hmmm.... I could make part of the yard into a santa landing pad.

The way Marsha explained it seems more realistic means. I have used 1 blinking red led light to attract and catch predators, not canines (too wary) but it will definitely attract cats (it is a common method of catching bobcats in live traps)

Bad news:

I tried actually making my circuit again. The driver circuits inside the lights I've bought have been simplified, and simply don't work with that circuit.

Right now I don't have time to pursue making a circuit that would work.

Basically, there are 3 approaches:

1. Combine solar cells and batteries from two lights to get 2.4V instead of 1.2V and directly drive blinking LEDs. This has the distinct disadvantage of needing a new housing...

2. Drive standard LED from the driver circuit, placing an oscillator circuit in between the driver and battery.

3. Throw out (or at least into that drawer where you keep random bits of electronics) the driver circuit. Replace with http://home.cogeco.ca/~rpaisley4/LM3909.html

Probably number 2 will work out to be the least complicated.

Right now, I have a zillion things to do (like re-roofing) and my wife would kill me if she caught me fiddling around with electronics.

In the meanwhile, RadioShack 276-299 Bright-Red Blinking LED Module is $4 plus 2 AAs, so you can get four of them for as much as one solar powered commercial device, and test and see if the blinking LED concept will work against your predators.

Also, if you don't need the flasher tonight, just buy blinking LEDs, resistors, and 2 x D battery holders and D batteries online. That combination should blink for months without needing to change the battery and you can make more than 4 for less than $20.

Roger Merry wrote:Also - for those less gifted electrically - I'm pretty sure they do red "berry type" Christmas tree lights that flash, is more lights better ?? I'm not sure I want the hen run lit up like a christmas tree but if it keeps the foxes off I guess its worth the growing reputation for eccentricity around here !

as a naughty neighborhood boy, i would run around at night around christmas time and remove individual lights from light strings, so if you dont want it to light up like a tree, maybe just remove all the lights you dont want?

idk how this would affect the stress on the other lights though

also for anyone who is afflicted by such naughty neighborhood kids, thye may be willing to just give the strand to you for free, i think a lot of them may just throw them away anyway