I volunteer with a group that catches feral cats, spays and neuters them, then returns them to the colony. We’ve used the live traps you’re probably all familiar with, but the vet involved in this is looking for a better way since sometimes the mechanical traps don’t close fast enough to keep the cat from bolting.
He knows i wire my own houses so he asked if i had any ideas for one part of the problem that’s holding him up. I don’t have any electronics experience, so i said i’d turn the problem over to the BT Brain Trust.
The idea is to make a trap so that when the cat’s head breaks the infrared beam across the food bowl far inside the trap, a mechanism slams down the gate before the cat can turn around and escape. Mechanical models rely on the cat stepping on the pan holding the food and releasing a spring loaded gate.
Attached is the schematic the vet sent me. If more information is needed, let me know and i’ll ask him. Thanks for looking at this for us.
Replies
Interesting problem. Wish I could help ya.
You should get lots of input here, since there are a lot of guys on the board. And guys are ALWAYS chasing.....................Cats.
(-:
Some automatic gates have a beam of some sort, that keeps the gate from closing, if the beam is broken.
There is a small box on one side of the gate that transmits the beam.
A reflector on the other side.
I'm sure this could be used to trigger the trap, instead of keeping it from triggering.
Triggering the trap by breaking the beam is the idea, as the cat head interrupts it when it reaches for the food bowl. It's the part about blowing the circuit that the vet (Alan) is having trouble with...and i unfortunately don't know enough about it to re-state the problem any other way.
Hopefully Junkhound will stop in. I'd bet he'd have the answer.
Did not read the rest yet, but use a FET, a generic IRF150 will easily work and is great overkill (pun intended). With a MOSFet, you can simplify the circuit also, looks like something from the 1950's.
Can be a VERY simple circuit, forgot to add the avalanche diode voltage - anything between 7 and 18 volts is OK.
Cat paws complete the gate circuit to the FET, FET (IRF150) turns on solenoid, gate drops. Cat wont feel the 9V battery unless feet are cut and in salt water.
Edit clarification - drew this fast, this will not automatically reset as shown, need to add a few megohm gate to source resistor to the FET. With that, solenoid will turnoff if the cat lays down on it's fur or is not stepping on both contat pads simultaneously-
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Edited 11/6/2008 11:23 pm ET by junkhound
The vet's plan is that the cat's head breaks an infrared beam to trigger the solenoid. The traps are often in wet areas because we're catching ferals, so they get shoved under trailer houses and in barns...all kinds of places that could get rain or ground water, so the [wet] paw thing wouldn't work. They're very quick learners, so if we zapped a few, even by accident, i believe our trapping rate would fall way off.<G>Beyond that, i have no idea what the vet is asking to be fixed in his schematic or why his idea isn't working; i'm merely the messenger.Please, sir, may i have another...schematic? Thanks!~Splintergroupie
These guys?...The unspoken word is capital. We can invest it or we can squander it. -Mark Twain...Be kind to your children....they will choose your nursing home....aim low boys, they're ridin' shetland ponies !!
All right. Which one of you said cat trap?...The unspoken word is capital. We can invest it or we can squander it. -Mark Twain...Be kind to your children....they will choose your nursing home....aim low boys, they're ridin' shetland ponies !!
so three days later this is what showed....
a way cool cat.....
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Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
This is a nasty cat. A black bobcat caught by the Florida Wildlife Servicehttp://esteroriverheights.com/wildlife/fwcblackbobcat.jpg
that looks more like a panther...
there's a pair here now (bobcats) that are fearless and agressive....
we shall see...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Thank you.That's three days I don't have to sit and twiddle my thumbs.Cool cat.
somebody else did it and mailed it to me...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Well thank you to both of you, then.=0)
The more I read of this thread the more I think you should stay with a mechanical trap and just fine tune that. I had the same issue with a rat trap I built and just increasing spring size and making them work a little harder for the bait worked fine.http://esteroriverheights.com/wildlife/rattus_rattus.jpg
Just electrify the trigger plate. Not a single cat will get away.
That'll save a lot of time and trouble in alternations, too! <G>
You can get SCRs that are good for hundreds of amps. I dobt you need any kind of buffer transistor at all. Radio Shack has them in the 5-6a range. Put a diode across the coil to clamp the back EMF
Greek to me, but i'm copying the thread and passing it on. Thanks for the input.
You should put switch in there to open the coil circuit once the trap is sprung to save your coil and your battery. That is when you need that diode across the coil.
Keep the ideas coming and i'll be the courier!
I think you win the prize for most interesting/wierd request on BT this year.
I have nothing constructive to offer other then good luck... all a bit above my head.
Unfortunately, it's been about 20 years since I dabbled around in that stuff. Otherwise I'd possibly have an idea.
But I'll take another peek and see if anything comes to mind.
Any help you can offer is most welcome.
For a small solenoid wiring directly from the open SCR connection to the open solenoid connection would seem likely to work. You'd have a better opportunity of success, though, if you placed a small "DIP" relay in place of the SCR as described above, then powered the solenoid off of the relay.
Something like this:
Let's try that again:
Conscience is the still, small voice which tells a candidate that what he is doing is likely to lose him votes. --Anonymous
Run current thru trap to stun it, than the cat isn't quicker than the door.
Mmmm, 480v should do it.
200 lb Rottie
Edit: OK, it wasn't just me being blonde! Got it on the second try.
Edited 11/5/2008 2:00 pm by splintergroupie
can a cat see infrared? I thought that some animals do and if so will this be a detractor? something to do with the tapetum?
I guess we'll find out if they can see it, and if they can, whether it matters to them. Good question, for sure.
PS: If this works out I have some cats to try it on.
Electronics aside, would a faster-stronger spring on the door release work? Maybe gently punt the kitty back in.
I wonder if there's some other trap with a greater distance from door to bait?
So what's it like to transport one of these things when you get one? Does the cat go nuts or do you knock it out first?
Everything will be okay in the end. If it's not okay, it's not the end.
use the reader from an overhead door and a selinoid...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
How about some sort of capacitive discharge device, sorta like a "cat stun gun," that would freeze em in place for a short while to allow the trap doors to close?
way too complex.. sort of like NASA spending a fortune making a pen that would write in zero gravity and the Russians simply used a pencil.
Door not fast enough? Simple, make the cage bigger! So the cat takes more time getting back to the door and gets trapped.. that way you don't have to lpug in things and deal with electical failures etc..
KISS (keep it simple stupid)
I have had pretty good luck catching feral cats using a HavaHart mechanical trap. I don't remember the exact model but I think it is a model 1092. If you are putting the food on the trigger plate that might be the problem. I tried that at first but I had much better luck placing the food on the back side of the trigger plate so that the animal (cat) will need to step on the plate to reach the food on the other side. Placing the food that far back will get the cat further into the trap and prevent them from being able to get to the food without setting it off. Assuming that your trap is only open at one end.
Your cats may be smarter than the ones we have around here so it may not work... but it may be worth a shot.
Steve
I suppose it wouldn't be easier to find some feral dogs to keep the feral cat population down?
jt8
The creative individual has the capacity to free himself from the web of social pressures in which the rest of us are caught. He is capable of questioning the assumptions that the rest of us accept. -- John Gardner
Then you'd need feral tigers for the feral dogs. It just never ends.
Conscience is the still, small voice which tells a candidate that what he is doing is likely to lose him votes. --Anonymous
Let me guess.All this started with a feral fly...
Then I guess we need to work a goat in there somewhere.
Conscience is the still, small voice which tells a candidate that what he is doing is likely to lose him votes. --Anonymous
Can't.Dovetail hid it too well.
Ever see a dog / cat fight? Dog leads with its mouth, directly below the nose and eyes. Cat claw in either one really dilutes the dogs agenda.
Howdy, boys and girls. I just wanted to say thanks for the effort and the emails helping me with this. Don't you just love technology? <VBG>
I hope that's splintergroupie who's figured out the trick to avoid the whiners..
Translating screennames to their real persona is like learning a second language...;)
The circuit you have as drawn is incorrect. The 10k resistor from the emitter of the 2n2222 transistor should go to ground. The trigger of the SCR then should be connected to the emitter of the 2n2222 transistor. The output of the SCR should be connected to the bottom lead of the solenoid. The circuit works thusly: The Infrared beam shines on the photo transistor and turns it on. The conducting photo transistor then has a very low resistance in the on state and that means that the voltage at the bottom of the 100k adjustable resistor will be very low and not high enough to turn on the 2n2222 transistor. When the IR beam is broken and the photo transistor shuts off, voltage at the bottom of the 100k resistor will rise and turn on the 2n2222. The 2n2222 in the on state will have a low resistance and hence the voltage at the emitter and top of the 10k resistor will rise to towards the 9 volt supply. This positive voltage will trigger the SCR to turn on and conduct thru the solenoid. This circuit will not reset until the power is removed and reapplied, so the solenoid will continue to be pulled in.
It's Greek to me, but that sounds very authoritative and i'll pass on the info to the vet so he can modify his set-up. Merci!~Splinter