Our property has a rat problem. My goal is to build a powerful electric zapper that kills them by electrocution. The electrocution mechanism will be bolted to the top of a 55 gallon drum that's half-filled with water. After the rats are zapped they will drop into the water, and if any survive the initial shock they will drown.

I would like to use 110vac as my power source, not only for reliability but also to eliminate the issues of battery charging and/or replacement. However, since DC is reportedly more effective than AC in this application, I'm thinking that I should rectify the AC voltage to DC before charging a capacitor that would deliver the lethal shock to the rats when they complete the circuit with their feet on a steel pipe and their tongues touching the bait.

I would like the final circuit to work consistently for years or decades, and I want it to kill instantly 99% of the time. To me this suggests overdoing the voltage/amperage if necessary so there will be no question that every rodent that completes the circuit will die immediately. I understand that a circuit like this could kill a human, so I will put it inside a housing that requires unscrewing and disassembly -- just like old analog TV's, microwave ovens, etc. have their dangerous parts safely protected from curious fingers by being completely enclosed.

I'm not an electronic circuit designer, but I know how to work safely around high voltage sources. I've worked as a residential electrician for years, and many years earlier my Dad (a TV repairman in the 50's and 60's) taught me how to safely extract vacuum tubes, capacitors, coils, transformers, and other electronic goodies from the old CRT TV sets he invariably ended up with through his work.

I'm looking for "industrial" quality here, meaning relative simplicity combined with exceptional reliability. Could an effective (yet minimal) circuit for this project be as simple as feeding the 110vac line voltage to a bridge rectifier, then to a large capacitor, then to the contacts where the rats will complete the circuit?

Even if such a simple circuit would work, I'm seeking suggestions that might make it safer, more reliable, and/or more effective. The housing will be weatherproof, but more than likely it will sit inside our barn for the rest of its life, so weather won't be a factor -- but temperature and humidity will definitely change, sometimes frequently.

 

 

Direct to line electrocution is dangerous and won't fly here. The staff is discussing some options including some from other members that may work for you. Meanwhile, take a look at some of these non-electric solutions from Shawn Woods. He is pretty good.

Bucket trap with roller.
Many more from Moustrap Monday.

Welcome to AAC and good luck!

 

OK, here is a solution that does use some electrical power BUT has no shock hazard if constructed in a reasonable manner. The best features are that it is self emptying and self purging, meaning that the marking scent rats try to leave to warn others will not be left in the trap. Once set up the system should be able to kill a rat every minute, or as fast as they crawl in to get to the bait.
I call the system a "Ratapalt" because it sends the rat flying out backwards across a shrp blade and into a 55 gallon drum for disposal, or it can send them across a river.
The device consists of a plastic tube, 2 inch ID plastic water pipe, open on the entrance end, with a few feet to a "Tee" fitting, and then a connection to a high flow air valve. At the side of the T fitting is a screen grate to retain the bait, along with a small light to illuminate the tube, so that the rat will feel comfortable following the tube towards the bait. There is a very small air feed to the bait compartment so that the smell drifts out the end of the tube, attracting the rats. Te end of the bait compartment is closed off with a screw on cap able to withstand the air pressure when the trapis triggered. Just before the rat reaches the bait compartment it breaks a light beam, which starts an electric time relay that immediately closes and stays closed for a short set time. When the relay closes it operates a normally closed air valve to release high pressure air, from a closely connected tank, into the tube. The several second application of high pressure air propels the rat backward out the tube at a high speed, which is determined by both the air pressure and the tube length. With a ten foot tube and an adequate sized air tank at 100PSI the rat comes out, rear end first, at about 75MPH, and hits a knife-edged blade a few feet away, and drops into the drum. The timer is set to switch off as soon as the rat is blasted out of the tube, usually about 2 seconds.As the tank regains pressure the system is ready for the next rat.
The benefit of this system is that there is no high voltage to pose a shock hazard or start electrical fires, nor any accumulation of dead rats near the trap requiring frequent removal by a human. The blast of compressed air will not injure a human, either.

I originally designed the system to deal with a severe rat problem that was damaging grain shipments to a port in another country that was suffering a food shortage. So folks are free to use this design to kill rats in any part of the world.

 

I think it's a bad strategy for rat control on a farm. A rat has to come for the killing.

You want to actively seek and destroy rat nests and young. Purchase rat terrier. It will clear much more than barn.

Edit: ....I would think the terrier would be good for snakes too......but if you have rats......you probably don't have snakes.

 

Get some cats, they're less maintenance than a dog. We didn't have a rat problem in our barn until our outdoor cat got old.

 

This device was intended for use in a warehouse in a port, not on a farm. While it could certainly be effective any place that there are a lot of rats, it was never intended to be an exterminator, but rather to kill the attacking masses. With an adequate supply of compressed air it can dispatch the nasty rats as fast as they enter. The original version shot them onto a spiked wheel, which would then turn because of the weight, and drop them into a barrel. That warehouse had a large population prior to this machine being put to use. The dead rats were used for fertilizer in a farm .In that instance it would have take an army of cats, which could have become a problem later on.

 

Living in the country we have rats living in close proximety, but, due to the type of use of neighbouring land, are not able to eradicate the rats even if we wish. In practice it has not really been much of an issue, at least as yet (over a period of many years). The best way we have found is to live in harmony with them. Avoiding providing a ready source of food, and having a tidy yard with no waste lying about sorts a lot. The only real increase seen was because of our neighbour putting food out for the birds daily. In short, the best thing to do is to think in terms of what would be a good environment for rats to flourish, then change this as far as possible to the opposite.

As regards lethal traps for the rats, at least in the UK, man traps are illegal so I suspect anything capable of seriously harming someone would be heavily frowned upon at the very least. The legal things are standard trips and rat poison (carefully placed where children, pets etc are unlikely to come across).



Tracy

 

Living in the country we have rats living in close proximety, but, due to the type of use of neighbouring land, are not able to eradicate the rats even if we wish. In practice it has not really been much of an issue, at least as yet (over a period of many years). The best way we have found is to live in harmony with them. Avoiding providing a ready source of food, and having a tidy yard with no waste lying about sorts a lot. The only real increase seen was because of our neighbour putting food out for the birds daily. In short, the best thing to do is to think in terms of what would be a good environment for rats to flourish, then change this as far as possible to the opposite.

As regards lethal traps for the rats, at least in the UK, man traps are illegal so I suspect anything capable of seriously harming someone would be heavily frowned upon at the very least. The legal things are standard trips and rat poison (carefully placed where children, pets etc are unlikely to come across).



Tracy

The system that I described is person-proof and fool resistant. And it would not injure any pet that was too large to climb into the barrel. In addition, it could be used in a non-lethal manner to simply send the rats away, if it were not aimed at a killing device. Sending a rat on a fast exit trip may even teach them to avoid an area.