Electric Fence

[DavidWardlaw]

I would like to build an electric fence around my garden so that animals do not enter it and eat all my vegatables. It's a very small garden (10' x 15') and every year animals enter it, especially at night and eat around half the vegatables (can't blame them, they are tasty). I have some experience in electronics and I have lots of parts laying around (batteries, wire, inductors, etc.). Does anyone know how I should go about doing this?

[I_Forgot]

Do you want to fry them or just discourage them?

I_F

[DavidWardlaw]

No, I do not want to fry them because I wouldn't want to deal with their dead bodies, just enough shock to shake them up a bit and discourage them from entering.

[theAnonymous1]

If your DIY venture doesn't work out; I have a real electric fence box you can have.

I've had the thing for years and don't even remember where it came from. Pay for shipping and it's yours. I'll post a pic of it in a bit, my camera battery needs recharged.

EDIT: OK, here is a pic of it lighting up a neon tube so you can see that it works. Picture is blurry because it was hard to take the pic right as it lit up (intermittent output).

[Cal Weldon]

Do you have troubles with slugs or snails? I have a solution.

[john blackburn]

Whats the slugs and snails info? We are having a plague of the things in England, what plants haven't drowned are sorely nibbled.

[star882]

Originally posted by Cal Weldon
Do you have troubles with slugs or snails? I have a solution.

A normal fence zapper is way overkill for those. I remembered one time when I zapped a snail with a 9v battery.
I have also heard that just copper works since when it's in contact with the snail, it forms a battery that gives a small zap without an external power supply.

[es44]

Actually there are people having constructed electrical fences for snails. It seems they are using either 12v dc or 12v ac, supposed to be enough to fry them.
We are invaded in Denmark by some Sibirian snails, who eat our own natural snail. They are real cannibals, and a very big plague, as they also love our vegetables.

Sorry the links are for Danish sites, but maybe you can "read" the pictures.

Best regards Ebbe

http://www.kirstinsbregner.dk/regist...le/snegle.html
http://www.dbamott.dk/snegle/elektrisk_sneglehegn.htm

[Nutzy]

I once made an electric fence to keep the dogs out of the veggie garden. They were both very keen on tomatoes and strawberries!

I got a couple of high voltage - low value caps, a rectifier, a diac, a triac, a charge limiting resistor, and an old ignition coil.

As the rectifier is fed through the charge limiting resistor, the caps get charged up. As the voltage of the caps hits the break-over point of the diac (set up with resistors, or a POT) it triggers the triac on which discharges the caps through the ignition coil primary.

It produced a nasty sting that would make the dogs yelp when they got up enough nerve to touch the wire every few weeks, but not enough to cause my idiot friends much drama when they would hold onto the fence wire in their game of dare!

Caveat - This method is not entirely...errr, isolated from the mains!

[TwoSpoons]

I used to design these things for a company called Stafix, now owned by Tru-Test. The easiest thing would be to go to a farm store and buy a "Strip Grazer". This is a little unit usually used to power about 20-50 m of portable fence, and used by farmers for "break-feeding" or "strip-grazing" of livestock. They put out about 0.1 joules at around 7-8kV. They are safe, robust, and painful.

Should you really, really want to build your own, a 20uF charged to 100V (thats about 0.1 joule), dumped into the primary of a car ignition coil every 1.5 seconds with a thyristor should do the job. You will need anti parallel diodes across both thyristor and storage cap. I'll leave timing and charging up to you. Be sure to have lots of isolation (30kV is standard) if you power the thing from mains!
Don't go faster or more energy - 1: you don't need it, and 2: you'd be heading into dangerous territory

Me - I'd just go buy one, along with the plastic insulators you'll need for the fence.

(personal claim to fame: designing the worlds most powerful fence energiser with a whopping 38J output at 10kV. Nearly killed myself when I got across the internal storage caps (900V dc:120uF IIRC) Nasty.)