An Electric Fence for Snails and Slugs

Anyone with a garden knows about doing battle with pests. Weeds, bugs, rabbits, birds — all of them try to get a bite out of our flowers and vegetables. Some of the worst are mollusks. Snails and slugs are notorious plant attackers. Tomato plants don’t stand a chance when these beasts come to town. Some folks would reach for the pesticide or even the salt, but [wheldot] had a better idea. He built an electric fence to keep these pests at bay.

Much like the electric fences used for large mammals like horses or cows, this fence is designed to deter, but not kill slugs and snails. The design is incredibly simple – two bare wires are strung around the raised garden about one centimeter apart. The wires are connected to a nine-volt battery. No boost circuit, no transistors, just nine volts across two wires. That’s all it takes to turn a slug away.

[Wheldot] didn’t come up with this hack — it’s been around in various forms for years. The nine-volt battery provides just enough current to annoy the slug or snail. The best part is that when not actively shocking a slug, the only current passing through the circuit is the whatever is passed through the wood.

Reddit user [gnichol1986] measured that at around 180 kΩ through wet wood. That means a typical 400 mAh battery would last around 34 days of continuous rain. Even in the UK it doesn’t rain that much. With a little work insulating the wires from the wood, that could be extended to the full shelf life of the battery.

You know, slugs and critters get into electronics too, so don’t forget a waterproof case to make sure your project stays slug free!

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Are you smarter than a raccoon?

[Ben] has a raccoon problem. It seems that it’s not uncommon for him to come face-to-face with a pesky raccoon in the middle of the night, in his living room. We think most people would solve the problem by preventing the raccoon from entering the home. But [Ben] just seems hell-bent on catching him. Most recently he’s added motion-sensing to a live trap which he installed…. in his living room.

So [Ben] has cat’s which that to roam at night. They have free range thanks to a cat door which the hungry pest has been exploiting. Apparently the masked robber has a taste for cat food and that’s what keeps him coming back. [Ben] has been using the cat dish as bait but up to this point the live trap hasn’t worked. You see the raccoon isn’t going inside to get the food, but reaches through the cage and pulls pieces out one at a time. The solution is to put up a solid surface around the cage, and hope that the motion sensor will get him this time. Although we’ve linked the most recent post above, you’ll want to page through his blog for the whole story.

Wouldn’t it be better to install some kind of automatic lock that only lets in the kitty?

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Carnivorous robots

flypaperup

Artists [James Auger] and [Jimmy Loizeau] have put out this display of carnivorous robots. Pictured above is a clock that is powered by a microbial fuel cell. The clock is equipped with a scroll of sticky paper for catching the flies which it then scrapes into it’s cell for digestion. The other pieces include a mouse eating coffee table, a strange mechanism for stealing spider’s meals, and a lamp shade inspired by pitcher plants.