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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[Lenore] Eviscerates Her Racing Snail

 

You may have walked past [Lenore’s] unassuming card table at Maker Faire this year. But we’re really glad we stopped for a little chat. She went so far as to pull the working parts out of her racing snail to show them to us!

Wait, wait… racing snail? Yeah, this is a pretty neat one from a few years ago. The snail is a relatively large version of a bristlebot (incidentally, we believe bristlebots were originated by EMSL). The thing that’s missing here are the bristles. Instead of using a scrub-brush for this large version, [Lenore] discovered that velvet has a somewhat uni-directional grain. But using a piece of mouse-pad cut to the same footprint as the velvet she was able to get the flat-footed snail to move in a forward direction purely through the jiggle of a vibrating motor.

If this sparked your interest there are tons of other bristlebot variations to be found around here. One of our favorites is still this abomination which shifts weight to add steering.