When our lovely friends at Leicester Hackspace invited us to their Chibitronics build night, we knew that we wanted to think outside the box. Chibitronics are electronics component stickers that are very thin and self-adhesive, allowing you to build circuits on paper and surfaces that would not usually lend themselves to electronics. They don't require any soldering and are also a great way for total beginners (like yours truly) to learn about simple circuitry.
A chance remark that the copper tape looked a lot like slug tape gave us this entirely sane idea. Why not use chibitronics to protect our plants and create a garden light show as they did it?
Picture your beautiful garden on a warm summers' evening. As darkness falls you sit on the patio, enjoying a glass or two of wine as fairy lights twinkle all around you. Sounds awesome, right? And imagine how much better it would feel if you knew that every little twinkle was a signal that one of the slugs that have plagued your prize hostas was meeting an u̶n̶f̶o̶r̶t̶u̶n̶a̶t̶e̶ end. This was the inspiration behind slugitronics.
Copper tape is used as an environmentally friendly way to repel slugs from plant pots. The idea is that the slug gets a mild electric shock from the copper and decides that the plant in the pot isn't so tasty after all. We wondered if we could create a circuit that would light up when a slug tried to cross it and administer a slightly stronger electric shock than copper alone would.
Step 1: Planning the Circuit
We needed to create a circuit that would not be completed until the slug crossed it, but that would complete at any point around the planter that the slug decided to climb. The circuit needed to incorporate an LED and a battery, but nothing else, and it is really simple.
The circuit is formed by placing two copper bands around the side of the plant pot. The first circles the planter completely, the second is almost complete but has a small break in it. The break forms an ideal spot to to run copper tape from the lower band (ground) to the cell battery that will be concealed inside the planter. We left a gap between the other band and battery connection in which to place our LED. The circuit is decorative as well as functional, and looks more like a design feature than a practical one!
Originally we placed the LED sticker over the top of the copper tape, but we found that the connection wasn't good or reliable. Adding some extra copper tape over the top made the connection far better.
Step 2: The Finished Planter
We couldn't test our creation in the wild, as all the slugs have f̶l̶o̶w̶n̶ ̶s̶o̶u̶t̶h̶ ̶f̶o̶r̶ ̶t̶h̶e̶ ̶w̶i̶n̶t̶e̶r̶ died, or gone into hibernation, or whatever it is that slugs do when it's cold (settled down in bed with Netflix and a bottle of wine if they've got any sense). But we tested our circuit using various conductive things to show that it does work as expected. We were going to make a Sugru slug for the photographs, but we couldn't find where we'd put it, so we had to make do with what we had to hand (midget gem sweets).
As the slug climbs the plant pot, it encounters our copper tape. It might just decide not to bother crossing it - there must be tasty plants that are easier pickings elsewhere. If it decides to carry on, it crosses the two lines, completing the circuit, lighting the LED, and hopefully administering a big enough shock that it will become an ex-slug. We are quite excited to see if any of them become undead as a result, so that our garden becomes live-action Plants vs Zombies, minus the peashooters.
Step 3: Looking Forward
There are other places we could take slugitronics. We could expand the circuit to integrate it into a network, where an audible alarm lets you know when a slug has breached your defenses, and a light shows you on which planter. We could also incorporate a microcontroller that keeps a running total of how many slugs have been nuked so far. But for now we are eagerly awaiting the summer, where slugitronics can be fully tested and we can enjoy sitting on our patio with a bottle of wine and twinkling fairy lights ;)
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