Simple Halloween 'Watching Eyes' With LEDs

We're having a Halloween party around my place, which is mostly taking place outdoors.  I thought it would be cool to have some glowing LED 'eyes' watching from the bushes and trees around the party, so I did some googling and came across LED Throwies.  They're kind of cool, but I wanted to have two LEDs running off one battery, and have them sufficiently far apart that they looked like glowing eyes from a distance of a few metres.

So, I came up with these 'Toilet Roll Terrors', or Bog Roll Bogles, if you're from my part of the world.  Essentially, it's two LEDs forming a simple circuit centred on a 'coin slot' for the watch battery that powers the whole thing.  It's all put together with tape, garden wire and a toilet roll.

Read on to see how they're put together.

Step 1: You Will Need

To build a Toilet Roll Terror, you will need:

- One standard toilet roll inner tube
- a roll of black electrician's insulating tape
- One Lithium CR 2032 watch battery
- Two coloured LEDs (red or green works best)
- Two five inch lengths of garden wire, with the plastic casing stripped off
- A craft knife
- A pair of pliers with a wire stripper
- Scissors

You can do this without the craft knife and pliers, they just make it much easier to cut, bend and trim things as you go.

Step 2: Prep the Tube

First of all, take your tube and cut a half-inch slit across the body of the tube with your craft knife.  Do this very slowly and carefully so you don't go through the roll and cut yourself.

Once you've made the central cut, gently push the battery into the slot to make sure it fits.

Finally in this step, cut two quarter inch slits at either end of the tube, ready for the LEDs.

Step 3: Insert and Bend the LEDs

Next, slide the two LEDs into each of the LED slots.  Make sure that the longer leg of the LED is on the same side as you look through the tube.  In my pictures, the longer leg is on the left.

Bend the legs of the LEDs out and smooth them against the walls of the tube.

Step 4: Create First Contact

Next, we're going to create the first part of the simple circuit.  What you are doing here is turning one side of the battery slot into a contact that connects to one leg of each LED. 

First, slide one of your garden wire pieces into the battery slot, leaving about an inch sticking out. 

Bend the wire over so it lies flat, then tape it down. 

Step 5: Connect the LEDs by Folding the Wire

Pull the wire tight and bend it around the end of the toilet roll, making sure that it touches the leg of the LED.   Pinch the wire flat make sure it is tight in to the toilet roll.

Once folded along the outside length of the toilet roll, carefully bend the wire down into the other end and across the contact leg for the other LED.

Pinch all wires as flat as possible, then tape them in place.

Make sure that the wire going along the outside of the roll is completely covered in tape and won't touch the battery when it's in the slot.  Also make sure that your wire hasn't snapped or fatigued as you bend it - you ideally need quite malleable wire which can be folded and bent 180 degrees without snapping.

When taping the wire into place, make sure you press the tape hard against the wall of the tube to keep the wire tightly against the LED legs.

Step 6: Repeat Steps 4 and 5

Simply repeat the same steps as above, but for the other side of the battery slot.  It doesn't matter if the two wires in the slot are touching - the battery will separate them when it is pushed into the slot.

Step 7: Insert Battery, Test and Tweak

Grab your battery and carefully push it into the slot in the centre of the tube, using your finger behind it to control it and bend the wires back into place if they shift.  If the LEDs don't light up, try turning the battery around.

Once the battery is in place and the LEDs are lit, go over all the connections, pressing down hard on the tape and wires to make sure everything is firmly in place.  Finally, paint, spray or tape the whole thing black if you want to make them blend into the bushes better.

You should now have a simple pair of 'eyes' which you can slip over a tree branch or balance in a bush.  For the best effect I find having them slightly far back among the leaves makes them look more scary.  Try putting them in small groups and at different heights.  Have fun!