Stuff you'll need:
- Small piece of cardboard
- LED (lowest voltage LED you can find)
- Thick copper cable. About 2 foot long
- Block of wood 15cm by 5cm by any thickness
- Galvanized nails about 1.5" - 2" long (MUST be zinc galvanized)
- Small panel pins/nails
- Drawing pin (could use nails if not available)
- Sheet of Paper
- Small pieces of wire
- Steel wire wool
- 2 litre plastic drinks bottle, or thin plastic
This instructable shows how to build a 5 cell version. I later built an 11 cell version in the hope of getting more light, but it's actually worse!. I guess the internal resistance of lemons is just too high.
Step 1: Strip the Copper Wire
Step 2: Form Coils for the Plates
You need to make 5 coils, and when you've done that you can attach the end of the wire to the nails, wrap around 3 turns around the nail. You want the nails to sit around 3mm away from the copper coil when they are finished.
Step 3: Nail in the "plates"
Remove all of the nails that you twisted the copper wire around in step 2. You can now nail all of the copper springs in place. They are all nailed in line with each other about 5mm between the nails and the next copper spiral. As you nail each on down, cut the heads off the nails.
Step 4: Attach a Wire
Step 5: Make a Switch
With the stop points complete, you can attached the other end of the wire that you connected in step 4. Then, push a drawing pin through the pivot point to allow it to pivot. To compete the switch, an elastic band is tied from the switch to the first nails that you nailed into the board. This returns the switch to the off position when not in use.
Step 6: A Reflector
Then cut a straight line to the centre, and a cut a small 1cm circle out of the centre. You can roll it around now, like one of those protective collars vets give to animals to stop them injuring themselves even more. Tape the cone together at desired shape.
The reflector is attached to the wood using a small piece of cardboard that has and angle cut at the same angle as the reflector. This is taped to the reflector and to the wood.
Step 7: Plastic Insulators
Step 8: Test an Led
Cut two pieces of wire about two inches long, strip the ends and attach a piece to each of the LED legs. Touch one of the wires the copper coil nearest the reflector, and touch the other wire to the copper on the switch. Does it light up ? If not try it the other way. If it still doesn't light up, there's either something wrong with your wiring, the lemons aren't juicy enough, or the LED is too high a voltage. The led I used lit up dimply at around 1.8V
If it's working, you can twist the wires around the last copper coil, and the straight nail stop on the switch.
Step 9: If It's Working!...
And remember, world domination of the lemon torch (flashlight if you're American) could happen at an moment! Be prepared.
Don't forget, you can use the sliced lemon in your favourite dishes even after you've run them flat....