Following on from my first Instructable, I decided to make a battery powered LED car. The head & tail lights are so small that using plastic fire optics was the only way to go, also the small amount of space inside the car for holding batteries.
All this cost only three UK Pounds to make (and about ten hours!), plus some stuff from one of my many junk boxes*

*That's what my wife says are in the boxes, little does she know!

Step 1: Required Tools.

1. Soldering Iron.
2. Hot Glue Gun.
3. Rotary Drill (Dremmel).
4. Scalpel Set.
5. Pliers.
6. Wire Strippers.
7. Needle Files.
8. Drill Bits.
9. Helping Hands (Crocodile Clips on a stand, with magnifying glass).

Not all shown in this Picture.

Step 2: Required Materials.

1. Hotwheels, or any die cast car.
2. Red LED & White LED.
3. Plastic Fibre Optic cable. (mine was reclaimed off a UFO Lamp)
4. CR 2032 3v batteries, 2x. (Motherboard batteries).
5. Wire.
6. PVC Tape.
7. Small switch.
8. Blu or White Tak.

Not all shown in this Picture.

Step 3: Take the Car Apart.

Drill out the rivets under the car, start with a small drill bit the increase the size, I used four sizes.
You can throw await the interior section as the batteries will not fit in. I did try to nibble away this section but by the time the batteries did fit all I had left was the dashboard!

Step 4: Drill Out the Lights.

This step is far easier if you have a plastic grille & tail. using a very small drill bit, 1.5mm, hold the drill in a fixed position and then VERY SLOWLY bring the grille or tail towards the drill, and mind you fingers! Then repeat the process for the tail.

Step 5: Drill Out for the Switch.

Line up the switch and batteries on the base plate to find the best configuration, then drill & file the hole for the switch.

Step 6: Solder the LED's.

Solder the wires to the two LED's, no need for resistors with 3v batteries.

Step 7: Wrap the LED'S With PVC Tape.

Wrap the + first then the - and then wrap them both tightly together.

Step 8: Add the Fibre Optic Cable.

This step is very tricky, try to bend the cable into the holes for the lights, I found that wiggling the cable to create some heat whilst bending worked well, but be careful because this cable can break very easily. Leave some cable protruding out from the lights, this can be trimmed later.
When you have the adequate shape & sizes of cable wrap them into the LED's as tightly as you can, so no light escapes.

Step 9: Test the Lights.

Tape a battery to each of the light assemblies to test them, to make sure they are the right shape & length.

Step 10: Assemble the Lights & Switch in Place.

You can Hot Glue the switch in place, but DO NOT use Hot Glue on the lights, this will melt the Fibre Optic cable. To keep the light assemblies in place use the Blu Tak.

New switch added.

Wiring diagram.

Inst wiring.tif
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Step 11: Attach the Batteries.

I used PVC tape to attach the wires to the batteries, this is so the can be easily be replaced.

Then use the tak to hold all the wires in place & the Fibre Optic cable. for a more permanent fix you could use something like Milliput.

Place the batteries on top of the wires, then re-assemble, found that some Tak around the rivet stalks held on the body.