Intro: Cheap Homemade LED Torch (full Build)
A cheap source of LEDs
A full torch / flashlight
Step 1: LEDs
I found a pack of six gas-lighters with built-in LED lights for a pound.
Dismantling these was fairly easy, as shown in the pictures, it's not too dissimilar to 'breaking'
If you've got LEDs already, skip this.
Step 2: LED Assembly
Wire all of the LEDs together.
I've pushed the +ve electrodes through a small piece of insulation, cut from some heavy mains cable, like an elastic band this holds the electrodes together.
Also looped around the electrodes is a bit of thick copper wire.
The (yellow) insulation holds the electrodes in place while solder is applied, joining them to the copper wire.
A quick bit of soldering and you're done.
Next wire all the -ve electrodes together (see pictures). I've used individual copper strands from mains-cable, soldered and twisted.
Take a strand of copper (extracted e.g. from some mains-cable), tin it, tin the LED electrode and solder.
When you've done all six, twist them together, around the the outside of the central electrodes, to form a single -ve
Spend a bit of time getting the LEDs correctly aligned here. You can tweak and nudge the LEDs so that they form a nice alignment pointing in the same direction, but it takes a bit of time. Once you've got this to your satisfaction, it's time to move on to the next step
Step 3: Casting the Head
I'm encasing the unit in resin, using a handy mould I found.
Holes were drilled for the electrical connections, and I tried to seal up with Blu-tack (worked OK, but did leak a bit).
Regular resin for glass-fibre was poured in, and left to set.
The mould was cut away, but I could probably have forced it out.
Last (on this step) I've soldered a switch onto one wire, and a battery-contact onto the other. Both of these came from another horribly-cheap LED torch, which never worked (freebie)
Please see pictures, they are annotated
Step 4: The Rest
Roll a tube from paper around some AA cells.
I've coated this with resin, but tape would be just fine.
For the other battery contact I've got some wire through a plastic disc, screwed it up a bit and added a big blob of solder (this worked very well). The other end of this wire is soldered onto the switch.
Finally the tube is glued into place with some epoxy.
Step 5: End
Cut two slots in the end of the tube to retain the battery with a clip. Form the clip from e.g. a paper-clip, or other piece of stiff-ish wire. This has to be in just the right place, so take your time in getting it right. I can't think of the name for this type of clip (sorry)
Wrap the wire around the shaft, and finish with Gaffer-tape. It's not pretty.
So I took the tape off and improved the look of this, see next step.
Either 2 or 3 AA cells, will power this, slid down the tube (obviously). When using 2 I've had to improvise a dummy cell with card and foil.
Step 6: Finished Torch
Gaffer tape removed.
Most of the insulation was removed from the wire and the strands re-wrapped.
A bit more resin was added to the rear-end, with the clip-slots filled (temporarily) with card wrapped in PTFE tape. The open end was blocked with a piece of Blu-tac, wrapped in it's own waxy paper. The switch was masked with Blu-tac, and the LEDs masked with Blu-tac wrapped in plastic-bag
Sprayed with metallic paint, this looks much better