You will need:
3v button cell battery (20mm)
Super-bright LED (your choice of colour)
Neoprene sheet. (or an old Mouse-mat , "Wonderfoam", foam tape)
Thin but stiff plastic (Yogurt container, Ice cream lid etc)
Double sided tape
Disk-sander (optional) Or make one!
NOTE: This Instructable has been designed to be used but children so please keep comments responsible. Thanks!
Step 1: The Sandwich
Roughly cut the center piece of neoprene into the desired shape and mark-out where the button cell battery might fit by tracing it.
Allow at least 5mm from your mark to the edge.
Cut out the hole with the utility knife.
If anything, it should be a little small and a snug fit.
Step 2: The "Bread"
Alternativaly, thin, stiff pieces of plastic could also be used as the outside layers and therefor there would only be 3 layers in total.
Step 3: The LED
I this case, I made a little notch for the LED to slip into so it would not protrude out from the 'sandwich'
If you do this, then the hard, thin plastic needs to be trimmed.
But not the outside layers!
Step 4: Assemble the Torch
The straight leg of the LED is next to the hard plastic and the bent leg acts a press switch on the top.
Step 5: Finishing
In these photos you can see one example with the LED not having a little recess cut in order to protect it.
Both still work really well!
If you do not have a disk sander the I really love THIS Instructable by M.H.Kabi. Could be great little sander and I will be making one myself to find out!