We took our instructable http://www.instructables.com/id/Film-Canister-Flashlight/ and modified it a bit.
Skip to step 7 to see the changes. Don't forget to check out the supply list though.
Step 1: Materials
3V Coin Battery
Film Canister With Lid (closes inside)
-Sold on e-bay or at catsscienceclub.com
Step 2: Magnet
Step 3: Battery Holder Option 1
Place the wire on to 3 volt coin battery. Using the electrical tape, tape the wires on to opposite ends of the battery. Make a note of which wire is on the negative end and which wire is on the positive end. In our pictures we have black as negative and gray as positive.
To see another way to build a battery holder that is a bit more challenging, but a lot cooler, check out our other instructable http://www.instructables.com/id/Film-Canister-Flashlight/
Step 4: Cut and Splice
Splice the wires connected to the battery at both ends of the extra black (negative) wire.
*Cooler battery holder shown in pictures. You can build yours at http://www.instructables.com/id/Film-Canister-Flashlight/.
Step 5: Prepare Toggle Switch
Take the extra negative wire (our black wire) and connect that to the center prong on the switch. Solder it on.
Now your switch is ready!
Step 6: Connecting the LED
Take the negative wire (black) that is connected to the toggle switch and wrap it around the negative leg of the LED. Solder in place.
Take the positive wire (grey) that is connected to the "battery holder" and wrap that around the positive end of the LED. Solder.
Does the light turn on? No? Try the switch ;-)
Step 7: Prepare Canister and Lid
NOW THE NEW STUFF :-)
Sand the top and bottom of the lid to make it more translucent.
Place LED holder into fender washer and glue in place.
Push LED through holder.
Take hot glue gun and cover the fender washer and the top of the LED that is sticking out of the holder. This will diffuse the light to give it a nice effect.
Quickly place the washer LED into canister lid as shown. Center the light into the lid
Step 8: Put It All Togeter
Hot glue the exposed wires but do not glue to the side of the canister or you may not be able to close the lid.
Snap on lid after glue dries.