Here's how to mash-up a digital camera rechargeable battery with LED safety glasses.

Background:
Awhile back, I bought a pair of those clip on LED lights that attach to the arms of glasses. At first, they worked great. But after a few hours of use, the button batteries slowly died to a point that they became useless. Continually replacing button batteries, (mine had three per each light) wasn't very economical.

I had an old Canon S100 digital camera in my junk pile, (the LCD was broken). I also kept the battery charger and two Li-ion 3.6V batteries. I figured I could use the Li-ion batteries to power the LEDs.

Tools:
Hot glue gun
Scissors
Wire cutters
Soldering iron
Saw
File
Pliers
Tin snips
Hand punch
Dremel

Parts:
Safety glasses
Clip-on LED lights - Electronic Goldmine - G16248 - $2.95
http://www.goldmine-elec-products.com/prodinfo.asp?number=G16248
Tic Tac container
26awg wire
Rechargeable battery
Battery charger
Double sided tape
Brass sheet
3/8" dowel
1/8" foam rubber
Can of Brain Toniq

Step 1: Make Battery Plug (optional)

Make a "plug" that fits inside the LED light's battery compartment. The plug provides electrical connection to the contacts inside the battery compartment. Using a plug gives you the option of reverting back to the button batteries if you change your mind. For a more permanent configuration, this step can be skipped by soldering the lead wires directly to the battery contact tabs inside the lights.

Punch (using a hand punch) or cut (using tin sips) some round contact plates from the thin brass sheet. The contact plates need to be about the same diameter of the button batteries. Two contact plates are needed for each plug - positive and negative. Make sure to sand off the finish from the brass plate first.

Next, cut off about 3/8 inch length of 3/8 inch dia. dowel. Cut two pieces, one for each light. File a shallow notch on the top and bottom of the dowel plug. This allows room for the lead wires.

Using 26awg stranded wire, cut off two sets of leads, one for the left light and one for the right. The left leads should be about 15 inches long, the right about 6 inches long. Strip then solder these leads to the contact plates.

Hot glue a pair of positive and negative contact plates to ends of the dowels. Twist the leads together and heat shrink the plug for a neater appearance.

Using a Dremel, make a small notch in the light's battery compartment door. This allows access for the wire leads from the plug.

Step 2: Make Battery Box

The essence of this entire Instructable can be distilled into fabricating a battery box.

It just so happens, the Canon S100 Li-ion battery fits nearly perfectly into a Tic Tac (breath mint sold in US) container. Modifications are simple.

The Tic Tac container is a little longer than the battery so shims are needed. Just cut two pieces from 1/8 inch foam rubber and use double sided tape and glue to secure the shims to the bottom of the container.

Next, make two copper contacts. From thin brass sheet cut out two strips as shown. Remember to sand off the surface of the brass, they usually are clear coated. Fold the contacts as shown. Solder the positive leads from the battery plugs to one contact and the other negative leads to the other contact.

Lastly, fix the contacts to the inside of the Tic Tac lid. Insert the Li-ion battery into the lid of the Tic Tac container. On the edge of the lid, mark the position of the positive and negative terminals of the Li-ion battery. The markings makes it easier to position the contacts. Then carefully align and hot glue the newly fabricated brass contacts to the inside of the lid.

Step 3: Final Assembly

The last step is to glue everything together.

Cut a notch in the Tic Tac lid door to give access to all the wire leads.

Hot glue the battery box onto the arm of the safety glasses. Hot glue the base of the LED light to the battery box.

Tape the wire leads to the glasses, routing them such that they do not bind when adjusting the LED lights or when folding the glasses closed. Remember to provide plenty of slack in the wires so that the Li-ion battery can be removed. Hot glue several spots to hold down the wires to the glasses frame.

Congratulations you are done!

Closing thoughts:
- The Li-ion battery puts out enough juice to run the LEDs for many, many hours.
- Instead of buying the LED clip-on lights, discrete LEDs and resistors would also do the job. But an adjustable LED arm would need to be fabricated. LEDs have a narrow beam so adjustability is important.
- Keen observers will notice the glasses used in this build aren't really safety glasses. : )