Putting a laser pointer into an AVON Frozen projector watch.
You can get the watch here: http://www.avon.ca/shop/en/avon-ca/frozen-projecti...
The laser I scavenged from a Khet game.
Step 1: Opening the Watch
There are six screws and a battery door that need to be removed in order to open the watch, they are very small (eye glasses sized) Phillips head screws.
Step 2: Installing the Laser
The projection focusing lens is slightly larger than the laser emitter, so it wont quite fit. I decided to build up several layers of tape to get a nice snug fit.
When removing the LED and soldering the laser to the battery connector, I accidentally melted one end off the battery compartment. This actually came in handy later on.
Step 3: Batteries
The watch uses four LR41 button cell batteries which provide 1.5 volts. This is too much for our laser, so after a little research, I found that size 13 hearing aid batteries have the same diameter but are nearly twice as long, providing the voltage we need, and extending the longevity.
Size 13 hearing aid batteries have orange tabs, and are also known as ZA13, PR48, and 7000ZD
As you can see, the new batteries aren't long enough to fill the battery compartment. This is where having previously damaged the battery compartment comes in handy. The spring end is now easy to remove, and there are small ridges inside the battery door which can hold the connecting plate closer to the other end, effectively shrinking the battery compartment, and making the two batteries fit fairly well.
Step 4: Putting It Back Together
The laser emitter fits inside the watch casing. I did however need to slightly enlarge one of the picture holding slots in the rotating bezel so it would fit a little better. After you put the bezel back in place, the watch face sits on top, and holds the other pieces in place.
Step 5: Give It Back to Your Daughter
This might be the hardest step. I know it was for me.
The completed watch is nearly indistinguishable from the original, but is a great laser pointer for playing with the cat, annoying her brother, or whatever.