Those LR44, A76, or 357 size batteries are more expensive than the laser pointer!! I needed a reasonable alternative. This one looks kinda rough but it does the job well and it is extremely cheap.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: How the Thing Works in the First Place...
basically, there is a spring at the end of the original laser pointer tube. it takes the little batteries with all metal cases. regular AA or AAA batteries have an insulator around them. the only way for the pointer to work is if the - side is connected to the spring and the + side is connected to the inside of the tube. this inhibits you from using batteries with an insulator for a casing. so basically I connected the - side of a AAA battery to the spring and I put aluminum foil around the + half of the battery and made the tin foil touch the inside of the tube of the laser pointer. I only had dead batteries so I had to use three AAA's and a AA to get any power out of it. But I wouldn't doubt that one fresh AAA battery would do just fine.
Step 2: What You Will Need.( or What I Used )
1. tin foil.
2. a laser pointer (redundant you say?)
3. one or more AAA batteries ( you must have at least one AAA battery. AA's don't usually fit into the original tube.)
start by taping the batteries together like this. if you are only using one battery then skip this step. the tape also prevents the batteries from short circuiting.
Step 3: Almost Done!
basically, all you gotta do now is surround the + side of the battery int tin foil and make sure the tin foil is touching the inside of the laser pointer tube and the + side of the battery but not the - side. now you have a complete circuit. push the batteries down on the spring until the laser works and tape the crap out of it so it stays working. got questions? leave a comment or private message me. this cost me about 6 bucks including the laser pointer.
Participated in the
SANYO eneloop Battery Powered Contest