Laser Pistol for Kiwi

My cat Kiwi absolutely loves chasing laser pointer beams.  The only problem is that the tiny little watch batteries in the pointers run down and dim after only a few minutes.  I decided to build a better pointer.

I started by taking apart the laser pointer, where I found that it was powered by three little watch cells with a nominal voltage of 4.5v.  After taking a quick look at the circuitry, it was pretty clear that the the diode was actually just a 5v part being under-driven slightly.  I the laser up to a 5v bench supply for a few hours to make sure that nothing overheated and it was fine.  To provide a nice stable 5v to the laser, I used a 9v battery connected to a 5 volt regulator in a TO220 package.

The larger battery required a larger case, so I chose the most natural format for a laser… a pistol!  I went to one of the local big chain discount stores expecting to find dozens of toy guns with convenient battery compartments to choose from.  Unfortunately, I was sadly disappointed… I guess gun toys are a lot less tolerated/popular/PC these days compared to when I was growing up.  Determined to not leave empty handed, I settled on an assortment of 5 water guns for $5.

Anyway, I cut up the water gun a bit, mounted a switch behind the water gun’s original trigger, and secured the laser at the tip.  The results are a laser pointer which will last virtually forever before having to change batteries mounted in a way cooler container!  And Kiwi thinks that it is just great.

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