Hacking a Green Laser Pointer

Hacking a Green Laser Pointer
(Last modified 4 Dec 09)

I picked up a couple of green laser pointers from a vendor on Amazon in late November, 2009; here is the link. I wanted these lasers to use in some light-show experiments, so actual optical output power wasn't crucial; I just wanted them way brighter than the 5 mW red laser I'm currently using.

The green laser pointers are sold as 50 mW and have a tag that says the optical output power is < 50 mW, but I have no way of knowing exactly what it is. But they are plenty bright enough for my uses, and at $19 each, I'm happy.

However, I wanted to change them a bit (naturally!). Rather than run from the normal two AAA batteries, I wanted to hook them to a regulated 3 - 3.3 VDC. Since I didn't need the batteries, I also wanted to get rid of the battery case and make the laser module as short as possible. The pictures below show what I did.

WARNING!
The following procedure is quite delicate! Use caution and
work carefully! If you rush this work or aren't careful,
you could easily destroy your laser pointer!

First off, above is a picture of the laser pointer as I received it. The laser pointer wants the batteries installed with the positive end to the right (opposite of what's shown here). This means that the metal barrel of the laser pointer is connected to the positive terminal of the battery. This is important, as you'll see later on. If your laser pointer uses the batteries in the reversed configuration (negative terminal to the barrel), you will need to change a step below.

Above is the laser pointer with the battery holder removed. I used a Dremel rotary tool with a cutting wheel to cut completely around the case. I cut through the case at the center of the small pushbutton switch; see below.

Above is the case with the battery holder removed; I've also unsoldered a small spring that was attached to the center tab on the PCB. You can see where I cut into the case right through the center of the switch. Note how close the tiny PCB is to the wall of the battery holder! There isn't much free space; if you run the cutting wheel in too deep, you will destroy the PCB!

Above is the final hookup, showing the power cables I added so I can apply 3 - 3.3VDC to turn on the laser. Note that the positive lead is wired to the PCB and to the case! If you don't make this connection, the laser won't light. I used a scalpel and small file to clean off the rubber covering of the laser barrel so I could solder directly to the barrel.

Note: I connected the positive lead to the barrel of the pointer because this laser pointer wants the positive terminal of the battery connected to the metal of the barrel. If your laser wants the negative terminal of the batteries hooked to the barrel, you will need to make a suitable change when you wire up your power leads.

As shown, the small switch is no longer functioning. If I apply voltage to the two wires, I get laser light.

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