Cheap Laser Pointers


I picked up some of these cheap laser pointer in Shenzhen, then proceeded to order a bunch more on eBay, they’re about 5USD each shipped. The purple laser shown above had no mW rating. But they generally claim to be 1 or 5mW. I hooked a purple laser up to a PSU and it drew about 170mA, 500mW. I’d guess these lasers are actually much more powerful than 5mW, they certainly look it.

By adjusting the collimating lens so it would focus on a smaller spot, the laser would even burn through plastic:


So I’d guess a few hundred mW. It’s not really possible to non-destructively disassembly the pointer, but I sacrificed one. Here’s the PCB.


I can’t find a good dataset for the 5152M, but it appears to be a boost converter. The voltage at the diode is around 7V, but I’d expect the laser to be driven in constant current mode, and I guess the boost maybe operating in this configuration.