DIY laser project

I am new to this forum and was searching for similar threads so if I am posting a common question I apologize in advance.

I am looking for a good 50mw green laser , not pointer. One that will connect direct to 3 volts.

One question that I have,
I purchased a few 50mw green lasers off eBay from china , just the cylinder gold frame ones, and attached heat sinks to them. I connected them to 3v and worked great, but they have all burnt out or something (showing the red light from the inside) I looked in using my phones Camara to see that so I didn't look right at it.

One of the lasers , the negative wire fell off and I resoldered it and it wasn't working, only the red light. Another wasn't working right off the bat, and another burnt out within days.

Also the resister on it seemed to be getting extremely hot after only like 8 seconds of play. So hot I can't touch it.

Am I doing something wrong?
Or did I make the wrong decision purchasing these ?
Are they low quality?
Or do I need a special power supply to plug them in to?
(I was using a computer power supply's 3v lead for one of them and just a universal plug switched to 3v for the other 2)

I am sorry if these are ridiculous questions, I'm just stuck in a rut right now, I don't want to fork out more money till I know what I'm doing

Probably too many amps on that power supply and you LED the laser diode.

Whaa? Can't have too many amps on a power supply, it'll only draw what it needs. My guess is they were just crap low quality modules, possibly being overdriven to begin with to get the 50mW stated.

possibly crystal epoxy melted, thus no green lasing and only residual IR. Heatsinking green modules is a tricky business

Anybody recommend and good reliable 50mw ish lasers with a long duty cycle for the money? I was hoping to keep it close to $50, but I could be off with the price, last 50mw green I paid 19$ from china and it died fast

What are you intending on using it for? If it's constant duty, I'd recommend staying will away from the pointer modules and getting something like this: 30mW 532nm 12VAC DC Green Laser Diode Module Stage Show | eBay

Just search eBay for Green laser show module and you'll get heaps of hits. Can't say 100% that they won't fail, but generally they're much better than the pointer modules.

This is exactly what I was looking for thank you! And thank you to everyone else who responded to this thread!

Also I am building a laser show project. When I'm finished I'll post some pictures or something. Thanks again

Just to verify: did you put those green laser modules into heatsinks? With proper cooling they shouldn't die that quickly. Things' suggestion is probably the best though. You can also buy some good high powered lab lasers from Lasever, but that'll cost a few hundred dollars.

This all seems unusual for these modules. Double-check your power supply, I am a bit suspicious of it. Make sure you measure the voltage/current draw when the laser is connected and on which gives it a load. I had a power supply that had the voltage increase as the load increased. blew a few components

EDIT: So you were using a computer power supply and an AC adapter to drive them.
I learnt the hard way that ATX power supplies output 3.3v, not 3v. This is not just my reading, but is stated on the 'pinout'.
Also, AC adapters (transformers) usually output a bit more voltage than advertised (some of my 12V ones average at around 15-19V.
You can build a LM317 voltage regulation circuit easily and cheaply. Search around.
Hope this solves the problem.

Can't say 100% that they won't fail, but generally they're much better than the pointer modules.

Click to expand...

Good call. My experience with green modules in this price range (usually repairing projectors) is the laser driver and heat-sink really makes life easier if you want to drive from AC/DC. The drivers are usually pretty flexible and will work from 6-12volts, and with the diode being encased there's no brittle wires to break. I run pointer drop-ins with a 5v source just fine (switched of course), but you then need heat sinking for the whole lot and the driver needs to be kept cool. The module you linked won't need additional cooling. Hit it with a 6-12volt switched wall adapter and it goes.

The actual diodes themselves though....meh, pretty much the same baloney as pointer drop ins in terms of falsely stated mW ratings and other silliness. That's...why I also agree on getting a 30mW version because that's coincidentally what most advertised 80-100mW versions tend to be :yabbem: