Newbie question...

Hello, this is my first post and this forum is great! i´m pretty new to lasers and i would like to know something, i already broke 3 <5mw laser pointers just testing...

I connected the modules to a 3v 250 mA dc power supply, but they don´t seem to last too much, they get overheated.
So i was wondering what is the difference between a 20 U$S module and a 300U$S one, just the heat dissipator? i´m trying to build a system that could last about 8 hours a day, any recommendations will be greatly apprecited :thanks:

Welcome.

You don't give too much informations, but i can try to guess ..... as "<5mw", you mean the keychain ones ? ..... if yes, consider that, opposite to the first types, actual keychan ones does not have a driver, usually just a resistor for limit a bit the current, and that the current is basically limited from the low one available from the button batteries ..... so, if you hook them to a power supply that have a bigger current capability, they blow quickly.

Also, the so-called "universal" (i think in the USA they call them wallmart or something similar) power supplies, are all, except stabilized ..... a 3V output can easily go from 4 to 6 V .....

Your key chain models may last 8 hours a day only testing will tell. you are burning them out with your power supply you need to put a dropping resistor in one of the power leads to the laser. get 1 watt type resistors, try any thing close to 50ohm, 75ohm, 100ohm, get these and use the 100 first if you need it more bright then use the 75ohm, if it still isn't bright enough then put the 100 & 75 side by side and connect them this will give you aprox 66ohms and so on till you reach your brighteness, rember you shouldn't try to make it any brighter than it is with the battries or you will just burn it out quickly. if you need more brightness then you need something more like a labby type laser that has a hefty dode turned down so it can run for long periods of time. just my .02

Pyro...

Welcome to LPF. Enjoy your time with us here.

I would hesitate to run my lab laser modules 8 hours a day.

I have included a handy guide to assist you in finding what you need.

hey! thanks for the replies, this forum works fast!
Ï´m using a keychain laser, the cheap ones <5mW (class IIIa), as far as i know if i use more mW (class IIIb) it could be dangerous to the eye, even the reflections, the laser is intendend to be in a public space, pointing to a plastic surface, so this area is kind of crucial.

I´ll buy a stabilized power supply and the resistors, (the laser burns even with the batteries if is turned ON for many minutes) and keep testing, it will be ideal that i can build the laser myself, or a cooling system to support these keychain modules.

This forum seems to be a great resource of information, so i´m going to explore a bit more.

Thanks again to all! really apreciatted, if you have any more ideas or advices/experiences to share i´ll take them

Aixiz has a sweet little 15mw green lab laser in an aluminum block that runs on 5 volts, you could turn down the adjustments to a low setting and I doubt it would ever over heat.

Just say the word, and I'll get you the link. Oh and they only charge $40 for it.

Hi photonaholic, that laser from Aixiz seems great, but as i told it should be class IIIa, so i wont blind or disturb anyone with reflections near the laser. By turn down the adjustments you mean that i can make it a <5mw one? if so, how can i measure the mW on a laser, or does it have a potentiomenter/regulator? I´m very interested now on that laser, I just went to their website but i can´t find that model, if you have the link to send me... :bowdown:
Besides yesterday i spent some time navigating this forum and saw a lot of people that make custom lasers, can you recomend an expert builder not to expensive (i live in Argentina, and with the shipping and customs fee it´s certainly that the price will double or more)
Thank you again photonaholic!!, if i found a class IIIa green laser that don´t overheat i´ll buy it as soon as possible.

Niko lives in Argentina.

Here is a direct link to that laser, and yes you can turn it down to a safe level.

aixiz.com StoreFront

Unless you point this into someones eyes, it should be safe for a laser art display.

Wow, super fast reply photonaholic, thanks!
I´ll look up for niko, and i would like to make you another question, if you please me: I´ve heard about divergence, my idea is to use a beam splitter and mirrors (or it was before i found this forum and see that the lasers that don´t overheat costs about $300 in other laser companies), but the beam splitter/mirrors still as a good idea, specially for visual effects. But one the salesmen told to keep in mind the divergence of the beam, since the reflection in mirrors could make the beam diameter bigger and bigger, and i should buy a laser with a low divergence, any advice??
anyway, i´m going to buy that module at aixis in the next few days and start doing tests, A huge Thank you!!!

Manuel

PS: i also need to find laser googles, since on my experiments last year i was doing all my testing without them and pointed the laser in my eyes a couple of times without noticed it... :yabbem: ,
since you have that much experience perhaps you can reccomend me some at a good price?

But again the aixis page was a goldmine for me, yo saved my day ;-)

For normal work / play with green and violet lasers, cheap goggles from Focalprice are good ..... if yo plan in the future to work with high powers and lab sets, maybe it worth the expense of a professional goggles set, but for the start these ones are ok (ofcourse, they don't stop red/IR, for this you need green/blue ones)

For an art display, divergence will not be a huge factor, it takes a lot of distance before you notice a big increase of the beam diameter.

HIMNL9 already said where to get some eye protection.

Good luck with your project, and when you finish it, take some pictures and post them on the forum for us. (please)

Hi guys, thanks for your advices and help, when i have the images i´ll post it here, you were reallyyyy helpful. :wave: