hello, new user, little laser project

Hi, I have been doing some research into various lasers recently for a little project. I realised quite quickly I don't know enough about them yet. This seems the best place to ask a question, for somebody without a physics degree, although it seems plenty of people here probably have one!

I started looking in to lasers to create a simple 3d laser scanner, I'm a 3d artist by trade, I don't do a lot of programming and i am certainly not an engineer. I was going to use a piece of cool software cool david laser scanner that simply users a webcam and a line laser. Which is great as the only thing I needed was a focusable line laser.
At first i want to see just how cheap i can build this thing, before doing something more advanced.

However my first try at a super cheap set-up was less than successful. This might not be the best place to ask this question, but I was unsure as to where to post this.
The important thing for me is to get the thinnest possible line, red/green whatever and not to fry anyone's retinas, for as little cash as possible

I purchased from ebay a 5mw laser line module, intending to connect it to a 5v DC power adapter purchased from the same dealer who said it would be suitable. When it arrived I realised I had bought a >10mw module, As I was hoping to scan peoples faces (eyes closed) and not burn out retinas I didn't want to run it at 10mw so I thought running just 3v would be best, the instructions said it would take 3v to 6v to get >5mw - >10mw. As I am not used to doing wiring, using a couple of 1.5v AA batteries seemed the safest option. So I got a battery holder, a terminal switch (like you get on a lamp cord) and just connected red to red, black to black, using the screw clamps in the switch. It worked great, then the next day it started to dim, then started to flicker off, eventually it cut out, I tried changing the batteries when it dimmed, but it made no difference.
the laser only cost me £8 so its not a disaster if I destroyed it, but I have no idea what i did wrong so I don't want to make the same mistake again.

Any suggestions would be welcome, or if you think I should post this somewhere else let me know and I will shift this part of the post somewhere else.

:thanks:

Welcome to LPF , all the info need will be here...just have a nose around

mutatedSeaBass said:

I purchased from ebay a 5mw laser line module, intending to connect it to a 5v DC power adapter purchased from the same dealer who said it would be suitable. When it arrived I realised I had bought a >10mw module, As I was hoping to scan peoples faces (eyes closed) and not burn out retinas I didn't want to run it at 10mw so I thought running just 3v would be best, the instructions said it would take 3v to 6v to get >5mw - >10mw. As I am not used to doing wiring, using a couple of 1.5v AA batteries seemed the safest option. So I got a battery holder, a terminal switch (like you get on a lamp cord) and just connected red to red, black to black, using the screw clamps in the switch. It worked great, then the next day it started to dim, then started to flicker off, eventually it cut out, I tried changing the batteries when it dimmed, but it made no difference.
the laser only cost me £8 so its not a disaster if I destroyed it, but I have no idea what i did wrong so I don't want to make the same mistake again.

Any suggestions would be welcome, or if you think I should post this somewhere else let me know and I will shift this part of the post somewhere else.

:thanks:

Click to expand...

Was this a red laser module? If so, I assume it had no laser driver. You see, laser diodes are VERY sensitive to current spikes and ESD so if you want them to live you need a laser driver to regulate the current. My guess is you now have a LED instead of a laser.

Could you link the laser you purchased or confirm it was a red laser with no driver?

yep it was a red laser module,
Focusing Red Line Generator, Brass Case, >10mW - Detailed item view - OdicForce Lasers Online Shop

the seller said 'The module has a built in current limiter' but maybe I misinterpreted what that meant.

I had no idea a driver was needed, I thought that was just if I was putting it together from scratch with a diode etc. I didn't do much research before buying it at all...

having looked around the forum I have already found a few threads that explain things mostly, so putting together a new shopping list of components and tools needed. I need a driver, a soldering iron, a test load, a digital multi meter, and a new module. I don't fully understand this all yet, my electronics knowledge is pretty terrible but i will keep reading.

I'm beginning to think i may have been kidding myself if i wanted to build this laser much cheaper than anything off the shelf.

Yup, unfortunately, and unknowingly, you kip-kay'd it. That is you hooked the diode up straight to the power source. No biggie, welcome to the laser hobby!! We have all killed diodes and learned from our mistakes.

This can be an expensive hobby, especially to get started if you don't have the proper tools but can be rewarding.

A good place to get started are the two links in my sig.

Good luck, and if you have any other questions just ask!

Welcome to LPF. Most of Us have Killed a Diode along the way to enlightenment. Members here are glad to help out, so just do some reading then ask the questions to clarify things.

To totally contradict Kevlar, (no offense Kevlar ), I actually think there is a driver board there. It wouldn't run at all if you put 6V through a red diode. If it's a low dropout driver then 3V is enough but if it's not then it may just be falling out of regulation. From what you decribe however, it does sound like it died. You can try with 3AAs to see if that revives it but I doubt it. Just drop Jon a line and explain what happened. He's a decent chap. I've had quite a bit of stuff from there.

If you want to try again you can go for any of the cheap modules on this page -

Red and IR Laser Diodes and Modules - Items - OdicForce Lasers Online Shop

And get a couple of line generating optic here -

Line Generator Disc (2-pack) - Detailed item view - OdicForce Lasers Online Shop

The optics just mount directly to the front of the module. DO NOT USE SUPERGLUE! It'll cloud your optics.

Cheaper option than the one you initially bought. Did it say on it that it was >10mW? The specs say <10mW.

Good luck.

Morgan

This laser--- DealExtreme: $4.07 Red Laser Module - Focused Line (3.5V~4.5V 16mm 5mW) ---is a decent enough laser for your application. At $4.07US, you can buy a bunch and replace them if and when they burn out. I had one of these running off of a DC adapter(3V @ 300mA) for over six months before it "LEDed" on me. We call it LEDing when they stop lasing and only produce a small amout of light like an LED.

Sounds like a fun project. Good luck.

Steve

good news... in a way, Jon from odicforce sent me a message saying this laser should be able to take power directly, so like morgan suggested it probably does have a driver.
I did buy this one over the cheaper ones on the site because the black case looked like it may contain more than just the basic module, but i really wasn't sure.
He has suggested I give it another go with a different power source or send it back to him, so i will try out the 5v power brick i was originally going to use.

also I must admit i missread the ebay description, it was rated at >5mw on ebay and arrived saying >10mw so it was exactly what i ordered.

thanks for all your suggestions.

Welcome to l.p.f.!!!!!!

Hello,

Welcome to the forum & read as much as you can.