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Totaly new to this stuff, need some help please please please.

L

Lascannon

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Ok, my name is Liam. I finaly managed to create a working laser driver. I have an lm317 chip, and instead of a pot and what not I put a 0.32 ohm resistor between the apropriate pins, and i have a capacitor to turn block "on spikes".

I originnaly built this for a red diode, which i pulled out of a DVD player. Unfortunately, I omited to use a housing, thinking that the heat sink already wrapped around it would do. So, I burned it out.

So now i am back, with a few more hours of research behind me.

What i am looking for is an extremely powerfull laser pointer. I do not want a toy. I do not want something I could buy in a dolar store. I am looking for an epic electronic project. It has so far been a legendary journey, wich i have enjoyed greatly. I am now ready to try again, now that i have a few more funds (I am sixteen, so if i want to try a project, I have to find a lawn to mow or something of the like.) I would like to order a powerfull green laser, and a laser housing.

To sum up:

What I have is this:
An LM317 chip
Several hundred assorted resistors
6 Lithium Ion Rechargable 3.7V AA batterys

What I need(or so i beleive):
Laser housing
Green laser diode
Resistence to use with the LM317 chip.

Can someone please help? I dont know how to calculate the mAh required for a diode, I dont know how to find a housing that will fit the diode, I dont know where to buy the parts so i dont get ripped off. If someone could please help me...

On a side note, I do nto wish to have an endless stream of drivers suggested using potentiometers. I believe that one of you can give me the correct resistence to add to the LM317 chip. That and a few links to reputable sites is all that I require.

If you have read this, thank your for taking the time to read it. If you can help, thank you again.

Now lets make some lasers!
 





Hello Liam,

Well first of all, your red diode died because you shot too much current into it.
You have put little over 0.3 ohms of resistance between ADJ and OUT pins of LM317, which equals to around 4 amps of current.

Now, to have your diode properly regulated, you just need to replace that resistor, with 3.3 ohm one, and your red diode (new ones, you've burned the last one) will work happily.

Now also, sorry to crush your dreams but you cannot "build" a green laser from scratch.

Closest you can get is to buy a complete laser module (which is diode, crystals, optics, and driver electronics in one) and install it into your own laser host.

If you happen to have any questions, you can PM me no problems asking about them.
 
Thank you so much for the early reply! I made a few changes (it is now 3.3 ohms, since i only had a 2.2 and a 1 ohm. Now i need a housing and a new diode. Can anyone give me a link? I pulled the originals out of a dvd player, but now I need new ones, I may as well buy them. presumably that is cheaper(cheeper?) then buying a dvd player and tearing them out.

Thanks so much,
Liam.
 
Howdy and welcome to the forum :wave:
You are off to a good start sounds like you
have allready gotten the good info so I will
just say Have fun and be Safe ;)
 
Just so you know, a good way to calculate the current your LM317 driver will output is this:

I = 1.25/R, where:
I is the current in Amps.
R is the resistance in Ohms.

And, generally speaking, for a 20x LOC red diode (the most common red diode), it's safe to run at 400-420mA.

For Blu-ray (which is close to ultra-violet, a really cool color), the cheapest diode is a PHR, which is safe to run at around 100-120mA.

For a royal blue, which is 445nm, they can be driven anywhere upwards of 1.9A. However, 1.5A is probably the safest.

Finally, there are green modules, but these generally always have drivers already built in.
 
Thank you Wolfman, for some reason I forgot to write that. + reputation from me.
 
Wow. This forum is fantastic. Thank you all for welcoming me and helping out. Its very encouraging when you ask a question and soemone answers within 10 minutes :D Ok, so Im ordering one of the axiz housings, and before i order any more diodes, I might have a a few more, if i can convince them to come out of their heat sinks. http://kng.puh.org/laser/ld1/IMG_4570.jpg If you look at this photo, the one on the left, I have to more of, and the one on the right, ive killed two of. Hope that makes sense. Anyone ever tried to take on of the larger ones out of the heat sink it comes with?
 
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I used a pair of side cutters and nipped away at mine until it came out. Just take it in small bits and don't hit the diode itself. The metal is relatively soft, it took me about 10 minutes or so.
 
Another good method is with two pliers.

Grab opposite sides of heatsink (careful not to go near diode pins or diode itself), and then twist in opposite directions.
Most heatsinks made for diode sleds are very brittle material and will snap easily.

Don't do it in one move, "work" it a littl,e back and fourth, and metal fatigue will kick in and it'll snap.

Be very careful not to harm your diode, or not to have it flying away when you finally snap the heatsink.
 
Yeah, this is the method I was going to try but looking at mine when I got it removed didn't look very feasible, or controllable. With the side cutters I was able to get a bight, then cup my other hand around it to catch metal bits and the diode should it have fallen out.
Plus my pliers are mini, no where near big enough to have twisted the metal lol.
 
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I just started the process, its very bent and I can see half of the diode. I am slowly cutting away at it, and some time soon I hope to have a diode. I might put it ( lightly and with some padding) into a vice and take a file to it.

other then that... am i all set? I think I might be. I just need to wire it all together into a nice casing (I have an ancient lighter thats big enough) and then Im done... I THINK.
Please correct me if im wrong.
 
What I sometimes do is stick one end in my vice and just squeeze it tight. Generally, if I get it positioned just right, it will split the metal opposite of where the vice is holding it. It's quite and, as far as I know, it's safe (haven't damaged any diodes this way).
 
Thanks. I will use all of these. techniques later today (Im at college right now).

On a side note, is there a way to move a thread? This just went from Green Laser, to Red Laser, to Laser Diode Harvesting.
 
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