Hey! My name is craig and i just signed up today. Ive used this forum for information for a long time now, so i figured instead of searching through old threads for answers i may or may not find, i should probably just ask my question.

So,
i am building a blu ray laser into a flashlight. for the driver, ill be using an lm317, a resistor of undetermined value, and a .1 uF capacitor.

This is the diode - New 100mW 405nm Blue-Violet blu-ray Laser Diode | eBay

im guessing its a 5.6mm? i hope so. im very low budget here, so buying anything in excess of 10-15$ isnt really going to work. So i was wondering

A: Is there a better, more reliable diode for the same price range?
B: What is the best module to put this diode in?
C: How should i set my driver?
D: What is the best voltage to run this diode at?

I would really appreciate any help i could get.
Thanks in advance!!

Craig

Scratch that, ill be using this diode... PHR-805T laser diode 405nm 100-120mW [M0025] - $9.99 : Modwerx Shop

I believe the ma to mw ratio is about 1:1, but there are some graphs around that have more accurate information. Aixiz module would be your best bet, phr 805t is 5.6mm. I believe these need 4.5v to run, but you could use a boost driver.

For that diode there should be a tutorial about how to build it and power it. I believe you can use a 9v volt battery(edit never mind don't try that) for it if you set the driver right , but don't take my word on it.

This is actually going to be my first laser that ill be constructing completely. im 17 and i major in electronics at my high school, so i have a decent idea of what to do, i just want to make sure i dont break my diode (cost -_-) and that i can get a good amount of use out of it. will i need a heatsink? its running at a medium wattage...

No, no Craig. LPF helps those that help themselves. That was pretty lazy of you there. If you've been using the forum for information for a, "long time now", you should know how we operate. In fact you should know the answer to most of your questions too.

Please try harder. All the answers are there and you only have to search...

Let's see if you can find routes to any of that information you're after in the link in my sig.

M

well morgan, i was just looking for a quick bit of PERSONALIZED advice. i get what you were saying though lol and i've been to your "i want to build a laser" (which i think is awesome btw, good job) do you think that it would be completely necessary to heatsink that diode?

If you are going to run it at +100mA for longer than a few seconds, you will absolutely need a heatsink.

A: Is there a better, more reliable diode for the same price range?
Nope....there are GGW and sf-aw210 diodes that are about double the output, but cost about double the price.
there are also 8x and 12x diodes that can reach >700mW, but they can run you around $50 a pop. Not something you want to risk if your inexperienced in building lasers.

B: What is the best module to put this diode in?
Aixiz. It's the "standard" for all our 5.6mm diodes.
Laser focusing module for 5.6mm laser diodes (adjustable focus) [M0022] - $3.99 : Modwerx Shop

C: How should i set my driver?
You use a test load to visually see what your driver is outputting using a voltage meter. You can also calculate it. (1.25 / ohms = current)
example: 1.25 / 33.3ohm = 0.03754, so it would add approximately 37mA
you can just combine different resistors to get the desired current.
This method allows you to use fixed resistors instead of pots and does not require the use of a test load and digital multi meter to set your driver's output current.

D: What is the best voltage to run this diode at?
If i recall correct, the dropout voltage of the lm317 is like 2.25V, and the input voltage for the PHR diode is 5v. So your going to need a minimum of 7.25V to even power it.
Most people use 2x 4.25v rechargeable lithium.

Hope that helps.

Also, those diodes are REALLY sensitive to ESD to make sure you use all precautions. At minimum use a grounded wrist strap. Use a test load (dummy load) to verify the current of your driver, you can build one very cheap.

See here: Laser driver - It can be done

The only answer you wouldn't have found is the one about similar diodes. Usually the diodes mentioned and sold here are the best value for the output so you're not likely to find mention of others. It's only price for that diode that you can look for.

The other answers you should be able to find.

I wasn't being tetchy. I've seen a lot of folks get answers really quickly to questions and are therefore actively encouraged not to bother looking for themselves. The best way to get answers from all reading your question posts is to link to places you've checked out that haven't answered your questions or at least show you've tried to look. Saying, "I can't be bothered to look so I'm just going to ask...", (or similar), will illicit little response from most.

M

i understand, and thanks all for the tips =D