DIY Homemade laser diode driver

Awesome post.

ericsjobs said:

Awesome post.

Click to expand...

This, however, was not an awesome reply.

Bionic-Badger said:

This, however, was not an awesome reply.

Click to expand...

Ha ha ha, golden
+1

So if this driver circuit is for a dvd burner laser, then what are the values for a 445nm?

Don't use the CS5207-1 as alternative to LM317. It is highly unstable when used in constant-current mode against something with a diode-characteristics.
It will oscillate and over-swing badly.

Just wanted to warm people so they don't burn their ld's.

excelent tutorial, I will try it

just like to ask 2 questions about this circuit...


http://laserpointerforums.com/attac...laser-diode-driver-lm317_components01_001.jpg

1) why using 2 resistors ? isnt the potentiometer enaught? can I use just potentiometer with higher resistance?

2) the diode 1N4001 ... is it just for "correct polarity check" (so if someone changes battery +/- nothing will happen)?

The two resistors can be omitted, but then you'd have the chance of burning out the pot as well as the laser diode if you make one turn too many. The two resistors make the adjustment less sensitive and limit the range. A single pot will also have to dissipate more power.

The diode prevents negative voltages across the laser diodes, the LM317 may blow up though, I'm not sure.

Hey, I do not mean to ask questions that were already answered but I want to make sure I got everything right:
So it is possible to build excactly this driver in a smaller scale with smd parts? because I couldn't find a potentiometer in small. Is it possible to use a set of switchable smd resistiors instead or are ther smarter ways or really small potientometers i just couldn't find?
You said the whole circuit doesnt get very hot. So I could put everything in a really small housing without overheating?

The rckstr driver is pretty much exactly what you're describing. It's very possible to build this circuit small enough to fit inside an aixiz module.

Thanks ElektroFreak, looks promising indeed.
but for my application I would probably need to assemble this on my own because I need to fit the parts in a reeeally thin tube (the circuitboard shown would still be too big) so I guess I got to connect all the parts with small pieces of wire and arrange them in the tube.

You can etch a board fairly easily or you can build it on protoboard, that way you've still got a circuit board for structural support. You'd just need to shop around for some thin board stock. These methods do require a small amount of extra effort, but the payoff is much better structural support for the circuit, which results in improved reliability.

I don't know if it's my english that starts lacking or missing knowledge but I don't excactly get what You mean. So if You don't mind would You try to explain it in a different way and more detailed?
Maybe I should also add a little detail on what I have in mind:
I'd like to stuck all the electronics inside something like a "hollow ring" so like a small tube that was bend to a ring like shape. so all the parts would probably have to be in line to fit inside. If there are any good techniques for connecting the smd parts this way I would be happy to hear about them.
I'll get a little more into detail:
I am currently using a red laser diode from a dissasembled 16x dvd burner. I am not too sure about the voltage and current but as far as I got this guide I can use the same parts with my diode and a 3v battery (I am planning to use a rechargeble small cell).
My next questions are: will I need anything else besides driver and energy source? how do I get the most power out of the diode and does it need any lenses? Can I use lenses from the burner?

I appreceate any hints

You're actually asking some questions that are best answered in other parts of the forum. I'd really have a good look in the "tutorials help and repairs" section and the "optics" section as there are stickies there that can help describe various build options and select lenses.

You can still build a tiny circuit board that will fit inside your small tube by using protoboard: http://www.amazon.com/Perforated-Bo...3?s=electronics&ie=UTF8&qid=1327515734&sr=1-3

You would just need to cut it to size and solder the circuit together on the surface of the board. You can also etch traces onto bare PCB stock: Amazon.com: Copper PC Board 6 x 9 Single Sided: Electronics

In either case you'd want the thinnest board you can find to help keep things tiny.

Can i connect 2 2ohm rezistors consistent? and what 2 ohm rezistors i will need to use?what power?

1/2 watt resistors work well in my experience. You can connect two resistors in parallel to lower the resistance and increase power handling.

Yeah I didn't really know were to start with my questions. I just wanted to see if THIS guide would fit with my project and if I have to modify it.