Beginner Help

first of all, Im bad at english and i´ve read the Laser help.

today i opened my old DVD Burner to get out The Laser Diode, its a Class 1 B3. i´ve heard from someone that B means its invisible, when i hook it up to a battery to test it, there is only coming red light to start it then it dissapear so its invisible (i think) i know nothing about what Power my laser has, but do got a picture of my Burner.

Burner: >> Picture <<
Diode(still housed): >> Picture <<

im planning to order this module cause i cant find Aixis module on the internet Nearby >> Picture <<

also i would like to ask for what purpose you need a driver. the only thing i read about that on the laser help page, is how to make one yourself or where to buy.


Hope someone can help me out.

GiantJordi said:

first of all, Im bad at english and i´ve read the Laser help.

today i opened my old DVD Burner to get out The Laser Diode, its a Class 1 B3. i´ve heard from someone that B means its invisible, when i hook it up to a battery to test it, there is only coming red light to start it then it dissapear so its invisible (i think) i know nothing about what Power my laser has, but do got a picture of my Burner.

Burner: >> Picture <<
Diode(still housed): >> Picture <<

im planning to order this module cause i cant find Aixis module on the internet Nearby >> Picture <<

also i would like to ask for what purpose you need a driver. the only thing i read about that on the laser help page, is how to make one yourself or where to buy.


Hope someone can help me out.

Click to expand...

Uh Oh :\... if there was light to begin with and it stopped... that means you killed your diode. NEVER connect a diode to a power supply without using a current regulating driver.

You need a driver because a battery has too much power in it for most lasers. And even if you're lucky enough to have one survive on a "direct-drive", they heat up in use which makes them draw more current and eventually die. A laser driver will regulate the current to a safe pre-set amount and will keep the laser running at that current which (if you set it within the laser's safe amount) will keep it alive for use whenever

Yep, sounds like you fried your diode.

Direct-drive (which means not using a driver in between the laser and the battery) is NEVER a good idea.

Lasers require a Constant Current power source, which means it limits the current to the laser and voltage is allowed to float to whatever level it wants to (within limits). You can build a simple driver with a LM317T, 1 resistor, and 1 capacitor. It will require 3 volts more than whatever your diode's forward voltage (Vf) is, but for a first build you can't find anything easier. There are a lot of writeups on this forum about how to do it, just search LM317.

(and if you want the quick and dirty version...

For a red diode use a 6V lantern battery, positive of battery goes to the + side of a 47uF capacitor and to the IN PIN of the LM317. Negative of battery goes to the - side of the 47uF capacitor, and then to the - pin of the diode. Put the resistor between the ADJUST pin and the OUT pin of the LM317; use ( R = 1.25 / I ) to find the resistance of the resistor you need. I is in AMPS, so for example 100mA = 0.100 Amps. If you wanted to supply 100mA to your diode then R = 1.25 / 0.100 = 12.5 Ohms, use a resistor whos value is close to 12.5 ohms. Now connect the *ADJUST PIN* to your Diode's + pin. DONE.

I recommend you start with a larger value resistor (a smaller current) and work your way up to more current gradually. When your laser starts shining bright, you have enough current.
*A common mistake is to connect the diode's + pin to the OUT pin of the LM317, but the connection to the diode must be made AFTER the current limiting resistor. After the current limiting resistor is the ADJUST pin, so it is just convenient and simpler to say "connect the diode's + to the ADJUST", which rhymes anyway. XD)

Yeah, it looks like you killed it. You should start with a lower power diode if you're a beginer. You also need laser glasses (not sunglasses) for the right wavelength protection with a diode like that. Go on Life long experimenter - It can be done and read a bit on his site about drivers and laser saftey and it might make more sense

thanks for all the replies People. so ill need to have a driver for constant Voltage.
how about the Module i posted? is it a good one? it has focus changing.

It would be better to get one with no diode already in it. You can get them on the internet for about 4 bucks. This is a good diode 5.6mm 650nm 5mW red laser diode best price 4 Pin | eBay
Depite it's power, it is not a big loss if you kill it

GiantJordi said:

thanks for all the replies People. so ill need to have a driver for constant Voltage.
how about the Module i posted? is it a good one? it has focus changing.

Click to expand...

Constant CURRENT!

not constant voltage!

Constant CURRENT is what i mean :O bad english remember.

about the diode, i live in the netherlands. thats on the other side of the world since its shipping from hongkong.

He's a fast shipper, I am (almost) on the other side of the world of Hongkong but I get my diode within a week or two.

No problem, just wanted to make sure you got it right. It would be a shame if you were to fry your diode!

well all comments alrdy told i fried it xD

so these are the things i need?

Laser Diode
Laser Module
Driver LM317
Battery ???? (whats the minimal and maximal V the Laser can hold?)

thanks for all the other information

i still got a LG burner as a spare. when i ever finish it i will let you guys know xD

EDIT: The Diode is still working cause i checked it more then once

I meant if you fry the new, replacement diode.

for a simple driver:
LM317
47uF aluminum electrolytic capacitor
apropriate resistor (I cannot tell you what value you will need as I do not know the current your diode requires.)

You will also need:
a laser module
a lens for the module (not all modules have lenses included)
battery: (battery should be 3V HIGHER than the Vf of the diode, again, I don't know your diode so I can't provide an exact answer.)

So, you will need 2 pieces of information to make this work:
1) The Vf "Forward Voltage" of the diode.
2) the Threshold Current of the diode.

You make the driver provide at least the threshold current and connect a battery that supplies at least the forward voltage + 3V. So if your diode had a 2.75v Vf you would need a battery that can provide at least 5.75V. Try to not go over the Vf by much because any extra voltage becomes heat.

the way you tell it, its like its impossible for me to make

Not imposible, but you need some skills for making lasers. Read a bit, and it might all make sense. If you contine this hobby, you WILL make lasers someday, just like me

If I made it seem that way, I apologise.

You would need a basic grasp of electronics to make it work though. Without those two pieces of information you would just need soldering skills, and you could be told exactly what to get and what to do, and it would work, no problem. But without them, you have to try several things and figure out what will work, which takes a bit of understanding.

You can assume the Vf for a red laser will be between 2V and 4V, so if you supply 6V it should work (3V plus the 3V the LM317 takes away). As for the current, it is always better to start lower and work your way up, which means you would start with a higher resistance and work your way down. Try 68 Ohms and work your way down to 10 Ohms, once the diode lights up brightly you know to stop and use that resistor.

These days it is far easier and simpler for someone new to just buy a diode where they know exactly what Vf and what current to supply to the diode. That is the advantage of buying new instead of ripping a diode out of a piece of hardware that is old/used.

once again, thanks for all the information now that i know that someone believes i can do it i will try my best.
EDIT: i found a driver at internet. this Schematic will do?

>>> Picture <<<