How to Build a Laser (general Guide)

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Introduction: How to Build a Laser (general Guide)


Step 1: What Do I Need to Build a Laser?


Basically, you need:
laser diode (LD)
collimation optics
current regulator (aka driver)
power supply
heatsink
something to house all the electronics (project box is ok for a first build)

then  you can add other optional things:
safety switch
LED for power indication
cooling fan
etc...

Step 2: What Tools Do I Need?

You need:
soldering iron
solder
DMM (digital multi meter, even the cheapest works fine)
some wires (the more flexible the better)
small pliers

other useful tools:
tweezers
vice
3rd hand

Step 3: Step 1: Gathering the Laser Diode


Here you have 2 options:
either to get a DVD drive for pc and extract only the diode assembly (aka sled).
or buy just the laser assembly from the internet.

You can get old DVD RW drives on ebay for >15usd, or just look around and ask friends if they don't have some old unused drives.
The another option is to buy just the sled ftom internet.

My favourite e-shops for laser components:
http://modwerx.com/shop/
http://hightechdealz.com/
http://stonetek.org/shop/
on these sites search for LPC-815, this is the most commonly used red laser (22x write speed).

What if I can't find the LPC-815, if I have only 20x or 16x burner, or if I'm not able to determine the write speed?
First, use google to find out something about your drive (search for part numbers from the label), this should bring out enough information. Remember the write speed.

You must extract the diode from the sled. This video shows the process:


if you have other model of dvd burner, set your DMM to the DIODE TEST mode and test both diodes using the pinout below. When you see bright red light, you've got your diode :)

Step 4: Step 2: Collimation Optics

This is needed to make the actual laser beam. Without this lens, you would have just a very wide, useless spot.
The most common colimator is  called Aixiz module, and it serves as the holder for both the diode and lens.
The diode is being press-fit into the module, using vice (see the pics).
You can buy it from the e-shops I mentioned in previous step

Step 5: Step 3: Driver

What's this?
This is used to regulate the current flowing through the diode.

Do I need this?
YES! You must NEVER connect the LD directly to the power supply because it WILL die!

Can I just use a resistor?
Theoretically yes, but the current will not stay constant as the components heat up and the battery voltage decreases and this can shorten the diode's life.

But kipkay didn't use any driver...
Why do you think we have to deal with n00bs crying about their dead Laser Burning Flashlight Hack? (Just read the text above...)

UPDATE
A lot of people ask me about the diode's forward voltage stuff. This is a constant current driver. That means, it will adjust it's output voltage in order to keep the optput current fixed. So, it doesn't matter if you connect a red (2.2V), IR (2V), 405nm or a 445nm (>4V), as long as your power supply's voltage is above the diode's voltage + 1.5V, your laser will be running fine at the set current.
Also, the answer to question: "What voltage is diode XY?" can't be answered directly. Every diode's forward voltage (Vf) depends on her type and on the current. For example, a LPC-815 has Vf from 1.8V up to about 3.2V, as the current increases. Every diode has a PIV plot, which describes it's dependancy between the current, optical power and voltage. Google your diode's PIV plot, such as "LPC-815 PIV" or "22x red PIV" and so on.
Since we're building a red laser here (based on LPC-815), here's the PIV plot for LPC-815: http://www.diy-lasers.com/images/LEC_LPC-815-red.png

You can either buy one or build one (if you can)
the most common commercially sold drivers are:
http://www.modwerx.com/shop/laser-diode-drivers-test-loads-c-10/adjustable-laser-diode-driver-circuit-assembled-red-or-blu-ray-p-8?zenid=heee48kk0ak9008r2v8oo60cn7
and
http://laserpointerforums.com/f64/lava-micro-flexdrive-driver-lavadrive2-fits-pens-22502.html (usage instructions: http://hacylon.case.edu/ebay/laser_diode/MicroFlexDrive_V5_manual.pdf)

The most common DIY driver is called DDL driver and it uses LM317 as current regulator.

you will also need a thing called TEST LOAD, which consists of 4 1N4007 diodes and 1 1ohm resistor wired in series (check the pics). To use it, connect the output terminals of driver to test load (+ on the diode's anode, - to the resistor) and measure the voltage across the resistor. With 1ohm resistor, 1mV of voltage equals to 1mA flowing through the setup. Now rotate the small potentiometer, until the DMM reading matches your desired current.

recommended currens for various diodes:
16x...200-250mA...<200mW
22x...300-400mA...250-300mW

Step 6: Step 4: Power Supply

Most beginners use 9V battery to power their first build, but 9V batteries have very small capacity and can't supply high currents (>350mA) for long times. Laser with 9V
battery at 350mA will burn for the first 60 seconds or so and after that the laser stays at <100mW and can't burn anything.
Now you must decide, if you want to build a portable laser or "labby" style, which just sits on the desk, powered by wall PSU.
The second option is easier, any wall PSU that puts out at least 8V at 500mA
If you want a portable build, the best option is to use Li-Ion batteries. The most popular are the 18650 's, but there aren't any battery holders for 18650, so easier is to use
14500 (AA size) or 10440 (AAA size), which can be used with standart AA/AAA holders. Don't forget to buy a proper charger .
Now, just connect it together using the schematic below. Pay attention to the pinout, if you connect it wrong, the diode WILL die

Step 7: Step 5: Final Phase


The last thing you need (or you should have) is the heatsink. Just find some small heatsink (good heatsinks are usually inside old CRT monitors), on which you can easily mount your laser module. Thermal epoxy (like Arctic Silver) is your friend :)
Or you can buy this one: http://www.laserlands.net/heatsink-12mm-yh.html

Now, let your imagination take over and build all this stuff into some nice project box.

Step 8: And What Now?


2 People Made This Project!

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63 Discussions

Hi, so I got a 1 watt 405 nm laser diode with the aizix moduoe with two cables... also the website said it operates on 5 Volts. What are the blu ray values? Also since it is a 1 Watt laser diode should I change anything else? Thanks in advance!

1 reply

how to make small laser hair removal machine. Like this handy machine or very laser hair removal machine

I did'nt see it mentioned anywhere about keeping the tab on the LM317 away from the laser diode case.

The tab is connected to the Positive Output of the 317 and the laser case is Negative/Ground. If they touch you would get a short circuit.

In one of your photos it looks like they are touching each other.

2 replies

Yes, that's right. It's not shown very well in that photo (step 7, photo 2), but the LM317 is actually insulated by a heat sink gasket and the bolt also has an plastic insulating washer.

Ok 3zuli. Thats good to know.

0
user
anjoze

2 years ago

I'm trying to reproduce the laser driver. It turns on but the laser doesn't burn anything.

The design is the same and the laser switch on and it can get to 240mA. If I change the 2 resistors (10ohms) for 3 I can have 350mA. Even like that It doesn't burn... :(

My AIXIZ module is this

Thanks for any help

1 reply

If you're sure that you used a diode from a DVD-RW drive (not a DVD-ROM, those don't have enough power), then it looks like the diode is damaged. It could have been either mechanical or electrostatic damage (ESD) during removing the diode from the drive, ESD or overheating during soldering, or the initial current was simply set too high and it destroyed the diode. After any of those events, the laser diode breaks down and keeps operating as a LED diode, but has minimal output power, so that's why it doesn't burn anything. Just get a new DVD-RW drive (or just the laser assembly itself) and try again, eventually you'll get it right :)

Hi,

can someone help me here please ?

I had 4 red laser diodes form DVD readers/burners. I used exacly this LM317 driver

http://laserpointerforums.com/attachments/f44/33304d1308798339-small-modification-lm317-drivers-driver-250ma-out.jpg

connected to 7.5V 1.5A power supply.

I set the driver to produce around 60mA. All 4 diodes were OK. The problem was all 4 diodes after 20sec just reduced their brightness for around 10%. After 2 diodes i thought the diodes just getting damaged from heat. But i tried to hold the third and fourth diode in hand without heatsink and they weren't even heating ! And same thing happened.

This issue is permanent for the diodes and it happened to me also with more powerful IR diode.

Any ideas ?

Thanks a lot !

4 replies

You must know the operational power of the diode and adjust control circuit accordingly.

When you slightly damage laser diode, it starts to function as a normal LED (it becomes trash). Perhaps that is what happened to you and you didn't notice heat output after.

Also LM317 adjusts voltage so that correct current flows through and if diodes's resistance went up, LM317 could've run out of input voltage (diode demanded more than 7.5V - 1.7V [Lm317 takes that much for itself]).

You must know the operational power of the diode and adjust control circuit accordingly.

When you slightly damage laser diode, it starts to function as a normal LED (it becomes trash). Perhaps that is what happened to you and you didn't notice heat output after.

Also LM317 adjusts voltage so that correct current flows through and if diodes's resistance went up, LM317 could've run out of input voltage (diode demanded more than 7.5V - 1.7V [Lm317 takes that much for itself]).

60 mA is probably not enough to power your diodes. The current may differ between diodes, so check the datasheets.

Great job man! hope you keep it up

Hi, This is the "Sony DVD-RW : DRI-190A" laser part which wirtes DVDs on 20x, i want its laser for using in mini CNC machine, but there is two laser diode in this model, i cant distinguish which one should i use, and i dont know about the model of laser diode too, any idea?
Left one, or Right one?


<I know i can test them and select the stronger one, but i just wanted your ideas>

sony.jpgsony1.jpg

just for clarification, how is the test circuit suppose to be used? just hook it up the the driver circuit to check the resistance right?

hello sir ,
i am working on same project

i used dvd rw laser for my project. I follow the circuit diagram given above but laser is not upto the mark not focus and not burning paper or any other things. Is this problem is due to lens that i havent used yet or any other thing ?

plz help

1 reply

You need to use a focusing lens in order for the laser to burn stuff. Otherwise you just get a wide beam which is very weak.