Picture of How to build a laser (general guide)
red laser.jpg

Step 1: What do I need to build a laser?

Basically, you need:
laser diode (LD)
collimation optics
current regulator (aka driver)
power supply
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
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marek.sefl.36 months ago


can someone help me here please ?

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


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 !

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

I know almost nothing about lasers but maybe the voltage they were getting was too high

E1024d2 months ago


how to connect three legs of VR


aephy65 months ago

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>

zepplica5 months ago

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?

gul.m.rafiq6 months ago

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

3zuli (author)  gul.m.rafiq6 months ago
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.
john1a made it!1 year ago

I Made it! Actually I made all this laser using a NDV 4542 405nm diode at 120mA using this driver. I also made gerbers (PCB schematic) for this driver and uploaded it in this comment.

You can see my build (CNC Laser Engraver) in my profile.

Your LM317T schematic is WRONG, my friend!


Middle leg is the output leg.

3zuli (author)  yamahapower1 year ago

This schematic is OK. Your schematic is the LM317 as a constant voltage source, which can not be used to drive laser diodes.

In this case the LM317 is connected as a constant current source: http://www.ae5d.com/images/Lim.png

The current goes from the OUT pin, passes through the resistors creating a voltage drop, which is then sensed by the ADJ pin and compared to the internal 1.25V reference. LM317 will adjust its output voltage to get 1.25V on its ADJ pin, which in this connection results in a constant current supply.

Quin51 year ago

I'm looking to purchase a lazertag system to start a lazertag business,
would you be able to produce or lead me to the guns and equipment I need
that would be safe and certifiable, that would be a cheaper option than
the $600/gun price range that I've seen advertised by the lazertag
manufacturers? email if so at ulrichinvesting@gmail.com

3zuli (author)  Quin51 year ago

This is the cheapest lasertag I know about: https://www.kickstarter.com/projects/skirmos/skir...


It will cost $119 per gun (DIY kit), but it's still in development. However if you want to make a business, I would rather rely on ready-made lasertag systems which are already certified, reliable and safe to use. As a lasertag business, the last thing you want to deal with are blind customers.

PLZZZZZ clarify my doubts

1>want to know that if I use Li-Ion batteries i.e; 18650 which are 3.7v 2600maH,then I have to use 3 of them connected in Series is that right(about 11.1 v )(since the total consumption will be about 7.2v),but these batteries comes with pcb protection so when I will be using this laser will the pcb should posses any problem.Secondly want to know that if this driver can handle 2600mah.

2>Then in case 14500 which is standard AA(1.5)then have to use 5 of them I guess,plz clarify if I am right or wrong.

3>Can u plz give the names of the chargers which charges these batteries,1 by 1 charging will not be a problem for me.

4>plz suggest the best lion battery manufacturers. I went to this site(http://www.candlepowerforums.com/vb/showthread.php?257543-LiIon-18650-battery-comparison)but cant decide which one to purchase.

Thankx in advance

3zuli (author)  Dimitrioptimus4 years ago
1. what diode are you using? because for red or IR laser 2 LiIon's are enough, but for bluray or 445nm you need 3 batteries. Also, don't forget to properly heatsink the LM317, it will get toasty ;) The protection PCB is mostly your friend, it just monitors the battery and keeps it from under- and overcharging and disconnects the load, if the current is too big. The 2600mAh number is the capacity of battery, the higher, the better - the more power can be stored inside and the longer is the runtime.

2. 14500's are 3.7V LiIon's too, so you have to use 2 or 3 of them

3. I'm using this one: http://www.dealextreme.com/p/trustfire-tr-001-multi-purpose-lithium-battery-charger-12594 It's a bit slow but works, this one is quick charger (and can fit some bigger batteries too): http://www.dealextreme.com/p/ultrafire-wf-188-rapid-charger-for-3-2v-3-7v-lithium-batteries-100-240v-44091

4. You don't have to use those $15 AW IMR batteries, in fact those cheap 18650's and 14500's I linked in this step are good enough (I'm using both, drawing 1.5A from 18650 and 0.8A from 2 14500's in series and they preform well)
hope I helped you :)
Quin5 3zuli1 year ago

I'm looking to purchase a lazertag system to start a lazertag business,
would you be able to produce or lead me to the guns and equipment I need
that would be safe and certifiable, that would be a cheaper option than
the $600/gun price range that I've seen advertised by the lazertag
manufacturers? email if so at ulrichinvesting@gmail.com

CCube551 year ago
can I use the G9105 regulator???
3zuli (author)  CCube551 year ago

G9105 is a 5V fixed voltage regulator. I've seen some people build laser drivers using fixed regulators, but I don't think it's the best idea. Adjustable regulators such as LM317 are way better for this. If you are interested in the low dropout voltage, try the LM1117 which is a low-dropout variant of LM317.

brooksby1 year ago

I cant get a 35mw laser diode burning with the standard laser circuit ie.9v lm31t.

what could the problem be?

3zuli (author)  brooksby1 year ago

35mW is not enough for burning. Generally you need at least 100mW to burn stuff, so I recommend you to buy a stronger diode.

for metal cutting what i can do...?
army_knife2 years ago
Hi, I want to build a ~150mW 532nm green laser, but am not quite sure how to.
I have a flashlight housing with 2x 3.7V batteries, which i bet I can fit the laser into
I want to buy all the pieces online so that I can assemble the laser when they arrive,
but seems like no one is selling a laser diode nor driver,
I am want to spend <35$,
is this possible? if so, can you reffer to a ebay seller, or maybe share some links?
3zuli (author)  army_knife2 years ago
This is not possible for < $35 (unless you get the module as a gift from someone :D ). Just the laser module will cost you $40-50, for example this one: http://dx.com/p/200mw-532nm-green-laser-module-3v-11-9mm-26891?r=93098389 , which should output 100-150mW.
These modules can't handle 2 3.7V batteries, so you can either replace the original driver with one that can run from 7.4V, or you can build a spacer that will fit inside the battery tube and will replace one of the batteries, so that you only get 3.7V. It's also recommended to connect a diode (1N4007) in series with the module, because some modules might get burned from fully charged LiIon cells (4.2V) and the diode reduces the voltage by about 0.6V.
I recommend you to go to laserpointerforums.com and view the Green lasers section and try searching for "green laser tutorial" or so, I am sure you will find lots of informaton and ideas for your build :)
Hamzafarooq2 years ago
what is the voltage & Amps of a red laser diode?
(I am using a 22x HP DVD R\W Drive red laser diode...)
3zuli (author)  Hamzafarooq2 years ago
Start at 300mA to be safe.
HFraza3 years ago
please tell me the voltage of laser diode
or +7.2V
3zuli (author)  HFraza3 years ago
what diode are you using?
Electorials4 years ago
"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?"

lol that was funny :D

There's something I don't really understand:

In these examples, it means that the diode will run at
U=P/I = 200mW/250mA = 0.80V
U=P/I = 300mW/400mA = 0.75V

Isn't that voltage Really low?
Datasheets say that a dvd burner diode runs at +- 4V ?!

Also, the power (e.g. 200mW) is that electrical or optical power?
3zuli (author)  Electorials4 years ago
the power I'm talking about is the optical output from laser diode. the electrical power is greater.

And what is the average efficiency value of a DVD burner diode?
(Output power / Input power)
3zuli (author)  Electorials4 years ago
I don't remember the exact efficiency, each type of diode is a bit different. for example, this graph is for lpc815 (22x) burner diode
Ok, Thank you ;)
how to make it without module
HFraza3 years ago
please tell me the voltage of laser burner
cas24063 years ago
hi there

i did every thing as you did but i can't get the laser to burn, could you please help me? i used the same parts (laser diode, parts for the driver).

3zuli (author)  cas24063 years ago
1. what PSU are you using?
2. is the laser focused?
cas2406 3zuli3 years ago
I am using a dell PS-5161-1D PSU
Output: at 5V, max 11A, 85W max
at 12V, 9A max, 160W max.
i have tested at both voltage. and the beam is focused
Dreistein3 years ago
do u really need to use a module?
3zuli (author)  Dreistein3 years ago
well, you don't have to, but it's just so much easier to use one, and they are pretty cheap (around $4)
can i use the power from a tomcat torch and/or a 3v power suply?
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