Build a cutting laser from an old PC

[Drake Anthony] makes building a cutting laser from a PC look easy, and it seems like it actually is. Almost everything you need can be found in a dead desktop unit. The diode is pulled from a DVD writer (16x or faster), with the power supply unit, and heat sinks from the processor and GPU being used as well. You’ll also need a focusing lens (just a few dollars), some thermal glue, an LM317, a resistor, and a pair of protective goggles matching the laser diode’s wavelength.

He fits the diode into the lens, then glues the assembly into a hole drilled through the processor heat sink. A driver is built using the LM317 variable regulator, resistor, power supply, and the GPU heat sink to keep things cool. Check out the video after the break to see the laser cutting tape, burning plastic, and lighting matches.

Comments

  1. grenadier says:

    OLD!

  2. will says:

    neat, and grenadier is a troll ^_^

  3. Terc says:

    Burning hand at 3:29

  4. xeracy says:

    @terc – saw that too.. lit the matches then stuck his hand in front of the beam to show em off.

    any one fancy a guess as to the laser’s wattage? or what its being over-driven to?

  5. Pedro says:

    That heatsink doesn’t look like it’s a very good fit. He should have under-sized the hole a little and hammered it in there with the thermal glue.

    A smaller and more efficient power supply might be nice, too, but reuse what you’ve got I suppose!

  6. jeditalian says:

    so.. i would be better off with a bluray burner, right, if i just want a fancy cigarette lighter?
    at least i learned how to activate the newer PSU’s, bc i forgot how i use to doit with a paperclip

  7. lee says:

    What about leaving the fan on the heatsink and wiring it to the PSU, then you’ll be able to use it forever, right? heh heh…

  8. lordicewind says:

    @xeracy – output power is somewhere between 100 and 200mW, probably. Depends on the speed factor of the burner.

    Also, I don’t think that you can overdrive it much in continuous mode, especially if you don’t make use of the beam monitoring diode. Most laser diodes don’t like it for thermal reasons. It might be possible if pulsed, though.

  9. dumbass says:

    this is highly irresponsible! you really suck!

    a laserist

  10. Cynyr says:

    hmm “cutting” laser might be a bit of a stretch, but still a cool build. I was hoping he was cutting plate steel or Al sheet, but alas, i need to save more pennies.

  11. Leithoa says:

    Just rescue 20 of these and aim them at the same point. You could power a few(4-6) of these off the same PSU without too much trouble.
    If you get them for free or nearly so it might actually be worth the time and expense spent on making a bulk mounting/aiming bracket.

  12. cgmark says:

    Serious overkill.
    The laser diode doesn’t generate enough heat to need that heatsink, a 20W laser doesn’t use one that big. The heatsink it is mounted to inside the drive is big enough. For power the lm317 isn’t needed. Use the 3.3V power from the power supply and feed it through a resistor. Output is around 120mw for dvd burners at 2.4V.

  13. sarsface says:

    Looks about as powerful as a magnifying glass in the sun.

  14. cgmark says:

    Power consumption for a laser diode out of a dvd recorder is so low that a typical pc power supply can run 100+ dvd sized diodes without breaking a sweat.

  15. gmc says:

    @Leithoa – would the combined output from multiple lasers still be coherent? – Wouldn’t there be phase-cancelling issues?

  16. bobdole says:

    “Looks about as powerful as a magnifying glass in the sun.”

    Well that would depend on how big the magnifying glass is. This laser is about a fifth of a watt. If you had a 1m^2 magnifying glass, it would be delivering 1000 watts of power.

  17. j says:

    I love the chainsaw for extracting the heat sinks

  18. Jesse says:

    Not that it matters, but I think he’s using the NorthBridge heatsink and not the GPU heatsink

  19. Matt says:

    Totally puts his hand in the path at 2:28!!!

  20. tom says:

    All of you people are seeming to forget is that he is just using available parts. Still a pretty nice hack for repurposing old parts though.

  21. Garbz says:

    @Jesse, He pulled the northbridge heatsink off too, but it was half the size. Regardless of which I don’t think you’d need much of a heatsink at all. Those Axis modules work rather well dissipating the heat.

    @cgmark, constant current drivers are important for driving lasers. A DVD laser may be fine, but a bluray laser has an incredibly steep I/V curve. Variances in laser diode construction produce different voltage drops and with resistor values and voltage drops that low you could quite easily use the resistor for one laser diode just fine, and then blow the next, especially when you run the laser at it’s limit.

  22. Leithoa says:

    @Gmc
    I’m going to assume that there would be some amount of interference, but I have no idea how much. Assuming you’re driving them at the same voltage/current and the diode tolerances are pretty tight the light should be fairly monochromatic so there wouldn’t be too much loss due to that but so I guess most of the losses would be due to the mount and orientation of the diodes.
    They’re using multiple lasers to try and drive fusion reactors so the problem isn’t unsurmountable. It just depends how much math you want to do, it would probably be easier to add a few more diodes to make up for losses.

    @cgmark
    I was basing my guesstimate on an old psu I had lying around which had 12v @ 9.5A through the yellow and the max current a Lm317 can handle 1.6A. So the number of diodes will vary depending on the size of the PSU, and obviously current from the diode.

  23. medwardl says:

    I’m still waiting for someone to figure out how to build a cheap laser cutter that can cut steel.

  24. i am impressed with this simple, yet very useful hack ( though a bit risky ).

    Come on people, cutting steel with a 50 cent laser diode is not possible !

    I would say, it can make a great CNC for cutting things like styrofoam.

  25. Whatnot says:

    So I’m curios, how far away does the coherence last on his setup you think? At what distance could he still burn the tape?

    I’m trying to catch this roadrunner you see.

    (And the other commenter was right BtW, the laser-from-a-drive thing is now pretty old and there must be a over a hundred youtubes alone on the subject.)

  26. I’m the creator of this video and I’m here to answer some questions.

    This build gives you around 250mW or so, it’s pushing the laser diode a bit but should still be OK for long periods of time.

    You can pull off burning tricks from up to 25ft or so with careful focusing.

    Yeah the heatsink is overkill, but the whole goal is to build a laser from a dead computer.

    The laser didn’t burn me because it is red, red light gets distributed through the red flesh so it doesn’t cause burns easily. If it were blue or green that would be a different story.

  27. cgmark says:

    @Garbz
    I make driver circuits for 10W and 20W lasers so I’m familiar with what they require. bluray lasers will work fine off resistors alone but if you need current control the cheapest way is a transistors and resistors. The common PN2222A will do the job .

    Diode lasers are nowhere near as complex as when we had to use high voltage and gas filled tubes with water and refrigerant cooling.

    Using multiple lasers for a single source isn’t all that hard if you have the money to spend on the optics. The quality of optics is really all over the place depending on your budget.

  28. medix says:

    … or you could just use a couple of fiber-based power combiners. They’re not that expensive.

    Coherence is a function the spectral width of the laser:

    http://en.wikipedia.org/wiki/Coherence_length

  29. medix says:

    er, I should say ‘inversely proportional to’ the spectral width. Narrower linewidth = longer coherence length.

  30. Jack says:

    Laser in dvd/blueray drives isn’t strong to do anything useful with it at all. I dont really like this video with no music btw and the ‘idiot’ put his hand in the laser light as well.

  31. asanthai says:

    this makes me want to build one of those computer-controlled laser paper cutters.

  32. Abbott says:

    So if I were to use a PWM supply on this, couldn’t I theoretically get much more power out of it by pulsing it at higher voltages?

  33. Osgeld says:

    no abbot, you would get intense pulses but probably the same overall average once its said and done

    its like using a machine gun in place of a cannon

  34. Abbott says:

    Hmm, fair enough. Oh well, this would probably be powerful enough to (very slowly) burn some designs into leather, perhaps wood too.

  35. avrpunk says:

    @medward1 Cheap lasers that cut steel are typically CO2 laser tubes sourced from China. Water cooled, buy a bottle of CO2 (most gas supply places actually have the proper mix for lasers), a regulator, the transformer, and you’re in business. There are also sealed units that don’t need flowing CO2 but they have less power.

    You could probably get started cutting metal for about $600, with a self-built CNC setup at around $3000.

  36. Localghost says:

    @Abbott,

    You will be able to burn leather, I have done this using DVD diodes, but you need some goggles, or a CNC type thing :),
    Or, use a webcam to look at the laser behind your LCD and just look at your LCD with your hands behind it, (Like working with one of those biohazard chambers with gloves)…
    It works well for IR diodes too, cause the webcam can see those :)

  37. sxrysafis says:

    On a similar note to Abbott’s: Could this be modulated (via PWM or such) so as the beam to be visible in the air, while itself being harmless?

  38. Tachikoma says:

    I realise this video focuses on cheap laser construction… and hats off to that. But I can’t help bitching about the fact that too many youtube vids demonstrate lasers with burning tapes, matches and balloons. Would be more interesting to see actual experiments that require powerful lasers…

  39. /me says:

    At least 16x DVD writer? That’s not a component you may find in an old pc.

  40. Virgin Hack says:

    I think I will make this my first proper hackaday hack. And might even post info on how it goes. Wish me luck and be very patient it will probably take me a very long time to bother to start.

  41. Brad Hein says:

    He demonstrates the laser cutting tape, lighting matches, and then sets his hand in the beam. Brilliant.

  42. Whatnot says:

    Thanks for giving some answers and info Drake.

  43. Leithoa says:

    @ Brad
    As the creator has already stated a red laser is bad at burning red/pink flesh. Enough of the laser is reflected/scattered when it hits your flesh to be a poor wavelength for burning you. In industrial processes they use different wavelengths for cutting different materials.
    In Terms of overall wavelength energy (N)IR/red have the lowest energy with blue/UV having a lot of energy, enough so to break bonds on a molecular level and cause mutations in DNA ie; skin cancer from sun bathing.

  44. bilbao bob says:

    As a kid, I found a big fresnel lens designed to turn a 19″ TV screen into something, uh, bigger, I guess. A few pine boards to make a frame and I discovered it could fry things much larger than ants. If the sun was in the right place, anyway.

    It turns out that 4 ~300 watt photoflood bulbs in metal reflectors, a used box fan and some 2×4 stock makes a very effective portable death-ray, at least for small enough values of death.

    Welder’s goggles are a must, but the budding mad scientist must remember that when you’re the only guy with a racoon tan in a place without ski hills.

    Also, attempting to double the power to eight bulbs teaches you a lot about circuit breakers and introduces you to the physics of waste heat faster than you can say “Did you see that? It exploded!” and start picking fresnel lens shards out of the back yard.

    You know, I’ll bet the arduino guys look at me like I look back at the teenagers who played with dynamite.

    I’m pretty certain that when my little grand-daughter gets sent home from school for setting up a plasma disruptor field on the playground, I’ll be there to console her with ice cream, a largish bag of dilithium rock tailings and an explanation of how we can grow crystals in the oven.

  45. cryptocrypto says:

    you are all stupid…a dead desktop most likely means that the psu is dead….how the f*ck are you going to power a laser diode with a dead power supply….

    • Erik says:

      “most likely”. You don’t even know whether what you’re saying is true, but yeah, you must be more correct than all these people who have talked very knowledegably about it for ages.

  46. Presto says:

    Yes an old idea but still impressive in the way that it was put together, very resourceful and intelligent! I think that this particular design would be great for soldering because of the extended use ability and if it can generate enough heat to melt solder that would be awesome!! Nice design Drake!

  47. Hoang Quoc Khuong says:

    yes,this movie is ok, but how can we increase the watt for this laser source only using some DVD write laser diode and mirror, lens???
    pleased, clarify regards this matter!, thanks so much.

  48. harry says:

    I wonder if I were about to use a PWM supply on this, could I theoretically get much more power out of it by pulsing it at higher voltages?

  49. Davis says:

    i am wanting to do the same thing but im not sure do i need to put a resistor on it and if so im not sure how to do that can anyone help me ?

  50. YeaSeb says:

    well, i’m working on that build but the aixiz module link is dead… could you tell me what module shall I need and where should I buy it?

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