Burning Laser With Joule Thief




Introduction: Burning Laser With Joule Thief

About: The flow of electrons fascinates me the same way it make a bulb glow.

Take care of Eyes since these lasers are lethal for eyes. It can blind you before your eye lid will close. --- I am Not responsible for any damage.

Please Go through http://en.wikipedia.org/wiki/Laser_safety before reading and come to any determination about the topic.

We can burn things specially black or dark colored stuff by simple 3V battery but this will heat up the diode after intensive use. In case we need to make a Laser engraver which needs to operate over long time, Requires assembly to cool the diode down. How ever by using Joule Thief we can increase its brightness and eventually draw the heat away from diode to the transistor used. In fact I was able to run a 12V 10 Watt LED with a single MOSFET , It was very bright , using a third winding.the video is

How ever the Mosfet got very heated and unnoticed by me . Died.....!!!

Anyway I am still finding such MOSFET for Laser Applications.

For High Voltage generation visit


Step 1: Setting Up Components

The basic requirement is any NPN transistor, a Laser Diode, a Ferrite ring,a resistance,A 3 V battery,Bread Board , Wires.etc.

The pin Configuration of BD139 is Front Facing E-C-B.

However any NPN transistor can be used.

Step 2: The Circuit of Joule Thief.

You may find this diagram every where throughout internet.The working principal is also as same as explained by others.

Step 3: The Laser Diode

This is specifically a Infra-Red Laser found inside a DVD Burner. I removed all optics and finally wanted to fix with the focusing lens. We can use any lens depending upon requirement and focusing length.

Step 4: The Toroid , the Heart......

This toroid was found from a CFL driver. 3 Turns each for each Winding. If the figure does not work out. Reverse the wire. i.e interchange the Blue and Violate wires.

Please try to understand the winding. If understood correctly, we can use any toroidal ring for the same purpose. Please Note that Torroidal Ring used in good SMPS have good performance against high frequency.

Step 5: All Connected and Its On

Connect every thing as per Circuit diagram.

IR laser from DVD/CD Burner connected to Joule Thief with BD139 and a 10K variable resistance. It can burn any black or dark color plastic,rubber etc. Take care of Eyes since these laser are lethal for eyes. It can blind you before your eye lid will close. --- I am Not responsible for any damage

You can take red laser or high power leds. Please also note to limit the supply voltage to 3 Volt Max else you will damage the diode. These diodes can bear 3.3V Max.

Step 6: Its Ready and Burning....................

Take care of Eyes since these lasers are lethal for eyes. It can blind you before your eye lid will close. --- I am Not responsible for any damage.

Hope you will Enjoy...... Take Care..



    • Tiny Home Contest

      Tiny Home Contest
    • Fix It! Contest

      Fix It! Contest
    • Metalworking Contest

      Metalworking Contest

    52 Discussions

    This instructable seems to have started a fundamental discussion, about what information should be easily available.

    I used to work with laser cutters with IR-Sources up to 120W. These are really dangerous, if handled the wrong way. (High voltage, IR-Radiation) What is certainly underestimated by untrained personel, is stray radiation. The retina is serverely and permanently damaged, even by a stray ray of 0.01% of the laser energy. We lit a cloth with the laser during training. (With the unfocused half inch laser ray. Imagine what it does focused...)

    Until a couple of years ago, no country restricted the import of
    powerful laser pointers. These were about the same, as in this
    instructable. But ready out of the box, with a decent optic and usable by every idiot.

    But then, there are so many "dual use" tech products, which are very interesting to tinker around.

    You can't make them go away, by banning them from sites like instructables.

    If the stuff is available, there is information available about it nowadays. If not on instructables anymore, you can find it elsewhere.

    So the final question should be: Do you want freedom, or (a wrong sense of) security?

    3 replies

    I also concern a lot about this. That's why I still do not want to try it. Is there any other ways to prevent the laser from reflect to unwanted objects rather than using safety glass, like some materials to make a case that absorb the energy?

    Do yourself a favour and get protection goggles for the correct wavelength. Only this way you are on the safe side.

    Engraving with 400-500 mW? This will be a very slow process. So keep the Dremel close ;-)

    Use black covering , non reflective type cartboard. U can use web cam as an eye inside such closure.

    Thanks! Takes place one on my projects list!

    made it ,the circuit is simple and works,done some tinkering and 12 volt smd led is working ,but i dont know how to use 7805 voltage regulator for mobile charging.

    1 reply

    I hope you had already figured out how to use 7805 for mobile charging. Use a capacitor before the Input to 7805 about 10000uf/250V and arounf 250uF/6V in the output . so as to charge it and then it will make a 5V for the mobile phone

    I just want someone to build a laser mower. improbable?

    Good stuff!

    You might want to consider putting the warning about it burning an eye as the first bit of text. It'd be a shame to have someone injure themselves or their cat because they're too impatient to read to the end prior to building.

    Thanks for putting this up! :-)

    5 replies

    Thanks for your valueable comment. Agreed on your view.


    Reply 3 years ago

    Did U know Soldering Iron ? Whats its Safety Sandard? What ever , u can do solder your circuit and also burn your cloths, lit a matchstick and burn someones house. That will penalise the man who however invented Soldering Iron and also arrestbthe people selling it. I don't understand why people are not conserned about the simplicity of the project rather than the complexcity of the standard. Use it care fully. Use a Mobile camera to detect a beam. Use safety Goggles designed to handle this type of radiation.

    Yes, a typical temperature-controlled soldering iron with a range 250°C –
    450°C is hot enough to ignite clothing or other Class A combustible materials (wood,
    paper, cloth, rubber, and plastics), but it's not a common occurrence. In other words, you can't easily burn down a house with a soldering iron (unlike, say, a matchstick or lighter) - the best you can do is melt a hole in your shirt, pants or carpet. By then, hopefully, you realize you've dropped the iron in your lap or left it on while you went to check on the pizza and it fell on the floor.

    Granted, someone burning their retina with a laser isn't common either. It's just the laser causes so much more irreversible, immediate damage than a soldering iron can cause. So there's no comparison really.

    We don't have to argue about this any longer. My last comment is a question...if it's so obvious you (like the soldering iron inventor) shouldn't be held responsible for accidents caused by the laser, then why do you feel it's necessary to include your underlined, bold, italicized disclaimer? "I'm not responsible for any [of your eye] damage"

    as for the disclaimer, it's probably unnecessary, but just good to have anyways

    output power of burning laser depend on what ??? can i. make a burning laser from keychaiaser diode !!

    I am confused as to how the ferrite ring has these induction properties. I can't seem to find a good explanation as to how this works.

    What if you used this for a (very weak and slow) laser cutter with recycled computer parts? With this (https://sites.google.com/site/0miker0/home) as the body. Someone already made a 3d printer based on this. I wanted to, but don't have enough to spend. I do, on the other hand, have computer parts.

    If you wanted to (he recycled 2 dvd or cd drives) you could probably just use multiple lasers and angle them so they all focused on the same point.

    Here's another guy who used the same type of body: http://builders.reprap.org/2010/08/selective-laser-sintering-part-8.html

    And the odds of anyone building this without already having basic knowledge of lasers is..?
    But, yeah, somebody sued McDonald's for offering-up hot coffee

    1 reply

    Hi All!

    I dont want to be limited in spreading technical knowledge just because
    of security reasons - this is mainly because "security reasons" are
    often used as an excuse for some other intentions behind that ...

    But I need to ask you all:
    Do you really think that a smart kid who understands this instructions
    will sneak into father's electronic lab to do some experiments and
    do you think that he will apply all the safety guidelines ?

    My concerns are about the young people and about the silly
    people who are phsically adult but are not mentally adult.

    I really dont know a solution to this problems and I have no idea how
    to deal with it so that common knowledge flow will still be possible in future.

    But if any one knows the solution on how to share information freely
    amongst "trustworthy" and "rationally thinking" persons then I will
    be glad to read it here and I will be glad to spread this idea wherever I can.

    Gerald Trost
    PS: can kids access the instuctables pages ?