Burning Laser With Joule Thief





Introduction: Burning Laser With Joule Thief

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..



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    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?

    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.

    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! :-)

    Thanks for your valueable comment. Agreed on your view.