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Experiments with DVD laser.

    The idea of the use of laser light-emitting diodes (LED) of the broken CD drives appeared in the forum not once… As far as I understood there were talks only, no actual experiments; perhaps it is for the better for someone… Thus, I disassembled RW-DVD, took a laser diode out of it, joined it together with a lens of a laser pointer and got the following result. You can lead interesting experiments over this device. Striking matches is not the most efficient variant. You can burn paper with it; having pointed the beam to a balloon you can see how it bursts. It is desirable that the balloon would be of dark colour, green or blue; red balloon doesn’t burst. A focused beam leaves a rather deep furrow on a black plastic; and makes a small spot of white or mirror colour in the focal point on transparent organic glass. If you fasten such diode to the head of a plotter, you can engrave the organic glass. It’s worth being thought over… Diode can also be fed with 500 hertz impulses. In such case its may capacity increase up to near 400 or 500 milliwatt, and this is serious. In a word, there is no end of work here…


    If somebody decides to make such laser super pointer, I reveal you some ruses. Not every DVD is good for such purpose, for example, Samsungs are not appropriate at all because their diodes don’t have cases and their crystal is not protected at all and can be put out of operation just by the touch to its edge… LG is the best variant; however different models of drives have different capacity of diodes. Power of the installed diode can be determined by the following drive’s characteristic: you should ascertain the speed of DVD writing two-layer disks; if it writes at the tenth the diode power is 180-200, if the speed is 16 the diode power is 250-270. And one more detail. All laser LEDs suffer from static a lot. Before taking diode out it’s necessary to solder a 1 megaohm resistor and ceramic capacitor of 470 nanofarad parallel to the pins. Solder obligatory with an earthed soldering iron. They are so sensitive to the static…I feed them with two Duracel batteries through a 2 ohm resistor. The current makes 170 milliampere. This is the limit for laser diodes.., though some samples manage to stand 200 ma. Heat remover must be used, as the diode stops working at overheating more than 50° C as well as at the current rise. It’s sensible to control the current. This sophisticated experiment wasn’t led without particular reason.., an idea arose to write volume holograms by means of this laser. Its capacity allows writing a 300 Х 400 mm hologram easily; the diodes’ coherence can reach one meter. And this is without Fabri-Pero model!

    And one more “small” reminding. Power is rather high and dangerous for eyes. Any ingress to the eyes results in burning several eye cells due to refraction in crystalline lens. Direct ingress causes loss of sight. A beam reflected from mirror surface is also dangerous. Diffused beam is less dangerous but has a bad effect on eyes anyway. Remember that any experiments with lasers are extremely dangerous and demand high level of proficiency.

I wish everyone good modding,

Silent computer
Modding technology
    My the second mod fashions......

My the second mod fashions......
Non-constructive thoughts about modding...

    All began when one day my neighbour, he is Automatic Control Engineer, came and started to beg me to give him one diode. When I asked him why, he typed modding in a search engine. And it had a great effect on me. I was sick about it. Maybe there is nothing accidental in the world and this modding seed fell into good soil. All my life I was interested in design.

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