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Thread: [n00b needs help] Problems with 200mW red laser diode

  1. #1
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    Default [n00b needs help] Problems with 200mW red laser diode

    I wanted to make a homemade red laser from an Axiz housing and a DVD burner Laser Diode. I saw the instructables tutorial and thought "oh, this is easy and cheap"... So I bought two broken DVD burners, an LG4167B and an LG4081B and extracted 3 laser diodes, one from the 4081B, and two from the 4167. But I broke one of the 4167 diodes, the powerful one, and I only had 2 ~5mW laser diodes, I tested it and worked fine, but in that moment I didn't know they were only 5mW diodes, but I suposed it so i bought a third VD burner, andother broken 4081B. When I dissasembled the burner, I realised that the powerful 4081 laser diode was in an strange package, with the controller attached to it, and useless for my project... so I bought a fourth DVD burner, this time a 4120B, which turned out to be as 4081, so, finally, I bought the fifht DVD burner. A 4167. I have dissasembled it and extracted succesfully both diodes. But when I test the powerful one, it doesn't light. I think it's not broken, because I can see a little red light spot inside, so I think the problem is in the batteries, but I have tested the diode with 2 AAA batteries, like in the instructables, and it still doesn't light well.

    And that's my problem. Do you think the diode is broken? How can I know if it is?
    It only lights a little bit, very very little.

    I'm very disappointed with this project. Nobody said that there are burners whithout power lasers in TO-18 case, and nobody said how to extract them, or how to put the new laser diode in the housing (they said using a pair of pliers, I have had to use a bank(table) screw (I don't know how to say this in English) with a special tool). So I've spent about $65 in broken burners (with shippement), $49 in safety googles and $15 in housings, and I have only 4 ~5mW laser diodes and 3 housings.
    I'm only a 16 years old Spanish studendt interested in electronics and lasers, and I don't wanna spend more money, so please help me if you can and answer in simple english, so I can understand. I think I will buy a 200 mW red laser diode from Axiz ($40) and I don't wanna break it. SO if you have some tips for me, or electronic schemes for I and V regulators, pelase, let me know.

    greetings from Spain, thanks for your answer!

  2. #2
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    You probably blew the diode(s). They often only emit a low red light when they are blown.

    I recommend using some kind of current regulator such as the die4drive during your experimentation so that you know how much current you using. Otherwise, you are just rolling the dice.

    Also, be careful with static when handling the diodes.

  3. #3
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    Yeah you are smoking them as soon as you put the batteries on. You must control the current going into the laser diode or you will kill it. Laser diodes look like short circuits to a power supply and will allow the power supply to dump as much current as it's capable of across the junction. Batteries directly connected tend to spike current also when connected directly to a laser diode sending it to diode heaven.

    Build a nice, cheap diode driver and use that for testing. Don't do direct battery connections.
    The Frothy Chimp
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  4. #4
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    Thank you, it's blown. I don't know what could have happened, I use ground-connected gloves to handle the diodes (the ones I use to clean the computer). I think that all happened in the extraction process. It was glued and I had to make force with a screwdriver... And I probably damaged it.

    Where can I buy a die4drive? How much is it? I have already spent all my pocket money in this project

    And other question: What happens to a diode if you invert + and -? I tested it with a 5mw diode, and nothing happened, it still works, but I have read that it damages the diodes... Why 5mW diodes aren't damaged?


    EDIT: for those who say that a current regulator is needed, check this (if it's spam, tell me and i'll erase it): http://www.instructables.com/id/Laser-Flashlight-Hack!!/
    I thought that a current regulator was needed, but in the isntructables nobody said nothing, so I connected the diodes directly to batteries... (like the instructables guy does) 5mW diodes still work, but I think 200mW one has a lower internal resistance... and now it's in heaven.

    Please, give me some schemes to make a current regulator, please.

  5. #5
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    Info on the die4drive and how to get one is here

    The link in your post is dead.

    Jim

  6. #6
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    Do a search here on the forum...there is one listed somewhere....also try Sam's laser faqs
    You are the only one that can make your dreams come true....and the only one that can stop them...A.M. Dietrich

  7. #7
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    Use a battery, not a power supply. That makes life easier. Charge the battery when the laser is NOT connected to it!

    If the battery is lead acid type, it will have a well behaved voltage. Lithium is also good, and to a slightly less extent, NiMH.

    A resistor is all you need, as an absolute minimum. Use Ohm's Law to calculate the value, same way as for LED's. Battery voltage minus diode voltage (usually 2.7V, so 9.3V from a 12V battery). Divide that total by the amount of AMPS, not milliamps, so maybe 0.2A wants a 46.5 ohm resistor. As 47 ohms is a major preferred value, you won't have trouble getting one. You also need to put a low ESR capacitor across the diode before powering it. Make sure the capacitor is FULLY discharged immediately before you try connecting it to the diode.

    If that's not clear, go over it until it is.

    There are far better systems, but that will at least get you past the instant diode death stage.

  8. #8
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    The correct link: http://www.instructables.com/id/Laser-Flashlight-Hack!!/

    I can't understand die4laser driver, I need a sheme, not photos. And I'll go better with something small to fit in Axiz case with SMD components

    I've read in instuctables and ther's a lot of people with flashlights worknig without current regulartor, from AA batteries (I used AAA). So I think that wasn't my problem. The diode probably was blown before testing it. (Maybe damaged when solderng longer leads, or when exxtacted)

    Other thing: I tested the diode in the flashlight, which outputs 2.4V (it's written in the case) from 2 AAA batteries, to drive a bulb. So the resistor (or somethign similar) was already there.

  9. #9
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    You never mentioned a resistor, so you probably blew them with overcurrent. Don't ever rely on a battery's internal resistance to protect a diode. Read my post, it's there to help, not to waste your time.

    If you go back to the Die4drive page, you will see there IS a schematic. It's in a PDF file download. It's the first link on the page. You'll need to attend to details if you want to avoid wasting more money and effort.

  10. #10
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    dont know if this is going to help but i put two of the doctors rohm diodes into two flash lights i never used a resitor of any type also the batterys i used were new duracell batterys giving 3.2 volts and they work fine on a duty cycle of 30 seconds on and 30 seconds on i could push it harder but i only built these to see if i could( we do them sort of things here on PL)anyway i would surjest that you use a rechargeable battery like a pair of ni-mh that would give you around 2.4 volt fully charged also the diode should only take the current it needs, quite a few diodes have reverse polarity voltage up to about 2 volts anything over that you even for a fraction of a second you will kill the diode, so make sure you have the right pin layout on the diode you can not just touch the pins and hope you get them round the right way have allok around this site you will find the information, you have to take your time and do a bit of research first otherwise it will end up costing you lots of money herea the link on you tube about my laser torches also there are lots of video clips on you tube about hoe to build such devices my video does not show the construction
    http://uk.youtube.com/watch?v=1dgelvEcqqc i hope the link works ok hope this helps Kaz also on you tube it says 650nm diodes they are not they are 660 nm
    Last edited by kaz; 11-20-2007 at 14:25. Reason: my spelling is crap and still is lol

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