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Thread: Pioneer 112 Results (red Hot)

  1. #1
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    Thumbs up Pioneer 112 Results (red Hot)

    Hi people, a couple of weeks back I decided to do a list of dvd burners that are good for getting the diode out and in what type of format closed can/open can and the dreaded fully open hunk of metal ( for want of better words) after looking around a few sites I came across a diode that appeared to be getting good reviews from a few people so I decided to see what all the fuss was about, the dvd burner in question was the pioneer 112 this was nearly two weeks ago, two days later the two units I bought arrived costing around £46 for the pair. Having spent two weeks tomorrow testing them I am very pleased with them, I initially bought two one for keeping and the other to test to destruction but after 2weeks of well over the top running conditions I did not have the balls to kill the little guy and he is still running as good as the first day he started spitting out coherent light, if I damaged the diode or not is a different matter but at the moment there is know visible signs of degrading whatsoever.
    This is what I done with the diode, after getting the main optical block of off the the guide rails inside the burner case (this was easy just a few screws to undo)as in picture 2 this is with the cover taken off.
    The removal of the diode was pretty much straight forward leaving the diode in a heavy for its size heat block as in picture 3
    I clamped the heat block in the vice and made a small cut on the thickest part of the heat block ( be careful not to go to deep ) then got two pairs of grips and carefully broke the heat block leaving just the diodes the heat block almost felt like lead it certainly cut like lead with my junior hacksaw (im guessing here) cut it like picture 4
    At the end of it you should be left with a diode or diodes like this in picture 5
    After wiring it up and covering the wires with small heat shrink tubing I inserted the diode into a piece of 12mm aluminium bar that I had already machined with the correct counter bore(5.6mm) as in picture 6
    Picture 7 shows the diode mounted on the 12mm aluminium bar with thermal epoxy resin on the top and behind the diode this stuff excels in thermal dissipation and it goes off rock hard just make sure your happy with the position before this stuff goes off as you never be able to move it once it has dried off which depending on the heat in the area can be 5 minutes to 15 minutes totally rock hard after a few hours
    Picture 8 shows the 12mm round bar inserted into the main heat sink block which I had machined earlier on in the day the optic part most of you will recognise as the axim laser module I only use the front optic part, the 12mm bar and the optics are held in place by 3mm grub screws they are a bit long but I ran out of the shorter type the brightness of the laser has over saturated the red that’s why it looks more white than red, also the 12mm bar has a normal thermal compound on it to suck the heat into the main block
    The test, which is still ongoing, is a long term stability test which started almost 1.5 weeks ago normally with a 16x/18x or 20x diode I would see what other people are cranking there’s up to and keep mine around about the same all depending if you want high power for a shorter diode life and visa versa but after reading a couple of reviews I decided that the diode that I thought I was going to test to destruction was going to get high power from the off so I cranked it up to 180mw for the first couple of days just checking the power from time to time and beam shape all looked well so the next couple of days it went up to 200mw where it sat for 3 days this is the nice part I then took the poor little thing up to 250mw where it still sits today from 180mw the main block was 2 degrees over room temperature at 250mw it is 7 degrees above room temperature( 21 degrees room temp ) 28 degrees in total the most striking differnce between this laser diode and others that I have used is the size of the laser chip itself measuring approximately 30% longer than other chips I have seen there could be lots of reasons why this is the most common is laser gain and dopent levels either way it makes one hell of a diode you can see the difference in size on picture 9 the diode on the right is a Lite-On LH-20A1p 20x burner the pic on the left is the PIONEER 112 you can clearly see the difference in length.
    To get 250mw I am using one of Robin’s driver boards ( great bits of kit) at 3 volts at 339 milliamps now I am thinking of combing two for half a watt of red, I don’t know how much longer it can take this sort of punishment bUt rest assured when it goes to diode heaven you guys will be the first to know but in the mean time I shall just have to put up with the wife moaning about turning it off
    All the best Paul.


















    just a caution try this in a axim module and you will probably fry the diode in 20 minutes.
    Last edited by kaz; 01-17-2008 at 10:30. Reason: added something

  2. #2
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    Nice!

    You soldered the diode to the mount? That is one step that could have gone horribly wrong (especially with an open case like that). Have you measured the beam diameter at the aperture? I built my first red laser from a DVD burner diode yesterday using one of those Sony 16x diodes and was surprised to find the beam so wide.

    Gotta be careful with these beams though. They will not only hurt your eyes but also your skin. The latter I found out by placing my hand in the focal point of the beam (@150mW) and soon discovered that it had actually made a small hole in my hand, about 1 mm deep. Wouldn't want that to happen to my eye!

    Did you find any useful optics in it?

  3. #3
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    Hi Tocket, if you read it it carefully it says that i mounted the diode with thermal epoxy resin its not solder i gave up trying to squash diodes into the mount a while back beam diameter at the optic exit is about 4 mm the size of the beam is dependent on what optics you are using (focal length) i ware saftey glasses as much as possible always be carfull when using lasers over 5mw its only a matter of time before your luck runs out if you dont have protective glasses do everything possible to avoid stray reflections and if you are setting your laser up if you can turn the power down untill your happy with your setup then turn it up lasers are fun to different people and for different reasons but as soon as you get complacent with them your asking for trouble the only thing that was of any use in the optics train was the cube but thats to small for anything pratical.
    Paul

  4. #4
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    Very nice report, I like the looks of those blocks a lot. Hopefully this will last a long time for you. Can you plot the current verses power output plot up to your operating point? What was its threshold current?

  5. #5
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    Oh, I see now... Sorry. It looked just like solder with that shiny surface. Still, would not be nice to have some thermal epoxy in your diode.

    I opened a really old pioneer DVD-reader and found a pretty large dichroic mirror that reflects red really good, but unfortunately it gives about a 50/50 split at 532 nm, so it can't be used to combine red and green.

  6. #6
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    one diode was around 60ma the other one i was testing hard was around 65ma when i get some more hobby time ill do just that should have done it from the start

  7. #7
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    Talking its still going

    Well its still running its been on test now for almost 3 weeks at 250mw, the diode has surpassed all my expectations I took the laser module up the garden to my workshop 5 days ago where it is still running as I write this, the wife one on this as she got feed up with it being on (she doesn’t understand what its all about bless her) anyway
    With the weather being only a couple of degrees above freezing in most parts of the uk the power output that was sitting around 250mw went up to 260mw in the cold conditions in my workshop then during the day as it warms up a bit it drops down to around 253mw at 14 degrees at room temp indoors I had it stabilised at 250mw the other module I fitted in a case with safety key turn on and off this one has only done a couple of hours and iv turned it down to 220mw for a longer working life the beam specs are not to bad either 4.5-4.8 mm at 25 mm from optics and 20mm at 65 feet , if any of you guys are interested I could make up a aluminium module like the pics show in the first post for £72 with diode mounted if you want a driver for it will be another £25 its one of Robins driver boards which can be modulated depending if Robin can make more driver boards for me but if you have your own driver I don’t think it’s a bad price. I have put a few pics in of the cased module this one is non-modulating. Power on red led/ green led is key power on/ and ultraviolet showing as blue is laser on off if any one wants it make me an offer there is no warning labels on the device and will be sold as oem that’s if any one wants it lol.
    All the best Paul





  8. #8
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    Cool Kaz!

    Do you know the wavelength of the diode?
    This can be measured with a difraction grating like the ones found in CD / DVD players.
    If interested I'll look up the paper that describes this.

    cheers Z

  9. #9
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    zoof
    that paper would be cool - I have tried to do this myself in the past. I used he-ne dpss green and argon 488 for reference and though I could get a decent separation of the beams I could never get useful or conclusive results.

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
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  10. #10
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    Rob, I'll look up the paper tonight and see if I can make a quick practical guide.
    I used 473 to calculate the difraction grating's linewidth and checked and then measured the HeNe's wavelength within 2nm. That was pretty accurate and I feel that with a better setup it could have been within 1 nm.
    I needed to check whether my new red diode was indeed 645nm as claimed by the seller - it was closer to 650nm as expected.

    Z.

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