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ArcticMyst Security by Avery

Diode damage on homemade blu-ray?

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Nov 23, 2007
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Hi all, I recently put together my first blu ray pointer using one of daedal's GB diodes. Soldered together a driver circuit, and gave it all a nice handheld home. But I have a question. As you can see from the picture, theres a faint yellow glow around the dot. Has anyone else experienced this?

Could the laser diode be damaged somehow? Like from too much power to run it but not enough to burn it out? I was very careful to use only just enough power to get the diode to start lasing but I fear I screwed it up anyway.

Thanks everyone
 

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Doesn't appear to be a diode problem. If anything, your lens might be fluorescing.
 
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theres a faint yellow glow around the dot. Has anyone else experienced this?

I saw that when I first powered up my blue-ray, I know mine was underpowered for the circuit I was using. When I put rechargables in there was enough overhead voltage for the regulator to work properly and the yellow went away.

What voltage are you using into the LM317? For a blue-ray you need an absolute minimum of 7.5v, 9v has been found to be best.

Regards rog8811
 
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I'm using a brand new 9v so I know that's not a problem. I'm using daedal's circuit and I kept the trimmer pretty low because I'm afraid to turn it too high.

Maybe I'm being too cautious... I'm at about 45ohms of resistance right now(it started lasing a little bit above that), do you think its safe to go any lower?
 
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I couldn't get a good photo of my odd beam so I drew it, does yours look anything like the pici below?

Have you put a 1ohm resistor in series with the LD to see how many ma you are feeding it? (by measuring the voltage drop across the resistor in mv) The consensus around here is find lase point then go another 10ma.

If you do this make sure you short out the capacitor before connecting or disconnecting the LD.

Regards rog8811
 

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mrblack927 said:
I'm using a brand new 9v so I know that's not a problem. I'm using daedal's circuit and I kept the trimmer pretty low because I'm afraid to turn it too high.

Maybe I'm being too cautious... I'm at about 45ohms of resistance right now(it started lasing a little bit above that), do you think its safe to go any lower?

45 ohms is only gunna let ~28mA - pretty low for a blu-ray diode. Perhaps lower it to 32-35ohms
 

Gazoo

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He..he...I was just going to say that. I have been recommending 33 ohms which will supply 38ma's to the diode. I am using a multi-turn precision pot and have mine set to supply 38ma's. Radio Shack has 33 ohm resistors.
 
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Thanks everyone, I lowered the resistance it seems to work fine. I don't know if the 'artifacts' necessarily disappear, but they are now overshadowed by the actual laser dot, which is fine too.

appreciate the help! :)
 




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