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ArcticMyst Security by Avery

Broken green

Joined
Apr 12, 2008
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so I bought a cheap green of ebay. And no big supprise that it broke.

Questions.
Is there a reason i couldn't get it to run off of a power supply besides batteries.

How can i hook up the IR diode independently to test it?
I tried just regulated supply and resistors?

If my IR diode is dead can I just get a new more powerful one and used the same crystals to make a more powerful green pointer?

Thanks,
Micah
 





Joined
Jun 13, 2007
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1. What voltage were you running it at?
2. To test the IR diode just hook up a driver to the diode and power it up. Use a digital camera or webcam to see if any invisible light is coming out.
3. You can't just stick a bigger IR diode in there because ebay lasers have too small of crystals to be able to put out much more green with more IR put in to them because they get saturated.
 
Joined
Feb 25, 2008
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I can't think of any other way to test the IR other than removing the IR diode and hooking it up to another driver. You might be able to replace it if it is dead. Going with a more powerful one might not make more green since the crystal can only take so much IR. Adding too much IR can make it worse.

You might be better off buying a new pointer from somewhere else. The pointer you have now might not even have an IR filter.
 

JLSE

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You might want to try a new driver first. If it was a failure on its part , taking apart the diode and crystals will only add to the challenge.
 

Razako

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Just buy a new True 30 from Dx for $25. It will probably be a lot better than the ebayser ever was and you will save a lot of time and money.
 
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Apr 12, 2008
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Yeah i know it doesn't have an IR filter. It was under $12. I know i was being cheap so i wasn't expecting much.

is there any reason i cannot just hook the IR diode straight to supply with resistors regulating current?

Oh, and i have it in pieces so i am prepared to do whatever.

Thanks for all the good suggestions.

Micah
 

IgorT

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Oct 24, 2007
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Yes, there is a reason why you wouldn't want to hook up a diode to a voltage source through some resistors. Resistors don't regulate the current, but just limit it. And it still depends on the source voltage. It would take A LOT of tweaking to determine the correct resistors, which would limit the current enough, that it would still be below what it is capable of.

For laser diodes you need current regulation, and then you need to know what current the diode needs. If you hook it up to a voltage source, you have no idea what the current will be. With a current regulated driver, you can set the current to whatever you want, and it will stay there, regardless of what voltage you put into the driver.

Also, when diodes heat up, they lose resistance, so more current will flow through them, which can kill them, even if you limited the current with resistors enough for the diode to be safe when cold. I lost many diodes by hooking up to a power supply, even tho my PSU can regulate the current.


You should have just measured the current before you took it appart. You could still solder it back to the driver, and try it with batteries first, while measuring the current. If it is not drawing any current, the diode is probably dead.
But are you sure you want to power up an invisible laser diode which could have as much as 200mW or maybe even more? You don't even want to look at the (invisible) reflection of that!

And even if you verify it is still lasing, you will probably not be able to realign it with the crystals. Once you separate the diode from the crystals, the fun is almost always over. I managed to get only half the original power, after many, MANY hours of careful and patient aligning with special tools i had to make for it, so that i could adjust the position and rotation of the crystals with the laser pointed away from me.


If you want a green laser that works, go with DealExtreme, like Razako recommended. They are good for lower power greens, and very cheap at that. It won't be $12, but it will work. And they have free shipping.



Trying to repair cheap green lasers is never worth it. Just a new pump diode of the same power would cost more. And it probably wouldn't be in the same shape so it wouldn't fit. And if it would fit, there is no guarantee it would even make the crystals put out some green. If you just take a working diode out of a working laser, and put it back in into the same position, there is no guarantee it would still work. The tiniest difference in alignment can reduce the output, sometimes even to zero. The only reason for trying to repair one would be if you wanted to learn how they work, and to learn if you have the patience.. ;)

If you never built a red laser before, go with that first, and just buy a new green. And you can't hook up red diodes to a voltage source either! Look up drivers in the Experimenst & Modifications section.
 
Joined
Feb 19, 2008
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Neg the seller if it broke as well. As thats bad enough being sold a crap laser but it breaking? Thats icing on the cake.
 




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