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AggieTX

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Hi, just joined and I'm new to lasers. I couldn't find the answers to a few questions, but m sure they have to have been asked before. Any help would be appreciated.

I read a lot of easy projects and watched some videos on YouTube about making a basic laser pointer that could do simple stuff like cut through tape and light matches. A lot of them seemed to be able to do this with the diode from a pc DVD burner drive.'I had an old one sitting around and figured "what the hell".

I ordered the little aixiz module and removed the diode. I carefully extracted the diode from the drive and installed it in the module. I hooked it up direct to A cr123 3v battery(I now know this is not good). The laser worked, but did not seem to be any more powerful than the weak laser pointer. I then soldered on the driver that came with the module. Same thing, weak and no burning.

Instead of looking into this more; I figured I needed more power to the diode, so I bought the 445nm driver from aixiz that says it can do 405-445nm at 300-1000mW. I hooked this up to the diode and got the same thing.

I then read something that referenced multiple diodes being in a drive. I found another diode hiding in what Im assuming is thermal grease. I carefully hooked it up to the driver and same thing.

I got frustrated and bought a diode online that won't come in for 2-4 weeks becUse it shipped from hong kong. It is a 100mW blue diode (405 or 445nm) I forgot which.

Someone please tell this idiot newbie what he is doing wrong...

Can the red diode burn with whT I have? How do I tell which is the "burner" diode? Will the diode I'm waiting on work and will my driver be too much for it?

Thanks,
The Idiot
 

Fenzir

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You might have overpowered one of the LD's and burnt it out, what we call "LEDing", where it will then emit a dim light. If you have a link to the machine you are referring to, we have probably heard of it before and would be able to provide some information. The diode you bought is probably a 100mw 405nm diode. These are not too visible seeing as the wavelength 405 is not precieved by humans that well, but it sure can burn and damage eye sight if not used properly. 100mw of 405 will pop baloons, light matches and you can see the beam dimly at night. I'm not an expert. And with the driver you bought, is the current adjustable? If so, you might be able to set the current higher and therefore make the laser more powerful. However, the most important thing to do right now is, if possible, find a link to the machine you extracted the diodes from and listen to others.
I'm not 100% sure, but are pc DVD burners 650nm or IR?
 

qumefox

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First.. changing the driver doesn't change the wavelength of the diode. Using a driver made to run a 445nm diode at 1W won't make a 250mW 660nm diode put out 1W at 445nm.

Most likely what you've done is you've 'LED'd your diode (i.e. Exceeded the optical power the die facets can handle and burned them off.. thus turning your laser diode into a LED) when you tried to direct drive it off the battery.

DVD burners will have two diodes in them. One is 660nm (red, for DVD) and the other is 780nm (NIR, for CD's). You also have to make sure it's a BURNER and not just a reader. Readers will only have low power diodes. Generally, the faster the burner, the higher power the diode, though 660nm diodes don't get much above 300mW.
 

Morgan

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The beginnings of a laser enthusiast can be humbling and frustrating can't they? Don't worry it happens to us all.

Have a look at the link in my sig and that may help.

To the diagnosis of your observations, there are a few things here...

Firstly, when you hooked the first diode up direct to 3V you probably blew it, (I do assume here that you did actually find the red LD and not the IR but I can't be sure of course). Reds in drives like this will almost certainly only require around 2-2.5V.

Secondly, when you hooked up the driver, the diode, (now what we would call a 'zombie'), will get enough current to give as much light as a LED but would not likely lase even if it was healthy. Having said this, the outcome would depend on the type of driver you purchased. This should be explained in the link in my sig. See Linear as opposed to Buck/Boost.

Thirdly, when you found the other LD, it would have been the IR diode, (still assuming you found the red one first). This could be dangerous as now you have installed the driver and possibly have a laser diode working well but at a wavelength your eyes see as very dim. DO NOT BE FOOLED! This laser could well be very powerful and damaging to your eyes so best leave it alone for the moment if you have no goggles. To see it more clearly try viewing it through your mobile phone camera. If it is indeed the IR diode, and it is working well, you will certainly see just how bright it really is when viewed this way.

Fourthly, if you have a Linear type driver, one CR123 will not run a 100mW blue, (I would suggest this to be a PHR-803T diode that is 405nm and is violet not blue but that is a guess purely made on your 100mW description). This is because a Linear driver can only supply a voltage output close to or below the the input voltage, (3V in this case) and a Bluray diode requires around 4.5V+. You need a boost driver for a single CR123 or you need more batteries in series to bring the overall voltage to 4.5V plus whatever the driver requires, (usually something about 2.5V at worst). Anything above this total, (7V), will be turned into heat at the driver so be sensible about your choices. And before you ask, no, the square 9V batteries are not a good choice as they empty quickly and are expensive!

[EDIT: Qumefox makes a good point about a 405-445nm driver not changing the wavelength but I think you were just looking at the output power here, correct? The 405 and 445nm diodes have different characteristics to reds and others so it is not wise to use drivers for other colours as you don't know how they will react. For example, a 405 or 445nm driver outputting 300mA may well blow a red diode capable of that current.]

Fifthly, telling which diodes you have and where they are depends on the drive they came out of. You could try punching the serial number of the drive into the search box above these posts and see if anyone has posted any data. Good red diodes are available from many around here for less than $10 in most cases though, as are bluray diodes. Common red ones we all use are the LPC-815, (aka the LOC or Long Open Can).

I hope that is a start and you have plenty more to research. Good luck and welcome to LPF. The real hobby starts here!

M
:)
 
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AggieTX

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Thanks for all the help so far. You guys are awesome! I posted the links to the items I purchased so you know exactly what I have.

From the replies, it looks like o should have one red diode and one IR diode from the drive. I double checked and it is I'm fact a DVD RW drive, but both diodes I got out gave off red light. Even if I LED'd the diode, I'm guessing the IR diode should still not give off red light. Both diodes gave off a focusable beam, but neither appeared to be very powerful. Could there be another diode hiding in the carriage?

Will the diode I purchased work with the driver? What type of power will I need to feed it so I dont ruin the diode? I do have a rechargable flashlight battery for a streamlight stinger that says it's 3.6 or 3.7 volts. Can I use that?

Thanks for the help.
 

Morgan

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The module should just need 3.2V applying and you're good to go. It will have a driver fitted but at 35mA draw will not drive a burning diode unless it has a LOT of adjustment, and that's unlikely I'm afraid. It can be used to house a different diode however but you'll need some tooling or some initiative to swap out the components. Both are things you will need if you wish to continue building lasers.

The driver looks to be a boost driver but the details and pictures are not really good enough to guarantee that.

[EDIT: The link for it said it was an Aixiz driver so here is the link to what seems to be the same one - http://www.aixiz.com/store/product_...d/108/osCsid/c2d8dafd1f5eaab5671f0e8ee4d64784

It would not appear suitable to drive your 100mW diode, without modification, as I think the current output would be too great. It claims it's suitable for 200mW diodes so will probably just pop yours. You need to either invest in a different driver, diode or build your own driver for a few bucks. I would go with building your own as it's cheap, reliable and you learn whilst you do it. You will also need a Dummy Test Load. Details of these and their use can also be found in the link in my sig. The 3.7V battery can be used but you need to consider your whole setup to know if it will be correct.]

The diode is almost certainly reporting to be a PHR-803T Bluray capable of about 100mW but this is not certain as I don't know the seller. Better to buy from a reputable seller here to be frank.

[EDIT2: IR diodes do appear to some as dim red. They are more accurately described as Near InfraRed or NIR, (as Qumefox stated). The dim red glow is deceiving and many times more powerful than it looks. Definitely use your mobile phone camera or other digital camera to prove this to yourself. Apart from anything else - it's interesting!]

M
:)
 
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Remember Lasers are dangerous. Even a short burst of laser light could give you a blind spot or blind you all together. Before you get too far in to this hobby remember safety. So BEFORE you build your laser get safety goggles for the appropriate wavelength (trust me if you wait until after you finish your laser you will be tempted to use it with no eye protection at all and you don't want to damage your eyes). Make sure you buy a good pair of goggles not just some cheap-o piece of plastic. I would suggest these, they are proven to be good by several members of this forum and they are fairly cheap.
Laser Glasses - UV to Green Lasers Protection 190-548nm :: Laser Safety :: Dragon Lasers
 

AggieTX

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Those glasses are definitely in my price range, but shipping is as much as the glasses almost...

Any other suggestions for getting some glasses in TX?

Thanks.
 

AggieTX

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Anybody got plans for a driver that will work for my diode that can be run by a 3.7v lithium ion batt?

Diode specs show 405nm, 5v input voltage, max current at 185mW, but shows as a 100mW diode. I'm fairly competent at building circuits, just not good at designing them or calculating what values are needed in the components.

I've also been having fun taking apart some old electronics that I needed to toss anyway. Nothing with any powerful diodes, but still fun. My old DVD player had a 4 prong diode and an old laser level had a busted case, but a free module and adjustable culminating lense.

Thanks guys
 

qumefox

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Your probably better off buying a microboost from drlava. Boost drivers are fairly complex even with schematics, and buying the needed parts in small quantities can easily exceed what you can just buy one for.

Unless your already dead set on a particular host, your best bet is probably using two li-ions and a linear driver.
 
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