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ArcticMyst Security by Avery

power supply laser burner

Joined
Feb 9, 2016
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hey guys can anyone suggest a good laser diode for my computer power supply burning laser project. it puts out about 6 volts. anything helps i don't know a lot about lasers.
 





Joined
Jul 10, 2015
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That's kind of like asking if anyone can suggest a sports car for my racing project using this can of 87 octane can of gas.

You have, to use an old phrase, put the cart before the horse.
 
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Feb 9, 2016
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sorry i didn't fit your criteria to answer my question. i was going to use a diode i pulled out of a dvd burner but it broke in the extraction process. i want to know what mw i need in order to make it a burning laser. using 87 octane can of gas
 
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Your question makes no sense the way you asked it. The diode needs a constant current driver. The driver needs a power supply. What driver you need depends on what diode you have. What power supply will work depends on what driver you are using. You can't power the diode directly from a power supply or it won't last long.

To answer your question about burning, lasers of less than 100mW can burn when properly focused, they can pop a balloon or light a match although not always quickly. If you want a burning laser you will be satisfied with that burns easily then you should look for something 500mW or more, this also depends on the wavelength too. For burning try 445/450nm and 405nm.

Alan
 

diachi

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You need to be more clear with what you want to achieve...

Modified a computer power supply in which way?

Really you can burn with 50-100mW, just not well. Ideally you want >100mW.
 
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It's not a matter of meeting my asking criteria and I am not trying to be rude, you really left a lot out of your inquire and there is not a simple answer to your question.

Even if I were to assume what you meant I still don't know the type or thickness of the material you want to burn, if you have a feed rate in mind or anything, so again it's not a simple answer.

Your power supply puts out about 6v but how much current?

If you can give more information there are people here who can point you in the right direction.

As most laser diodes will need a current regulating driver you may find it more convenient to use rechargeable batteries if your device is to be portable.

If you want to build a cnc type x/y axis burner cutter then you could incorporate your power supply but it will have to power a current limiting driver, or you will have to build a limiting circuit.

What ever your burning purpose be aware that any laser over 5mw requires eye protection, laser safety glasses that attenuate the wavelength that you are burning with.

There are burning lasers in hand held wands that will run on 3 to 24 volts with their own buck/boost limiting driver built in that are not expensive, but you must buy the safety glasses first.

Much can be found on ebay

But remember to buy laser safety glasses to protect your eyes before ever trying to burn with a laser, sun glasses will not work.
 
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Joined
Sep 12, 2007
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6V is a non-standard voltage for computers. What modification did you make?
 
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Feb 17, 2016
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i modified a compute power supply

Right, but what model power supply is it?

There are many companies who manufacture computer PSUs, and they can be rated for anywhere from 250 watts to 1000+ watts.

I'm not even sure why you'd want to use a salvaged PSU. Like RC said, rechargeable batteries would be a much easier and less duct-tapey power source.
 
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What is the project? What do you want to burn/cut? At what rate of travel/speed? Will it be going in a labby or mounted on a printer/cutter type machine?
That alone will drastically change parameters.
 
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Feb 9, 2016
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look guys I'm sorry i am just an amateur at all this laser stuff. 1. i built a constant current driver.
2. because the driver i built was supposed to be cheap not efficient a lot of the power going though it gets turned to heat that is why I'm using a power supply instead of batteries. i intend to continue doing laser projects if this one goes well.
3.the purpose of this project was to make a cool thing i could have on my work bench that i could make for free out of parts from a broken computer.
4. the power supply is a 350w model
5. what i did was i soldered together the black and green wires to keep the power supply on then i soldered the 12v yellow wire to the input of my lm317 chip then ran the output of that to the diode then the output of the diode to the 5v red wire thus getting about 6-7 volts when you consider the voltage loss of the lm317 and the fact that i used a slightly higher resister due to me not having the one i needed.
6. the model number is BP350
 
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really what i want help with is what diode can i buy to replace the one i was trying to extract from the dvd burner. Has to be under $15 because i don't think i it is worth spending more on a project like this.
 
Joined
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You're getting WAY ahead of yourself. You need to understand some basics before trying to power a laser diode, or it can end up being an expensive way to learn your lesson. Search the forum for test load. Test/dummy loads are a lot cheaper and a lot more tolerant to abuse than laser diodes.

i soldered the 12v yellow wire to the input of my lm317 chip then ran the output of that to the diode then the output of the diode to the 5v red wire

The 5V rail is not designed to sink current. It will become unstable and shut down. It will only work reliably if you have a large power resistor between 5V and GND. Something on the order of 2.2ohm 15watt.


...about 6-7 volts when you consider the voltage loss of the lm317

The minimum voltage dropout of the LM317 is closer to 3.5V. You cannot read the voltage of a current source with no load. It does not reflect how it will behave with a load. At all.

i used a slightly higher resister due to me not having the one i needed.

Resistors do not drop voltage with no load. How do you know what value you need without knowing which laser diode you'll be using? What value are you currently using, and where is it connected?
 




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