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[SOLVED] DvdRW laser diode not burning?

viliuks

viliuks

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So I made a driver circuit, made it output the max output for the laser diode, but even when focused it doesn't burn. I thought It was the diode from just a simble dvd/cd rom. But no, It was from a DVDRW rom. So whats the problem? And If anyone knows where I could buy some diodes and send them to Lithuania, please post a link :)
 
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Re: DvdRW laser diode not burning?

What is the "driver circuit" that you made?

What are you using to power it? What's the schematic of the driver? What's the desired output current? Do you have a multimeter, have you tried using a test load on the driver first?

How is the diode extracted? What module are you using? Can you post any pictures of your build? What do you mean it "doesn't burn"? Is the diode's output bright or very weak?

Please, for God's sake provide more information than "it doesn't burn". How else are we supposed to help you?

If you want to buy diodes, I recommend DTR's shop:
https://sites.google.com/site/dtrlpf/home/diodes
 
Re: DvdRW laser diode not burning?

Eudaimonium said:
What is the "driver circuit" that you made?

What are you using to power it? What's the schematic of the driver? What's the desired output current? Do you have a multimeter, have you tried using a test load on the driver first?

How is the diode extracted? What module are you using? Can you post any pictures of your build? What do you mean it "doesn't burn"? Is the diode's output bright or very weak?

Please, for God's sake provide more information than "it doesn't burn". How else are we supposed to help you?

If you want to buy diodes, I recommend DTR's shop:
https://sites.google.com/site/dtrlpf/home/diodes
Click to expand...

I'm sorry for the lack of information. Well my driver is lm317t circuit, with 3.3ohm resistor + 100ohm pot. Diode is extracted from a dvdrw rom. Desired output 300mw. And it outputs 300mw. I'm powering the driver with a 12v wall adapter. Diode is glowing very bright.


Circuit schematic:
FRI2FF7GQRB6REO.LARGE.jpg

D1- 1n4007 diode
R1 - 3x 10ohm parallel resistors
r2 - 100ohm pot.
D2- Laser diode

Crappy phone pictures. (too big for forum, added direct links)
http://i.imgur.com/h9fMV4Y.jpg
http://i.imgur.com/rOmz4E7.jpg
 
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Re: { UPDATED }DvdRW laser diode not burning?

Please use this simplified schematic for LM317 or LM1117 driver in the future:


If you reduced your potentiometer to 0 ohms, resulting in 3.3 ohms total resistance, your total current should be, by Ohms law:
1.25 Amperes / 3.3 Ohms = 0.378 Amperes of current.

Normal Long can diode should be able to handle that kind of current, producing around 200mW of output.

Short can diodes can only take around 150mA - 200mA of current and produce around 100mW of output.

Can you please post a picture of your diode?
 
Re: { UPDATED }DvdRW laser diode not burning?

Eudaimonium said:
Please use this simplified schematic for LM317 or LM1117 driver in the future:


If you reduced your potentiometer to 0 ohms, resulting in 3.3 ohms total resistance, your total current should be, by Ohms law:
1.25 Amperes / 3.3 Ohms = 0.378 Amperes of current.

Normal Long can diode should be able to handle that kind of current, producing around 200mW of output.

Short can diodes can only take around 150mA - 200mA of current and produce around 100mW of output.

Can you please post a picture of your diode?
Click to expand...
Ofcourse, I will post pics tommorow, because I need to charge my dslr
One thing tho, When I lower the potentiometer more than 11ohms the diode starts to fade. Not really sure what happens.

By the way, what resistance should I use to drive this https://sites.google.com/site/dtrlpf/home/diodes/oclaro-700mw-638nm-diodes
at 700mw. If I'm not wrong it should be 2.2 ohms on resistors right?

:thanks:
 
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Re: { UPDATED }DvdRW laser diode not burning?

Eudaimonium said:
2.2 Ohms is 550mA of output, which is somewhat "conservative" for an Oclaro diode. I recommend 800mA via this driver:
18V 5W Circuit Board w/ Cree for Flashlights (16.8mm*5.5mm) - Free Shipping - DealExtreme


What diode are you driving currently? Can we have a picture of diode alone? If it is a short can diode, it's probably blown out and explains why are you seeing the low output power.
Click to expand...

What do you mean "short diode" ? If in size its not tall at all. And the diode was ripped out from a DVDRW so basic diode size I think.
As stated before, I will post pics tommorow, sorry :( And in reality I don't really know how to calculate the resistance I need for a wanted amperage, and I don't know how to calculate watts from amps, I'm a bit new to this. I know some basic stuff how to solder and read schematics. Not really calculating things
 
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Re: { UPDATED }DvdRW laser diode not burning?

Well basically DVD burner diodes can be of two types, short and long die.

Short die diodes only come in short can package. Like I stated before, these only output around 100mW max.

Long die diodes can come in long can, or open can package. These are the ones you want if you are building a red laser.

Oclaro 635nm diodes are much different than that - different color (wavelength), operating voltage, and beam characteristics. Basically they don't produce a nice dot the way DVD diodes do.

In that schematic, just plug in the current you need.

For example you want 800mA? That would be;
Resistance = 1.25 Volts / 0.8 Amperes

Resistance = 1.56 Ohms

This also works the other way around;
Current = 1.25 Volts / 2.2 ohms

Current = 0.56 A, 560 mA

I hope that's clearer a bit :) Waiting on pics of the setup, so we can get a stab at figuring out why your diode isn't outputting much power. My current guess is that you have overdriven it at some point, and if it was a short can diode, it couldn't handle the current and it went LED... hmm but you are saying that the diode is very bright, just doesn't burn anything.

It's also possible you're actually underdriving it. I would suggest replacing all the resistors in your setup with something as close to 6 ohms you can get. This will give you around 200mA current of output. At this current, both short and long can diodes should output around 100mW of power and be able to damage things :D
 
Re: { UPDATED }DvdRW laser diode not burning?

Eudaimonium said:
Well basically DVD burner diodes can be of two types, short and long die.

Short die diodes only come in short can package. Like I stated before, these only output around 100mW max.

Long die diodes can come in long can, or open can package. These are the ones you want if you are building a red laser.

Oclaro 635nm diodes are much different than that - different color (wavelength), operating voltage, and beam characteristics. Basically they don't produce a nice dot the way DVD diodes do.

In that schematic, just plug in the current you need.

For example you want 800mA? That would be;
Resistance = 1.25 Volts / 0.8 Amperes

Resistance = 1.56 Ohms

This also works the other way around;
Current = 1.25 Volts / 2.2 ohms

Current = 0.56 A, 560 mA

I hope that's clearer a bit :) Waiting on pics of the setup, so we can get a stab at figuring out why your diode isn't outputting much power. My current guess is that you have overdriven it at some point, and if it was a short can diode, it couldn't handle the current and it went LED... hmm but you are saying that the diode is very bright, just doesn't burn anything.

It's also possible you're actually underdriving it. I would suggest replacing all the resistors in your setup with something as close to 6 ohms you can get. This will give you around 200mA current of output. At this current, both short and long can diodes should output around 100mW of power and be able to damage things :D
Click to expand...
Alright!. By the way how do you convert 200mA to 100mw? And pics coming soon.
 
Re: { UPDATED }DvdRW laser diode not burning?

viliuks said:
Alright!. By the way how do you convert 200mA to 100mw? And pics coming soon.
Click to expand...

You don't.

You only need to worry about outputting a correct current from the driver into the diode. The driver automatically adjusts output voltage as needed by the diode.
 
Re: { UPDATED }DvdRW laser diode not burning?

Hang on, if this was a DVD ROM wouldnt it be a low power (5mW) diode rather than a DVD RW ?
 
Re: { UPDATED }DvdRW laser diode not burning?

SyKo said:
Well, i need to sleep more often.
Click to expand...
Indeed you should. :na:
Eudaimonium said:
You don't.

You only need to worry about outputting a correct current from the driver into the diode. The driver automatically adjusts output voltage as needed by the diode.
Click to expand...

I understand that, but if I want to know mw so how do I get it from ma?:thinking:
 
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Re: { UPDATED }DvdRW laser diode not burning?

viliuks said:
I understand that, but if I want to know mw so how do I get it from ma?:thinking:
Click to expand...

You don't get mW from mA. If you want to know the diode's power, you have to measure the output using a laser power meter. You can't calculate it.
 
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