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ArcticMyst Security by Avery

DIY Homemade laser diode driver

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Skram0

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Ok, got my GB LD yesterday. :cool: Popped it in my Aixiz module with a little thermal paste around the base of it. I have it tuned to about 160mA using a DMM in-line before it hits the LD. I measured the voltage on the LD to 2.5v.

I stacked a 2nd 10 Ohm resistor on top of my original 10 Ohm (now parallel) to make 5 Ohms since I didn't want to be limited to my original design of only 125mA max. But I measure the resistance, looking at the schematic, from the top of the diode to the out of the voltage regulator and measure 8.6 Ohms. So with all this information, how do I calculate how many Watts I'm running my GB LD at? Some calculators I end up with about 0.2 Watts, and others I get 0.4 Watts. You think around 200mW sounds the closest?

Here's a pic of my GB laser next to a key chain laser. Guess which is which!! ;D
 

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Skram0

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Here's a pic of my finished, for now, project.
 

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Things

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hmmm is the GB diode is the scattered dot? :D man that's a pretty well focused 1mw!no scatter! nice work!
 

Skram0

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The GB dot looks really focused when I shine it on a piece of black rubber-foam thing. Turns into a spec as the foam smokes and melts instantly.
 

Skram0

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So any answers to what mW I'm cookin at with the above results? Or did I distract everyone with the pretty pictures. ;D
 

naplam

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Skram0 said:
and measure 8.6 Ohms. So with all this information, how do I calculate how many Watts I'm running my GB LD at?
That's an important point about the resistance: first make sure you measure 10% or 20% tolerance resistors because that can be a significant variation in current in this particular application. And second, most potentiometers have like 2 ohm resistance minimum, and that adds up too. So don't take for granted resistors are exactly what they say and potentiometers are 0 to whatever ohms.

The output power depends on temperature and current. Use the graph in the diode datasheet.
 
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:-? I dont understand why some people make it hard on theirself using different resistors. Just buy one 5 ohm resistor and place it in the circuit. DDL said that is the best way to get the best out of the LD. Or am i missing something  :-?
 
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Skram0 said:
So any answers to what mW I'm cookin at with the above results? Or did I distract everyone with the pretty pictures.  ;D

Well, DDL answered that question somewhere else. If you use 5 ohm resistance and everything the same as in the scematic, you will have about >150 mw. I dont know if he tested it with a laser test device.
 
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