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FrozenGate by Avery

DIY Homemade laser diode driver

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Hey Guys I have a Problem
I just took apart the Aixiz module so I have the front part with the weak diode in it and the circuit board attached to it, but I can't get that apart. I can't either push out the diode, nor get the circuit board off the diode ( i tried unsoldering) it just like it's hardglued in there or something... I'm also really afraid to break it!
How should I proceed?
 
Use a hammer and a screw driver on the diode. :P

You can also get a vice and do this:

remove_diode1.jpg
 
No body wants a 5mW LD so you might as well murder it in order to get it out of the housing. ;D
 
eventually, ill get around to usign this when i understand all this stuff a bit more haha
 
you can use a 5mw diode to maybe practice your soldering, or try removing the outer can safely
 
Correct, the housing acts as a heatsink and the lens focuses the light coming from the laser diode into a laser beam.
 
I've just read your tutorial and I must say, good work. This is exactly what I've been looking for. Sorry if my questions are repetitive in comparison to the rest of the posts, but noting that there are 63 pages of posts, I didn't like the idea of reading each one for my answer.

First off I want to make sure that I've got all the components correct. I live in Australia so I'll be buying from Jay Car electronics:
Capacitor - hxxps://secure.vividcluster.crox.net.au/jaycar2005/productView.asp?SUBCATID=859&CATID=51&ID=RE6332&URL=index
Voltage Regulator - hxxps://secure.vividcluster.crox.net.au/jaycar2005/productView.asp?SUBCATID=320&CATID=33&ID=ZV1615&URL=index
Diode - hxxps://secure.vividcluster.crox.net.au/jaycar2005/productView.asp?SUBCATID=388&CATID=33&ID=ZR1004&URL=index
Laser Diode - hxxps://secure.vividcluster.crox.net.au/jaycar2005/productView.asp?SUBCATID=270&CATID=33&ID=ZD1954&URL=index

I couldn't find a suitable 4/5ohm resistor so I figure that I can just rock up to some electronics store (I know a few) and ask around for one. I realise that I haven't included a pot in the list. This is because there are specs included with the LD that I'm buying and I figured I could get the exact resistor that I needed instead of accidentally changing the resistance and blowing the diode.

SPECIFICATIONS
Threshold Current: 30mA
Operating Voltage: 2.3V
Operating Current: 45mA
Optical Power: 10mW
LD Reverse Voltage: 2V
PD Reverse Voltage: 10V
Size: TO-18 (5.6mm dia)

Am I correct in my assumption that to get the desired resistor, I take the operating current (45mA) and divide it by 1.25, giving me a 36ohm resistor?

I think that's everything. I'll post my results after I construct the laser.
 
Unless you're buying a lot at a time, just buy one of the kits from Senkat's store. They're all designed basically the same.
 
rog8811 said:
@Daedal, Thankyou for doing that...I have just ordered some regulators.

When it comes to other components I assume that a 200ohm pot would suffice? Will any signal diode do, I have a shed load of 1N4148's.

This next question will really show my ignorance.....But, if this circuit were to be tested on a standard led (rather than the precious laser diode) would the charecteristics, IE current draw, be anywhere near similar?

Regards rog8811

*Hope the mods stick this in the sticky area with sticky stuff...I will be stuck when it falls down the page ;)*

*edit....years after posting this, and having built dozens of these circuits.. easy to follow picture follows ;)


awesome, this is the clearest pic of all :)



what would be the blu-ray's numbers?




EDIT: d*mn!!! almost 80 pages!!
 
Well, for a bluray you pretty much leave the circuit the way it is, you only have to change the limiting resistor.
Use a 50 ohm pot, (100 ohm should work fine too) and use a resistor to limit the current going to the diode. The current depends on the diode you're using.
 
Daedal said:
Thank you all for motivating me to make a guide like this one. I hope this answers any questions and clears any confusions. If anyone requires any further support please do not hesitate to ask questions. :)
...
Required components:
 Component   DigiKey RadioShack Approximate Price
  Capacitor     1 2 1    ~ $1    
LM317     1 2 1    ~ $2    
Potentiometer 1 1    ~ $1    
   Resistors     1 1 Pennies
Silicon Diodes 1 1 Pennies

As far as I've understood, the driver needs the LM317 and the potentiometer to adjust current, the capacitor to avoid voltage spikes.
But what's the silicon diode for?
 
That's for polarity protection, so you don't kill anything in case you put the batteries backwards.
 
Quick question, its probably been answered but I don't want to read all 79 pages to find it. :o

Say I wanted to drive a LD at 100ma. With three AAA batteries in series, I have a voltage source of 4.5 volts. The batteries are connected in parallel with a capacitor, as well as the LD assembly. The LD assembly consists of the LD in series with a 45 ohm resistor. Assume the LD has no resistance for the moment.

When I connect the batteries the capacitor will suck up any voltage spike and become an open circuit. From there the current would run through the resistor and LD and back to the batteries. The 45 Ohm resistor would limit the current from the 4.5 volt batteries to 100ma. Assuming I don't ever connect the batteries backwards, I can't really see any problems with this setup. Obviously the LD would have some resistance to it, but I was thinking I could just use the 45 ohm to start and slowly work my way down until I get 100ma going through the LD. I have several hundred resistors of assorted values and I know the math to combine them to get various resistances.

Is there some fundamental flaw in this design? Because I don't really see one and it seems to be alot more simple (once the right resistance is found) then the whole current regulation circuit.
 
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