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FrozenGate by Avery

Open can laser won't lase

R

rajkosto

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May 8, 2009
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I created a DDL circuit, and then harvested a laser from a pioneer 112D
ive seen everywhere that this is probably the best laser diode to use...and that it can take huge amounts of current etc

well, the only thing ive gotten out of mine is scattered red light (like a LED, even weaker)

it never gets to lase, and ive nver connected it to anything other than my ddl circuit (which can output from 12mA to 400mA on 1.7-2.2V)

ive gone to 200mA, and still no lasing, just the red light gets kinda brighter, and the casing begins to become very hot to even touch (never tested more than 20 seconds or so tho, so i assume no heat damage from this)

i assume that the laser will come out from the tip of the PN junction on the diode ? the thing that points outwards ?

here is a pic of it just being a led...

http://i42.tinypic.com/2uhab91.jpg
(its much brighter, the flash made only the brightest part red in the photo)
http://i44.tinypic.com/ou5oc2.jpg

the light seems to be coming from the middle of the PN junction

the drive this came from was broken...BUT it could still read DVDs if you angled it over the right way
 





thats what its hooked upto, a wall adapter, set at 9V
what im saying is that the OUTPUT (when i measure the legs of the diode), is 1.7-2.2v based on the current
 
i put it in the shell of an cheap chinese laser...in there it has a range of like 5cm, and is weak as hell, not a laser at all, because the circle gets larger as i move away, cant use paypal to buy aixiz from dealextreme, they dont accept my country
 
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The light from a laser diode is NOT emitted as a thin, straight beam but as a cone with 10..20 degrees aperture. If it produces a bright red circle of light, everything seems to be ok. You need

a) a heatsink to cool the diode, and
b) a lens to focus ("collimate") the spreading light into a "laser beam".

For both of these, get an AixiZ module (it's not very good at job a), but it's a start).

There's a good chance that running the diode at 200mA without heatsink even for a few seconds will have shortened its life drastically.
 
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when i ran it at 200mA it was always either in the chinese piece of metal with lens, or in its original casing from which i got it out of

what i dont understand, everywhere i saw that it was a major eye hazard etc...but i didnt feel any heat (from the beam) and i could look at it just fine even when it was max power...

bright red circle of light - its not very bright... and when i look at it...i can see the line...and its not very bright, as in eye straining

it looks like its not going over the lasing treshold...even tho amperage is good enough

can someone post pictures of a raw diode lasing ? ... like pointed at a desk at close range or whatever

is 1.7V enough for lasing ?
 
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Heat is not how you get the eye damage. laser light is dangerous because all the photons travel in the same direction in a tight beam. and your eyes have their own focusing mechanism. so when the two combine it not a good time. And the cheap chines dollar shop lasers are totally different than what you are trying to do. non interchangable parts. you need a good module go to www.hightechdealz.com the modules are inexpensive. How are you checking your ma? and a "raw" open diode is really bright. never look into it!!!!!!!!!!

michael
 
No, 1.7V is NOT enough for an LPC. I think it starts at something like 2.5V. Below it's just a LED which, with the lens in place and properly focused, will look like the laser beam ---o--- but will be very weak.

I still don't know what you mean with "which can output from 12mA to 400mA on 1.7-2.2V"... what input voltage do you give it? You need a minimum of about 5V.
 
i give the daedal circuit 9V on input, but when i use a voltmeter and put the probes on the legs of the diode, i get 1.7 to 2.2v depending on how far i have the trimmer set

the static resistor is 5ohm and the variable one is 100ohm, which, at the minimum setting, gives 12mA at the output

i am testing the amperage with a analog multimeter in series right before the diode

picture of the circuit
http://i41.tinypic.com/6z10mv.jpg

i am using a 1N4007 diode instead of the 1N4001 as in the proper DDL circuit, i think this has no effect on my problem tho right ? (4007 just allows more amps through it before dying)
 
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Testing with ampermeter is not safe.
Current from capacitor can blow diode.
The best way is to use 1ohm resistor.

Or connect ampermeter before capacitor.

Use just 5omh resistor to get 250mA.
Most likely...diode is dead, it should give about 2.5V of forward voltage.

1n4007 diodes are fine.
 
without diode connected, voltmeter reading on the + and - terminals gives me wall plug voltage - 1V
can i power the DDL circuit with a 4 battery rechargable (gives 5V)
 
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Can you post a picture of the dot (or circle of light) you get? It still sounds like you're just missing proper focusing.

Your driver can do 12..250mA; I hope you're aware that if you set the pot "halfway" (50 Ohms), the current won't be halfway between 12 and 250mA but rather ~25mA? In order to get 100mA, the pot has to be nearly at the low resistance end. Better use a 10 Ohm fixed resistance initially.
 
well even at 12mA it should lase right ? 12mA is more than what cheap chinese lasers use, and they still make a dot...mine doesnt

this trimmer has a really long range, that is i need to turn it a lot of times in order to change it significantly...so i always use the ampermeter when adjusting it...i dont rely on "halfway"

this is what it looks like at 12mA...on 200mA it just gets a lot hotter and like twice as bright but still no lasing

http://i43.tinypic.com/b9ajpu.jpg
 
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