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Learn From Mistakes That Can Happen To Anybody...

DJNY

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This thread shouldn´t die. My contribution below:


#don´t simply trust Ebay / Chinese laser power listings. In both directions (low/high power)
When I got my first 1mW laser back in 2009, I only knew about the blinking reflex for lasers >5mW. I played around with it as I thought it´s totally safe.
Now I know that the laser had at least 30mW.

#seeing no green light coming out of a 532nm, doesn´t mean that it isn´t emitting photons
When it is too cold for producing green light, these cheap green pens sometimes produce only +50mW of IR.
Once, back in 2010, when I got two DinoDirect claimed 100mW pens (in the winter-time) I started them, but saw no output. I then carefully looked closer and saw a faint red-light. Back in the days I knew shit about IR. I thought that they sent me a very low powered red laser. Put after putting it onto my LPM, I read +60mW of this "low powered red laser". Once it was heaten up a bit, it turned to green output.

#there are also non-rechargeable 3.6V 14500 cells out there
http://laserpointerforums.com/f48/l...gh-diffraction-grating-87243.html#post1268975
 

millirad

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Wow that was a close call. Good information for those who really have no idea how the majority of greenies work. I'm sure many think they are direct diodes with "pure" emission. Or that the IR filter removes all of it.

#seeing no green light coming out of a 532nm, doesn´t mean that it isn´t emitting photons
When it is too cold for producing green light, these cheap green pens sometimes produce only +50mW of IR.
Once, back in 2010, when I got two DinoDirect claimed 100mW pens (in the winter-time) I started them, but saw no output. I then carefully looked closer and saw a faint red-light. Back in the days I knew shit about IR. I thought that they sent me a very low powered red laser. Put after putting it onto my LPM, I read +60mW of this "low powered red laser". Once it was heaten up a bit, it turned to green output.
 
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DJNY

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^ yes, guess I learned it the harder way

After the battery explosion, I had a tinnitus for about half an hour. Was sitting 2 meters away.
 
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Before buying a laser(s) (diode(s)), think about who you're buying them from.
  • Does this person have much experience handling laser diodes?
  • Do they know the high ESD risks associated with them? (Proper handling procedures)
  • Gas laser tubes are very fragile and thus carry their own shipping and handling risks.
  • Even solid state lasers can be knocked out of alignment when dropped hard enough. (Padding)
  • Take a look at their feedback rating. Try to find ratings for the exact thing you're planning to buy. (eBay)
  • If the source is questionable and the price is low enough, buying multiples increases the chances that at least one of them will work.
  • Is it really worth the risk? Get out the calculator and do a little cost benefit analysis.
  • If something goes horribly wrong, is there some type of buyer protection to fall back on?
 

Marco Polo

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It's very reassuring to see that even the experts make mistakes and had to learn some things the hard way. Tons of good advice here, and makes me feel less bad about my C6 disaster. Well, here are my contributions:

1) When working with a C6 host (or any round host with round heatsink) make sure that the heatsink can't spin unexpectedly. In the case of the C6, the "rim" that holds the heatsink in place might be too short, and the top ring won't put enough (or any) friction on it. Thus, when adjusting something like the lens, the heatsink will rotate, and the module will rotate with it. This can twist the diode pins off, and that can make a person sad.


Best to put an o-ring, or make an o-ring and use that to secure the BOTTOM of the heatsink rim such that the top ring can hold it in place. Properly done, the heatsink will take more force to spin than one can feasibly put on it.

2) If a switching transistor on your laser's power supply board has a heatsink on it, don't run the power supply without that heatsink, or else it will stop working....


3) If you ever drop your keys into a river of molten lava, don't go after them, because man, they're gone. (Okay, that wasn't mine, Jack Handey said it.)
 
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alennn

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This thread is really useful for beginners like me! Thanks to eack and every post! :)
I haven't done any mistakes yet and I don't want to either.
 
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Always double and triple check polarity before applying power. This goes for anything polarized, such as
laser diodes (or any other kind of diode), LEDs (even high power ones), drivers, batteries, power supplies,
transistors, tantalum and aluminum capacitors, and integrated circuits.
 

ECBL

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These are all great experiences to refer back to... especially for someone new like myself. I love this stuff, I soak it up like a sponge... hopefully I can avoid some of these situations.

The biggest mistake I've had so far was taking three perfectly good (but cheap) burner diodes I had successfully harvested and thinking I could just wire them up to any driver. I had a SL 1.2A laying around prior to using it in my M140 build, so I tried it on the first diode...
got nothin' but an insanely hot Aixiz module... Hmm, desoldered it and tried again with the second diode... same damn thing. Yea you get the idea. The only difference with the third diode was that it actually lit up quite nicely for a fraction of a second before dimming down to almost nothing.

At least I didn't ruin the driver in all the madness... Lesson to be learned: Do research prior to building!
 

ru124t

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I guess by some standards I am a noob, as I have only been here a year. I have, however , have made a number of rookie mistakes and will list all I can remember here as a reminder and a learning experience to any reading.

- Don't charge your 3.0v tenergy batteries in a charger meant for 3.7v batteries. They may charge faster but the increased voltage will blow a laser that is meant to have 3.0v batteries. Case in point , I either put them in the dragon laser Spartan backwards or they were charged too much. The inside of it smells like burned plastic.

- When soldering diode leads together check the length required before doing it. On my first build , I had to cut them once finished because there was simply too much wire to fit into the host.

- In Canada it is illegal to import lasers >5mw . If it gets found by customs, it will be destroyed.
 

starlight

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Always use a beam stop. Last night taking pictures and didn't notice my dot was hitting the couch.

I was 15 feet away and I have a 1 inch toasty little mark now in the arm rest.

 
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Don't ever let alcohol, acetone, or any
other nonpolar solvent touch an acrylic
lens. Clean only using distilled white
vinegar and distilled water. Try only
flushing with the liquids first, then wipe
with cotton swaws only if absolutely
necessary. And use the good kind that come
sealed 2 in a package. You can get them
for free while waiting during any visit to
the doctor's office.



The chunk out of the center happened when I
removed it carefully using a hammer and
punch. But if you look around the edges
you can see that it is cloudy from being in
contact with isopropyl alcohol. I know
better than this. I have no idea what made
me reach for that bottle of alcohol, and
more than once.

:spank:

It makes a pretty good diffuser. The
output power went from 90mW to almost
nothing.
 

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Alaskan

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Don't hook up your laser diode to a DC power supply and turn it on, even with the voltage turned all the way down, a spike will likely kill your diode unless a very expensive lab power supply, but don't even do it then.
 




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