Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Learn From Mistakes That Can Happen To Anybody...

hxdrummerxc

New member
Joined
Mar 31, 2010
Messages
179
Points
0
Well I thought that I would add a little something here....

Don't get so excited that your 100mW green module came in the mail,
That you neglect to watch which way you put your battery(s) in.

I just got my 100mW green module in the mail today. Hooked it all up,
had it working for about two hours.

Then I took the battery out to look at something, I was too excited that I wasn't paying attention when I put the battery back in.

I tried to turn my laser back on and nothing happened. So I took the battery out and realized what I did. Now my laser wont power anymore. :(

$70 for two hours of use..... all for one simple mistake.
 



Eudaimonium

Well-known member
Joined
Feb 5, 2008
Messages
6,311
Points
83
I needed to shorten a heatsink one time, to be able to nicely fit a battery pack, 3x AAA or 14500 in there with plastic sleve, the HS was just around 3 mm too long for it.

So I get a simple saw and cut off the end.
Then I pressfit the aixiz with SF-AW diode, and boost driver set to 170mA.

What I didn't forsee is that for some reason, one tiny bit from sawing shorted out the current setting resistor on the boost driver.
You can guess the rest, the diode lased about a microsecond , suffering the 0.7 A though it.

But that is not it.
The diode payed me back severly for feeding her 0.7 A, and instead of turning into LED like all other polite diodes would, she decides that it would be cool to simply turn into open circuit. Reminder = boost converter was used.

So that is both diode and driver combo gone to waste.
I still have that bitch diode, to remind me that there is no extra care, when handling anything about lasers.

Point is that you should check and recheck everything three times before power up. I should have blown out the particle leftovers with compressed air or something, as obviously my breath was not enough.

This may not be that common, as you really have to be unlucky for such row of events( not mentioning previous worries about pressfiting),
But I thought I'd share anyhow.

Also, one more tip:
When you have a heatsink machined to pressfit the aixiz module in there, DO NOT IN THE NAME OF THE LORD use the back barrel only because you feel like it.

I used it, only to find out that it 'plowed' into aluminum halfway there.
If only I used the head of laser (or mine ! ), I would not have to destroy the heatsink and glue the thing in place after I drilled out the remains of back barrel from the HS.
 

Mohrenberg

New member
Joined
Aug 30, 2008
Messages
6,924
Points
0
Tad off-topic but it's a valuable lesson :)

I once got very drunk at a bar. Being hit on by another woman, I decided to take the bait. Although my friends were ready to leave and pleaded with me to leave with them, I decided to stay. As the night went on and I ended up at these women's house, I began to sober up and realize what I was doing. Not only was this woman "overweight" (by about 75 pounds) but her hygiene was found lacking in certain areas.....

So I bailed and got my sister and brother-in-law to come pick me up as I waited on the side of a highway for them. I ended up having to hang my hand out the window on the way home (again....hygiene is very important.)

I learned that day if I am drunk and have 10+ people all telling me the same thing, I should probably listen.
 

Crazy Jay

New member
Joined
Aug 31, 2009
Messages
2,203
Points
0
Tad off-topic but it's a valuable lesson :)

I once got very drunk at a bar. Being hit on by another woman, I decided to take the bait. Although my friends were ready to leave and pleaded with me to leave with them, I decided to stay. As the night went on and I ended up at these women's house, I began to sober up and realize what I was doing. Not only was this woman "overweight" (by about 75 pounds) but her hygiene was found lacking in certain areas.....

So I bailed and got my sister and brother-in-law to come pick me up as I waited on the side of a highway for them. I ended up having to hang my hand out the window on the way home (again....hygiene is very important.)

I learned that day if I am drunk and have 10+ people all telling me the same thing, I should probably listen.
I think he was right on the topic. :p

Glad you sobered up in time. Don't listen to any 10 people... just listen to your family otherwise you might be guided to jug down enough beer to kill ya or even worse.... eat a dozen of those brownies :D
 

Morgan

New member
Joined
Feb 5, 2009
Messages
2,178
Points
0
Hey, great thread. I'll be checking back in the future I think...

Here's my 2 pennies...

I learned a lesson about Flexdrives that, thankfully enough, (and unusually for this thread!), didn't end in disaster but may bite someone someday.

When testing diodes I naively often used to hook them directly to a bench PSU. This, I discovered is not recommended but the output was stable enough to not affect reds and PHRs had responded well also. Even GGWs seem to have gone unscathed but I changed my ways as this is not good practise and the costs are a touch higher with x6. So I moved on to testing them with a driver regulating the current properly and this is where I learned a lesson...

During my direct hook-up testing, I'd always been as careful as possible to first set a desired voltage then turn all output to nothing, short the PSU leads, then hook up a diode and slowly ramp the current. This will not work with a Flexdrive in the way as the low voltage shutdown will prevent any current reaching the diode and the voltage output of the PSU will not go above the ~2V point. NO MATTER HOW MUCH CURRENT YOU TRY AND PUMP IN!!!! :tsk: Confused me for quite a time that one.

I have discovered though that a Flexdrive can take around 1.2A in this way, and survive, but I wouldn't recommend trying it. It gets really, REALLY hot and squeals like a stuck pig! Like I said though, it survived and is now being treated correctly driving a small IR diode that outputs 315mW. (It's not the squealing one that I repaired recently for LaserBoyStuart in case anyone was wondering. That one was powered open circuit and just squeals ALL the time!)

You live and learn...

M
:)
 
Last edited:

Freitsu

New member
Joined
Feb 26, 2010
Messages
50
Points
0
Adding another one here that happend to me yesterday...

I soldered a GGW diode onto rckstr driver and little did I notice that I had soldering iron-tip resting against AixiZ module housing. Needless to say that diode didn't even go LED, it went straight to BR heaven. :( (luckily I had a chance to test it before soldering it onto driver, it shined very well......)

Lesson learned this time, keep soldering iron well clear of housing and don't just focus on the actual soldering place.
 

jayrob

Well-known member
LPF Site Supporter
Joined
Sep 21, 2007
Messages
9,874
Points
113
All of these experiences are great for learning...

I have seen often, that some have not used enough care in mounting the FlexDrive inside the pill. It must not be able to 'short out' by making contact to the aluminum pill. (this is normally a possibility in many builds)

Also, with many of my kits, you must thread the pill/heatsink assembly into the head of the host upon final assembly. It is very important to make sure that the heatsink does not 'twist' or 'spin' separate from the pill. This would let the wires get twisted, and possible ruin the build...

And another key part of a properly finished assembly, is to make sure that the heatsink is not 'loose', but that the pill (or the host, which ever the case may be for the build), is holding the heatsink firmly in place. Two reasons for this:

1. When the heatsink is held firmly into the head of the host, the entire assembly (including the host itself), is in effect, the heatsink.

2. If your heatsink is loose, you could easily cause damage just by trying to focus. (if the heatsink were to 'twist' or 'spin')
 

cistercian

Active member
Joined
Nov 21, 2009
Messages
317
Points
28
ESD.Electro-static discharge.I can't count the number of VMOS FET's I have ruined...just by touching them!Laser Diodes are horrible too.Static charges far below what you can feel will kill them outright, or shorten the lifetime to minutes.I have killed 5 or six laser diodes just from the ESD that occurred during handling.2 of them lived...a short time.Stuff with a damage threshold as low as older aluminum gate VMOS FET's were horrible to work with.They work great, if they survive installation.I now use micro fine wire to short all pins together until the device is in the circuit.That works well...unless you forget to remove it first.That ends badly.
Remember this important law:The likelihood a super trivial mistake will cause epic damage is typically directly proportional to it's price.A rare super exotic LD will fail...as you open the packaging.
 

awlego

New member
Joined
Oct 9, 2009
Messages
160
Points
0
After killing my first few diodes my advice is: SLOW DOWN!

I know new lasers are exciting... believe me, I know. But I learned the hard way 3 ways not to assemble a new laser. All can be prevented by slowing down.

1. Forgetting to discharge the capacitor's when making DDL drivers - I know hooking up and testing your new laser is thrilling, but take a second and double check this.

2. Trying to solder your driver to your diode with the batteries still attached to the driver... again - I was too engrossed in thinking how happy I was that my new laser was almost finished and ended up killing it.

3. Dropping it. As it turns out, dropping whole lasers, or even just diodes, is not good for them. I know in the heat of the moment of getting your hands on a new laser it can be easy to forget you're holding a fragile diode while you reach for the soldering iron or the a clamp, or whatever. It's easy to drop when you're rushing to complete it.

So my advice: SLOW DOWN. You will never regret taking the extra minutes to double check and be absolutely sure you're doing everything correctly. You will regret loosing your valuable money and precious time.

-Awlego
 

Valkonin2

Banned
Joined
Jun 12, 2010
Messages
6
Points
0
I once left my 200 mW green laser in my pants and put the pants in the washing machine. Of course this smashed the laser, caused shape-shifting before it completely stopped working after changing the batteries. :wtf:

On a double fail, I don't keep them in my pockets anymore 'cause they press against my wallet and burn through my pants! :mad:
 

roguexx

New member
Joined
May 27, 2010
Messages
34
Points
0
I was soldering together my first diode driver from scratch, i was almost done... unplugged the soldering iron and it started to slip off the table to i grabbed the correct part of the handle and moved the stand i have for it so it didnt slip again... the stand was metal... and extremely hot... i still have burn marks on my thumb and pointer finger.
 

Eudaimonium

Well-known member
Joined
Feb 5, 2008
Messages
6,311
Points
83
I was soldering together my first diode driver from scratch, i was almost done... unplugged the soldering iron and it started to slip off the table to i grabbed the correct part of the handle and moved the stand i have for it so it didnt slip again... the stand was metal... and extremely hot... i still have burn marks on my thumb and pointer finger.
You mean one of them stands that are cut out from 2x3 inch tin?

Well too known , they get exeptionally hot - I simply keep the handle of my soldering iron on the table so it lays horizontaly on it, end of the handle where cable is sits just on the edge of table so the cable does not get in the way , and this method of holding the iron served me well for couple of years now - it is always near when you need to tin the wire or something (I hold the wire in one hand and soldering iron in another).

I think I threw that stand in trash when I saw what it actually is, it does nothing but burn your fingers.
 

Mato92

New member
Joined
May 30, 2009
Messages
47
Points
0
I make lasers using a regular plastic box, not a flashlight housing. My first laser died because of a bad construction - the switch contacts accidentally touched the heatsink of LM317...So, when building a new laser, I put an isolation tape on switch contacts, just to be sure it will never happen again :)
 

Ramsey_innovations

Active member
Joined
May 10, 2009
Messages
375
Points
28
Back when LOC's were $75 I had an inncident with a back reflection off of a TV that just barely streaked across the aperture and suffered C.O.D. instantly.

I also tried to clean a particle of the window of an SF-AW210 and it barely took any pressure at all for it to detach. I successfully decanned it but it only lasted a couple of weeks before it died. Some of the SF diodes are fine but others are defective, upon close inspection after decanning it is obvious that the bonding cement was applied half ass at best. I remember the window was way off center as well. It may have been placed on its side just after manufacturing, before the bonding cement fully cured causing the window to slide to one side, just speculation.:thinking:

Anyway, great thread Jay! It was a good read and I'm sure it will only continue to get better, I'm subscribed!:thanks:
 

millirad

Well-known member
Joined
Apr 28, 2009
Messages
2,417
Points
63
Wow, didn't see this thread first time around. Well I'll add this info to the thread just because of how strange it is. No one will be doing this these days. Long ago, I was scratch building an argon laser and it was a design similar to the old Scientific American magazine article. I purchased a glass diffusion pump for bringing the gas laser to an extremely low pressure. This was a "mercury" diffusion pump. I purchased 2 pounds of mercury to run the pump. The mercury was stored in a glass bottle inside a brown paper bag. The laser was being built inside of my garage with concrete floor. Forgetting how heavy the bottle of mercury is, I picked up the brown paper sack and "crash". The bottle ripped through the sack and burst giving me the worst mercury clean-up ever. I had to sweep carefully with a hand broom and used sheets of copier paper to scoop and put the mercury into a beaker. It was the most tedious recovery operation and the scare about having lots of toxic mercury out in the open. I decided that if gold miners could be around the stuff that I wouldn't worry too much. I was ok, but you can't be too careful with mercury. Now I have a blue 445nm Class IV running on 3XAAA primary batteries. Much easier than an argon from scratch. Thanks Dave!
 

jayrob

Well-known member
LPF Site Supporter
Joined
Sep 21, 2007
Messages
9,874
Points
113
This is great input from all you guys...

No matter how experienced you are, you can benefit from reading about how mistakes can easily happen... :cool:
 




Top