Carrying a laser - my experience

Hey guys,
So last month I wanted to show my laser to a couple of friends and had to carry it in my bag.
In order to avoid it bouncing left and right I enclosed it in a case for laser goggles almost certain that there would be no way for the laser to turn on by itself.


Well, let me tell you one thing, there is always that little chance that something happens, and in fact, when I arrived at destination and pulled the case out of my backpack, a scary smell of plastic came out too.
I opened up the case and the laser was OFF, but a new hole was pierced through the case and the side of my bag in the inside was also marked by heat.

For the life of me I couldn't understand how that happened and for a good month I thought that the power switch was just broken/defected and would turn the laser on accidentally.

A couple of days ago I was again handling my laser and the answer to my doubts came to me, so I made this relatively short video where I explain it.

I hope you guys can learn something out of my experience.
Happy lazing!

What an unusual thing to happen, we must always be extra careful with lasers. Thanks for posting the video, good job figuring out what happened.

Alan

nikooo777 said:

Well, let me tell you one thing, there is always that little chance that something happens

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One thing you should know about lasers and any electronic DIY projects; murphy's law is always there to hunt you down

Hi Nickoo,
By the looks of your fix job for the switch, did you ever think about changing it out . i'm sure if you looked around that you could find a replacement . It's not that hard to do and for safety reasons look what happened. Sometimes it's better to wait till you can do it the right way . Well all in all glad to see you didn't get hurt buddy you dodged the bullet this time Wow !!

Rich

Don't feel bad. I had my small Sanwu go off in my pocket. Ouch !
When shipping I TAKE THE BATTERY OUT OR put a small plastic piece over the end of the battery to prevent it from starting up accidentally.

I built 5 MS Envies for a guy with M140 diodes that all output over 2 watts each. I spent a great deal of time explaining how to safely use these lasers, but he had one in is pocket and it managed to get turned on. It burned a hole in his jacket, but the laser was fine, even after it had discharged the batteries. So, I guess you never know what might happen to a laser being transported with the batteries in it.

Having leads on a laser that go directly to the battery like that is a bad idea in the first place.

It just turned on the laser in this case, but if you somehow managed to touch the leads to eachother that could have made quite a mess, getting very hot, melting the insulation off or perhaps even setting something on fire.

As for touching the case material: While aluminium oxide is a very hard substance it's not that hard to pierce a small surface layer, for example using your lead or a multimeter tip.

Anodized aluminium is not considered to be a reliable insulator, if you have a heatsink made from it you would not install two transistors or such if their mounting tabs are not supposed to be electrically connected to eachother.

Things made out of aluminium oxide thoughout are however good electrical insulators and you may find those in high temperature applications: Beryillium oxide is even better, but has its health hazards when cracked or chipped.

Pi R Squared said:

What an unusual thing to happen, we must always be extra careful with lasers. Thanks for posting the video, good job figuring out what happened.

Alan

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i have to agree with you here thanks for the good words!
Niko

ElectricPlasma said:

One thing you should know about lasers and any electronic DIY projects; murphy's law is always there to hunt you down

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Oh you're so right there! I grew up studying electronics and messing with it, and sometimes I'm surprised i'm still 100% intact hahaha.

Lifetime17 said:

Hi Niko,
By the looks of your fix job for the switch, did you ever think about changing it out . i'm sure if you looked around that you could find a replacement . It's not that hard to do and for safety reasons look what happened. Sometimes it's better to wait till you can do it the right way . Well all in all glad to see you didn't get hurt buddy you dodged the bullet this time Wow !!

Rich

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Hey Rich, The switch itself is perfectly fine, it works. These jumper cables are an extension that I can use if i want to plug the laser to the power supply directly without having to do weird tricks. They're mounted in parallel with the batteries.

trussmonkey25 said:

Don't feel bad. I had my small Sanwu go off in my pocket. Ouch !
When shipping I TAKE THE BATTERY OUT OR put a small plastic piece over the end of the battery to prevent it from starting up accidentally.

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Ouch! i was stung a couple of times by this buddy and it's definitely not pleasant!

paul1598419 said:

I built 5 MS Envies for a guy with M140 diodes that all output over 2 watts each. I spent a great deal of time explaining how to safely use these lasers, but he had one in is pocket and it managed to get turned on. It burned a hole in his jacket, but the laser was fine, even after it had discharged the batteries. So, I guess you never know what might happen to a laser being transported with the batteries in it.

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That's unfortunately true. What happened to me was pretty much the same and I'm glad nothing caught on fire and that the beam didn't make it through the bag.

Benm said:

Having leads on a laser that go directly to the battery like that is a bad idea in the first place.

It just turned on the laser in this case, but if you somehow managed to touch the leads to eachother that could have made quite a mess, getting very hot, melting the insulation off or perhaps even setting something on fire.

As for touching the case material: While aluminium oxide is a very hard substance it's not that hard to pierce a small surface layer, for example using your lead or a multimeter tip.

Anodized aluminium is not considered to be a reliable insulator, if you have a heatsink made from it you would not install two transistors or such if their mounting tabs are not supposed to be electrically connected to eachother.

Things made out of aluminium oxide thoughout are however good electrical insulators and you may find those in high temperature applications: Beryillium oxide is even better, but has its health hazards when cracked or chipped.

Click to expand...

Hey, you're right, however if you watch the video you will see that one lead was covered by some tape. Now i covered the second lead too with some electrical tape to avoid this issue from happening again.

I 100% agree with the aluminium statements, I was once electrocuted by a 450V~ heatsink because I forgot to insulate a transistor (part of an amplifier i built). It cost me 1 shock, an ipod and my motherboard (everything was connected together)

nikooo777 said:

Hey, you're right, however if you watch the video you will see that one lead was covered by some tape. Now i covered the second lead too with some electrical tape to avoid this issue from happening again.

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Why not stick a proper connector on there? Use a female connector and you negate that risk entirely - not sure if I'd trust some tape. Plus a proper connector would be more convenient too. Something like a small power pole connector could work. :beer:

Sticking a connector on there could be a good solution if it's mechanically snug.

Putting on some tape is the sort of thing that really works 99.9% of the time, except the 0.1% where you -really- don't want it go wrong. One idea could be to put a fuse in the positive wire just in case that would contact the negative or the case (when the switch is on).

As for the heatsink ordeal: be happy to walk away from that with your life. I once grabbed hold of an aluminium project box that some idiot built, and it was connected to one of the mains terminals. In this case he plugged it in such that it was connected to live, and i grabbed it in one hand while leaning on a metal post that was grounded.

Luckly there was a RCD on that grid that tripped, without that chances are realistic i'd have died (no chance of letting go of the device or post really, even if it's AC). I wasn't injured at all, but i guess the guy that constructed that thing got a bit of a scuff after i banged the unit on his head after the whole ordeal - i was 15 or so at the time.