Help me make this man understand...

First off, first post. I do lurk this sight occasionally, thou. Computer tech by trade. Hobbies include old vacuum tube electronics (mmmm... voltage), pyrotechnics, and firearms. Yes, I like my slightly dangerous hobbies. Anyway, enough of that. I just don't like to make a first post without saying a bit about myself. Kinda rude I think.

Anyway, here is the situation. I was visiting my brother the other day and my little nephew (13) is showing me all the stuff he got for his birthday. One of the presents is a laser pointer. Cool. I like lasers! So he points this fu*ker (don't know if we can curse here... heh) at the wall and the damn thing startles me it's so bright. I know a fair amount about lasers and know this is not good. I ask him if uncle can play with it for a while and send him off with the Xbox game I bought him. I examine the device. I don't see any name on it, but it's black with a silver tip. The warning lable says <150mW. I immediately go to yell at my brother. I love my brother, but he didn't really get the scientific mind from our father (marine chemist and industrial hygienist). He basically thinks I've over reacting and parroting our safety nut dad (they don't get along). Anyway. I let it drop, casually slipped the thing in my pocket. Thankfully my nephew didn't notice it missing before I left that evening. Of course now they want it back. I need to be able to lay this out to my brother so he can understand. Facts and figures will just graze off his thick skull. Was considering burning the shit out of him with the damn thing (joking.. joking). Ideas?

Show him what it can do. If it's strong enough to light matches etc, it should scare him enough that he listens to you. If all else fails show him pictures of laser injuries, like the one on rog8811.com, that should set him straight.

Prototype said:

Show him what it can do. If it's strong enough to light matches etc, it should scare him enough that he listens to you. If all else fails show him pictures of laser injuries, like the one on rog8811.com, that should set him straight.

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Burns a brown paper at close range with no problem. You're right, that'll scare the mess out my sister-in-law. Heh... this is the women who won't let me take the kid to the range to shoot .22s because it's too dangerous. Luckily I doubt my nephew has even played with the thing. In was still in the little flip-top watch box when he showed it to me. He's much more interested in video games. They ain't getting it back, thou. The stupidity of people amazes me sometimes.

With the 1W 445nm I have, I find telling people you will hear your eye physically pop if it hits your eye enough of a deterrent that they don't want to touch it.

Over emphasise slightly to keep the safe, these things will easily blind an eye and at best leave a permanent black spot in the eye. Definitely not a laser for anyone <16 unless they're particularly responsible and have researched the hobbys them selves and understand the dangers.

Asherz said:

With the 1W 445nm I have, I find telling people you will hear your eye physically pop if it hits your eye enough of a deterrent that they don't want to touch it.

Over emphasise slightly to keep the safe, these things will easily blind an eye and at best leave a permanent black spot in the eye. Definitely not a laser for anyone <16 unless they're particularly responsible and have researched the hobbys them selves and understand the dangers.

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Goes the same with vacuum tube amps and such. For example: I'm working on a home built amp based on a 6550 tube. The plate voltage is 645 V with a current of 210 mA. That will kill you deader than shit. You don't "play" with this stuff. You know what you are doing first. I got hit by a 800 V cap once. Thankfully the circuit was dead, the cap was pretty small, and I only got hit with the residual charge. It literally knocked me off my stool and shorted out my entire nervous system. I don't know for how long. I just woke up on the floor. lol!

Pyroelectric said:

I got hit by a 800 V cap once. Thankfully the circuit was dead, the cap was pretty small, and I only got hit with the residual charge. It literally knocked me off my stool and shorted out my entire nervous system. I don't know for how long. I just woke up on the floor. lol!

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This is why there's the rule to use only one hand, managing charged capacitors ..... and why having an 1Kohm 10W resistor with insulated cables and clips as tool is a good idea .....

I worked sometimes repairing old Xerox fast copiers (the ones that uses 4 giant flash lamps, instead a filament lamp), and i learned to have a lot of "respect" for those big box-sized "25uF 3950VDC" coupled capacitors ..... especially for the "funny" warning printed on them ..... "WARNING, STORED VOLTAGE MAY BE LETHAL" ..... LOL, yeah, 25uf charged at almost 4KV "may be" lethal ..... also a bullet in the head "may be" lethal, right ? ..... :crackup:

also try google images of a burned retina and say it came from a laser pointer at half that power.

michael

HIMNL9 said:

This is why there's the rule to use only one hand, managing charged capacitors ..... and why having an 1Kohm 10W resistor with insulated cables and clips as tool is a good idea .....

I worked sometimes repairing old Xerox fast copiers (the ones that uses 4 giant flash lamps, instead a filament lamp), and i learned to have a lot of "respect" for those big box-sized "25uF 3950VDC" coupled capacitors ..... especially for the "funny" warning printed on them ..... "WARNING, STORED VOLTAGE MAY BE LETHAL" ..... LOL, yeah, 25uf charged at almost 4KV "may be" lethal ..... also a bullet in the head "may be" lethal, right ? ..... :crackup:

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4KV of DC? How many cans? doesn't matter really. The customer would just walk in and ask where is the technician and where did this smoking pile of ashes come from? lol!

Don't have to tell me. heh Actually best to wear a belt and tuck one hand in there behind your back. I always wonder for just how long my heart was stopped? lol! I had an Audio Research D250 that I bought cheap and repaired. It had a 550 joule power supply. That baby had like 9 big 450v cans in the supply. I forgot how many mics they were, but just tuning that thing on scared me. Used to dim the lights in the house.



:eg:

get a lens and burn some stuff with it. Then remind them that your eye does exactly that: it focuses what you see down to a tiny area on the back of your eye. All that power focused down to that small of an area is definitely dangerous. But hey, maybe find a <5mW greenie and give that one back to your brother.

That is an excellent idea. The Lyra series from LaserGlow or the Core from WL are both excellent 5mW greens, if a tad pricey for their power. I've got a Core and I love it, lasts forever on a set of alkalines.

Prototype said:

That is an excellent idea. The Lyra series from LaserGlow or the Core from WL are both excellent 5mW greens, if a tad pricey for their power. I've got a Core and I love it, lasts forever on a set of alkalines.

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Yeah, I was thinking of getting him a safe replacement. Perhaps something cooler looking. I've been searching online for the one I confiscated and the closest one I can find that kinda looks like it is this: DealExtreme: $53.44 200mW Green Laser Pointer Pen Black It pretty much looks like that minus the silver ring mid pen and the silver shirt clip. I'm guessing this is cheap Chinese? It doesn't feel very well built. It has no name on it anywhere, so I haven't a clue who made it.

I was thinking maybe replace it with this: Green Laser Pointer from Wicked Lasers - Executive Series

Much cooler looking and safe. I don't the kid care, though. He'd probably be much happier with a 360 game. heh.

Uncle will just hold on to the dangerous one. Not that he's having any fun with it or anything. Gas lasers would be more my speed.

Many people won't trust your word until they feel the pain first-hand. I know that happened with some neodymium magnets I had. "It can give you blood blisters if they pinch you, or even BREAK YOUR BONES." Do they listen? No they don't. "OH MAN, that is a strong magnet!" YA THINK?!

So take his hand and burn it with the laser. At those powers it should easily do so. "HOW DO YOU LIKE THAT?" Then tell him to imagine that entering his eye, or the eye of his son. Enjoy your vision? Enjoy paying for thousands of dollars in medical bills, and that's if you're lucky? Want your ass sued to bankruptcy if he injures someone else?

I'm wondering where he got it. 150mW pens are not too common, nor cheap.

Just get him an Xbox game to compensate.

-Tony

I once told my nephews that my laser would blow there eye up, which was bad because now they wont even touch it, well good actually lol

Pyroelectric said:

4KV of DC? How many cans?

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One ..... was four old type metal box capacitors, gray painted, sealed and filled of oil ..... of the size of a shoe box, approximatively , (with M8 terminals, insulated with flanged ceramic sockets, on the top ) ..... like this one, but more old (this one is 60uF, but they made also 400uF, if you need to filter out something more :eg



BTW, nice final stage you have there ..... i'm a bit envious, now

I've been shocked on one hand by my 200kv Tesla Coil my 9kv/30ma NST and a 30kv tazer. But the worst shock I've ever gotten was a two handed (current through the heart) shock from a 320v 440uf capacitor. I too woke up on the floor feeling like I just got punched in the gut. I was lucky I wasn't killed.

-Tony