Mixing an invisible laser and a fire alarm made for a disastrous demo Happy New Year, gentle readers, and welcome once again to Who, Me? – The Reg's regular roundup of rapscallions and rascals committing tech atrocities and (sometimes) getting away with it. This week it's got a sci-fi twist because the disaster in question involves lasers. The story comes to use from a reader we'll Regomize as " …
Cooling fan(s). Of the same era (maybe a trifle earlier), think Cisco AGS routers and desktop PDP-11 kit. Early 1980s to mid 1990s was peak fan noise, when processor and bus speed nearly outran the technology to be air-cooled. Lots of money went into heat transfer technology in this time period. Such tech also helped with the physical down-sizing of lasers and etc.
Newer servers do that, and those 8 cm fans often go from 5000 rpm as maximum down below 2000 rpm. But go back a few generations: Fans never go below 5000 rpm, and have a defined maximum of 15000 rpm. And we still talk about 8 cm fans here, not those pizza-box servers with their turbines. Those 8cm fans are still listed, you can still buy them!.
For comparison: 4 cm fans can exceed 30000 rpm
I actually saw those 15000rpm 80mm monsters PFR0812XHE on a dell 2U, fairly recently and a PFM0812DE-01 on gigabyte 2U servers and they do that because they expect GPUs to be installed AND to 280W on a 1U heatsink. In a 2U chassis. Ridiculous.
All 4 fans were stuck at max rpm because the management software was bricked.
Quite contrary! Those lasers are partly waterproof since they need a lot of water for cooling. You invest 10 kw of energy to get a laser with less than 1 watt. Everything between those two numbers is heat. Dave made a teardown on an old concert laser which eats 24kw of energy.
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Back in December of 1993 I was setting up a laser T1 link between Redwood City and Newark. The clueless owner brought me a burrito for lunch ... and hung the bag on the fucking laser!
I swore, he grabbed tor the bag, and got greasy fingerprints all over the glass.
Have acetone, ethanol, DI water, q-tips and lens paper, will travel ...
I suspect that the lab in the story might have been a chemicals lab in a previous life and the water release was for stuff that can either oxidize stuff in other ways than high temperature combustion or do damage in other "fun" ways. I've seen a few chemical labs that had a water deluge system to get things diluted fast if the nasty stuff ever left the fume hood. The combination with a gas fire suppression (Halon?) would be another hint in that direction as apparently they weren't expecting a whole lot of water to be sufficient to deal with whatever is on fire (or dissolving). I wouldn't want to be in the lab if there was a Halon release though. Only 301 is breathable in low concentrations iirc and the rest you REALLY don't want to breathe in, even ignoring the asphyxiant/oxygen displacing qualities
Many moons ago, maybe 1983 bright and early one fine morning I was on the roof of the old Ford Aerospace Building One on Fabian in Palo Alto, trying to re-align a new laser network link to a building across Hwy 101. I got tackled by a couple largish MPs ... Seems that some military big-wigs were about to arrive to inspect one of our satellites (unlaunched, being built in the high-bay), and the two security guys heard someone talk about "jake's up on the roof with the laser, that should sort 'em out". Myself and the two talking about me were detained, taken to a small room & questioned. Seems the security detail wasn't all that versed in the power output of a 5mW HeNe laser, in their tiny little brains we were conspiring to roast the brass.
We had the last laugh. The laser link was part of the demo that the brass was there to observe. We were "rescued" from the grilling after about an hour, and allowed to get on with it. The security guys got a very public dressing-down from a rather technologically cluefull Colonel (in full dress) for wasting his time ... After we concluded the demo, the Colonel sent the security guys to get pizza for lunch and sat & ate with us, discussing the ins & outs of "modern" wireless (laser) networking.
Nothing. How do you cool the water? Water cooling is pretty efficient for moving heat, but sooner or later you have to dump that heat somewhere, and that probably involves noisy fans and heat exchangers. Also, more moving parts to break than just using lots of noisy fans to start with.
(I'm assuming you don't want the massive water bill you'd get from putting a continuous flow of water down the drain, cold in, warm out)
Many years ago I was cutting an exhaust off an old range rover, it was a hot humid day and my safety goggle kept fogging up so I took them off and replaced them with safety glasses. I did see a bit of swarf come off the exhaust towards my face and sure enough it found the gap between my glasses and forehead.
I went to the doctor who couldn't see anything, do not rely on a GP in a situation like this got to an eye A&E department.
I had no problem for 20 years then the eyesight in that eye started to go bleary, over the next 2 weeks it got worse and I went to see a doctor then A&E, it turned out that the swarf had gone into the lens of my eye and sat there for 20 years doing no harm until I had an MRI on my knee, it appears this was enough to get the bit of metal moving and it has migrated back through the lens and made a hole allowing liquid from my eyeball to infiltrate the lens causing a cataract.
I had to have the lens replaced with a synthetic one, quite a traumatic procedure if you don't have an anesthetic, especially as in my case the lens pouch split as the lens had become so swollen, luckily the surgeon managed to catch that before it split all the way around dropping the lens into the back of the eye.
If I had gone to a proper eye department when the original incident had occurred the eye would have been examined with a microscope and the swarf would have been removed saving a couple of months of anxiety later and a period where I was effectively blind in one eye for 3 weeks.
A thumbs up for the above comment. Not because I enjoyed reading your sufference, but because it is a cautionary and poignant tale.
A thumbs up can have two meanings. Just like when a family death was posted on Facebook and received multiple thumbs-up. Not because people were happy to read about the death, but there is no button for "thank you for letting us know".
A good friend of mine does helicopter mechanical work for a government contract. He lost an eye doing youth things years ago and has a prosthetic eye.
One day the brass for the contract were visiting and waltzed out on to the production floor, right past the safety gear required sign. My friend walked up to the biggest of the big shots, removed his fake eye, and politely said "That sign is not a suggestion".
My friend quietly went back to work as safety googles were hastily issued.
On the spin side this validated how seriously the company took procedures. The contract was renewed and continues to this day.
As the storyline was laid out, I expected a slightly different scenario to unfold.
Mention of the invisible UV laser led me to think the fire alarm had UV sensitive flame/arc detectors installed, which were triggered by the laser. But regardless of the mechanism, the outcome would have been pretty much the same......
The late 1990s... printers on networks... writing monitoring software. Nice new feature added to the printer management tool to alert you when a printer had a problem. The idea was two audios would play - i.e. "Sales Printer" and "Out of Paper".
All sounds safe... but we are devs in our 20s... so our test audio is a little less than safe. Test audio samples included Cartman quotes, rude noises, Red Dwarf, Explosions... you can kinda guess.
We needed to run a test. What would happen if ten printers all threw an error at the same time? Would the software handle this okay?
So with various people stationed around the room, at the same time we all threw printer doors opened, pulled out trays, caused multiple errors.
At that same moment the door into the lab started to open...
Our test worked, the only problem is that the Managing Director was walking into the room. On a tour. Potential new client. THE Head of a very large Japanese Printers division was visiting from Japan.
He walked into a room to be hit with a cacophony of rude noises, explosions, South Park, Father Ted and other random quotes...
Yeah - do the maths. Ten printers, two audio clips each... but also multiply by four test PCs. It was a little "noisy".
Also as we were all next to the printers, we could not turn speakers off quick enough.
Some interesting expressions on the various faces involved.
I'm sure I've told this story before, but many years ago - late 90s - when I was a mere whippersnapper fresh out of university and in my first job, I downloaded a Father Ted screensaver to my work PC. It blanked the screen and then played a random audio sample from Father Jack - "drink!", "arse!", "girls!", "feck!" and so on, to the accompaniment of the same word on the screen in blackletter font.
Hilarious. For about 5 minutes.
So I moved the mouse to exit the screensaver, and got on with my day. Logging customer issues, playing back voicemails and having to turn the PC's speakers up to hear & transcribe them... yeah, you can probably see where this is going.
I was called away from my desk, or maybe I wandered off to get a coffee, can't remember.
What I do remember is that when I ambled back onto my floor of the cubefarm a while later, that bloody screensaver had kicked back in, and the PC was loudly yelling DRINK! FECK! ARSE! to the entire floor.
Whoops. One more to add to my large collection of "sink into the ground" moments...
A few years back, a colleague of mine retired. I shared his office. He had the typical old school tech's office, with piles of half built or half disassembled equipment everywhere. Basically it was bad enough that even the health and safety officer stopped visiting (although that might have something to do with the fact that one day the health and safety officer visited to talk to me about something. This tech suddenly appeared beside him, sharpening an already very sharp axe, that he usually used for chopping cables.
He built all sorts over the decades, ranging from small, but surprisingly good, amplified breakout boxes (that took the inputs and outputs on a Soundblaster and provided line level inputs and outputs through phono jacks, as well as a stereo 3.5mm amplified headphone jack) to an RS232 based network for serial terminals.
I miss the days of sitting there working on something, then hearing a small explosion followed by a "Fucking hell", as some circuit he was working on blew up in his face.
Anyhow, I was helping him clear out his office when he retired. Sadly, had to throw most of it away, but I was fascinated to find 3 quite small (about 30 centimetres long, with a 3cm diameter) but definitely dangerous looking lasers.
"quite small (about 30 centimetres long, with a 3cm diameter) but definitely dangerous looking lasers."
Sounds like a late '70s or early '80s design HeNe. Red beam, 632.8nm, most likely under 5mW. The power supply for these can give you quite the zap (around 2500V at 5mA), but the output is fairly benign, as long as you keep it away from the eyes. Useful at over 1000 yards/meters under ideal conditions with proper collimation. Cheep and cheerful, but bulky by today's standards.
Ah yes, the days of mysterious beams flashing from one end of campus to the other. We never did get the lowdown on who was doing what, but there were plenty of candidates in Chem, Physics etc. Green was probably Argon-Ion, Red the HeNe. The only laser I ever worked with produced a 1 microsecond pulse at 1.06 microns, so no showing off with that one. Neodymium YAG glass, if anyone cares. Part of the rig was a delay line consisting of 100m of coax still wound on its reel, artlessly placed on the floor. Simple but effective.
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