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What Could You Do With 120 Laser Pointers? 266

lazed-dazed asks: "I've recently come into possession of a large number (120 of 'em) of keychain laser pointers (minus the fancy diffraction adapters, though the specs are the same). So, Slashdot, I ask you: Can you give me any project ideas for these low-wattage bad boys? Holograms? Fancy cigarette lighters? Laser cannons? The crazier, the better! Oh, and don't bother suggesting cat toys."
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What Could You Do With 120 Laser Pointers?

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  • by gl4ss ( 559668 ) on Thursday November 20, 2003 @05:09AM (#7518267) Homepage Journal
    and attach it to some tree branch.

    that + some wind should look eery enough when it's foggy.

    oh yeah attach some death trap it to keep it from being stolen.
  • by PB8 ( 84009 ) on Thursday November 20, 2003 @05:12AM (#7518277)
    Attach the 120 laser pointers to 120 dogs, after making them activated by barking and/or tail wagging. Release dogs at a cat show.
  • experiments (Score:2, Insightful)

    by igny ( 716218 )
    If you point all of them at piece of solder, will it melt? If you point all of them at a match will it ignite?
    • by Anonymous Coward
      Can they, together, be seen bounced off the cloud cover? With more powerful batteried? Could they be arrayed to make a pair of angry red eyes? Could this be centered over a nearby religious institution? Could they, with servos, be used to trace out picutres of the goatse.cx guy in a fashion similar to the goatse.cx guy jack-o-lantern? If someone did that, say..., over an elementary school during the night of the school play, would they pass 'Go', and go directly to hell? And if they did, would that co
    • Re:experiments (Score:5, Interesting)

      by crapulent ( 598941 ) on Thursday November 20, 2003 @06:32AM (#7518445)
      I don't think so. Even if they were putting out the maximum 5mW of power (which they're not) that's still only 0.6 Watts. The smallest and weakest soldering irons out there are probably at least 10 to 20 times that much power, and they'd have a tough time melting anything but very small pads.

      And, even more importantly, it's not going to be very focused. If you look at the spot a laser pointer makes it's more of a blob, the optics on these things are NOT meant to be very accurate. Plus, with 120 of them, there's almost zero chance that they'd all be aimed at exactly the same spot. In order for cutting lasers to be useful they have to be highly focused and concentrated in a very small spot, much like the whole magnifying-glass-starts-fires trick thing.

      I think you'd have a better chance of getting something to light by rubbing sticks together.
    • They're great for doing structured light experiments like this [tinyurl.com].

      Disclaimer: my site.

    • Re:experiments (Score:3, Informative)

      by Matthaeus ( 156071 )
      The whole point of a laser is that all the photons emitted from it are in phase with each other. The photons emitted from one laser are not necessarily in phase with those emitted from another laser. Thus, while you might be able to get .6 watts out of these lasers, it wouldn't be anything near like having a .6 watt laser. And it definately would be too bulky to mount on the head of a friggin' shark.
  • obligatory (Score:5, Funny)

    by Anonymous Coward on Thursday November 20, 2003 @05:15AM (#7518285)
    Get 120 ill-tempered sea bass and a lair. Also Elizabeth Hurley and/or Heather Graham. Actually you could pretty much skip the bass.
  • by nathanh ( 1214 ) on Thursday November 20, 2003 @05:16AM (#7518289) Homepage
    Well, first I'd buy a really big aquarium to hold the 120 sharks...
  • by glassesmonkey ( 684291 ) * on Thursday November 20, 2003 @05:18AM (#7518293) Homepage Journal
    Step 1: Procure 120 sharks Step 2: ..oh nevermind.. too obvious
  • by KDan ( 90353 ) on Thursday November 20, 2003 @05:24AM (#7518313) Homepage
    A method for inducing cats to exercise consists of directing a beam of invisible light produced by a hand-held laser apparatus onto the floor or wall or other opaque surface in the vicinity of the cat, then moving the laser so as to cause the bright pattern of light to move in an irregular way fascinating to cats, and to any other animal with a chase instinct.

    Where will the madness stop??????

    Daniel
    • This is where the madness starts... Mwuahahahah!
    • What's invisible light? I usually find that when I look into a light source that it's highly visible.

      Think I might go and patent the above, but using plain old visible light instead :-)
      • But then the cat would know it was a trick - duh.
    • Of course, the laser pointers in question are most likely red, thus making the wavelength of the beam in the visible spectrum, so have no bearing on the patent. If in doubt, apply a refractive/reflective substance (i.e. fog or smoke) and pass the beam through it. Definitely not invisible.

      Aside from which, $DIETY has prior art, re. the Sun and a Tree.

      Rinse, repeat, watch the animal pant in exhaustion. Loads of fun.

  • by neglige ( 641101 ) on Thursday November 20, 2003 @05:34AM (#7518329)
    and place a speaker nearby. Install a proximity trigger. If triggered, light up all pointer and have the speaker bark "FREEZE! POLICE! PUT DOWN YOUR WEAPON AND LIE ON THE GROUND! [small pause] DON'T EVEN THINK OF IT, PUNK!"

    For a better effect, let each pointer move veeeery slightly. And if you want, you can add a nice gunshot.
    • by Anonymous Coward on Thursday November 20, 2003 @06:16AM (#7518399)
      Funny. No really. The first time some idiot let me use a laser pointer was on the roof of the dorm, at midnight, when the power had gone out. I would just silently point it at people walking to and from the dorm. Then, when that didn't work and they started to run, I'd just shout, "NO USE RUNNING. IT'S A HIGH-POWERED RIFLE."

      Oh well. One person's funny, is another person's terrorist threats. But back then you wouldn't even get written up for crap like that. Of course, that might have been because I gave them someone else's name and room number.
      • Personally, I always preferred the phrase, "Dont run, you'll only die tired".

        It is a little more subtle :)
      • Do that crap around me and you will find a few extra 9mm diameter ventilation holes in you.

        Do it around a cop, they will haul you off to prison, if you survive the surgery.
        • by Anonymous Coward on Thursday November 20, 2003 @07:58PM (#7524469)
          Good luck with that when it's pitch black and I'm behind a waist high concrete edge 100 feet above you.

          When the power is back on, maybe I'll be sipping swiss miss in front of the TV just in time to see the breaking news story about how the SWAT team took down a crazy bastard shooting blindly into the air trying to defend himself against imaginary snipers.

          Like everyone else on the internet you talk tough. But, hey, 'talk': It really is cheap. So knock yourself out.
    • by cei ( 107343 ) on Thursday November 20, 2003 @10:27AM (#7519392) Homepage Journal
      Hell, attach mirrors to the speaker cone and point them at that from different angles. Play music through the speaker and instant light show!
  • Simple, paint the moon red :-)

    http://www.space.com/scienceastronomy/generalscien ce/laser_moon_010810-1.html [space.com]

    you only need about 24880 more
    • by fuzzybunny ( 112938 ) on Thursday November 20, 2003 @06:53AM (#7518507) Homepage Journal

      Astronaut: Houston control, we have a problem. The Russians have painted the moon read.

      Houston: Apollo command, do you have any white paint? Repeat, do you have white paint on board?

      Astronaut: Affirmative, Houston control

      Houston: Apollo command, put a Coca Cola logo on it.

      (runs for cover)
    • "you only need about 24880 more"

      No, with diffusion you'd need a LOT more than that. If memory serves, you'd need millions, and even then you'd likely not see results.
  • Be artistic... (Score:3, Interesting)

    by Zarf ( 5735 ) on Thursday November 20, 2003 @05:39AM (#7518337) Journal
    1. Use the poll thingies that they use in chemistry labs to set up tubes, beakers, and those crazy glass pipes to set up your lazer pointers so that all 120 of them can be mounted and aimed as a giant grid.
    2. Find a way to lock each one in the "on" or "lit" position.
    3. Get a bit-mapped picture of Bob from the Church of the subgenius. Reduce it to a pointalized B&W picture.
    4. Project Bob on to the wall that the laser-pointers are aimed at.
    5. Position each dot to aim at the center of an individual "white" pixel.
    6. Fix the positions of the pointers relative to each other... viola portable projected Bob-head.


    Do "Tux the Penguin" or Bill Gates next if you have lazer pointers left over. If you can't get those chemistry set poles then maybe a bunch of lumber and silly putty would work... Forget the lumber... just use mountains of Silly Putty!
  • Build a 3D imager. Gregg Favalora, the founder of Actuality Systems [actuality-systems.com], did just this as a precursor to his company's 3D imaging systems. It consisted of lasers from laser pointers, a spinning plane, and a microprocessor. The array of lasers would light momentarily to create voxels, 3D pixels, on the plane. Add some well-crafted software and you have 3D monochromatic display. I can't seem to find a image of this on the web, but I can assure you the picture of Homer Simpson's head was unmistakeable.

    Note:

    • Something I've wanted to do. It'd be great if you got some in green and blue as well.
      Mount one pointed at two rotating mirrors, so that the beam scans left-right creating a line, and each such line is scanned up-down. Ie, the left-right mirror needs to rotate something like 500 times faster than the up-down mirror, and that needs to scan at 24 sps. (if you have a 6 sided mirror, that is 4fps -> 240rpm. That means the small mirror would need to spin at 120000rpm! A bigger mirror with more sides is probabl
  • by cyphem ( 609056 ) on Thursday November 20, 2003 @06:10AM (#7518392) Journal
    Just buy 120 sensors which can recognize laser
    light, a ton of wires, a loud electronic horn,
    and a computer to connect them to.

    Then you can build your very own 'I-have-
    something-very-expensive-to-protect'-roo m. Put a
    tux or your favorite CBN-Shrine in the middle and
    place sensors and lasers at the walls crossing
    the room in a wild way.

    Congratulations, the room is now safe from
    intruders. (at least you will hear them if they
    come.)


    cy

    PS: Hey... you could practice to come thru there
    without hitting the beams like in these movies,
    where they try to steal a huge diamond, some
    prototype chips or a very tasty peanut butter
    sandwich. Choose what you prefer to reach...
    • You can make an attraction of this; a room full of this, and people have to try to get through it without starting the alarm.

      You can make the beams visible with some kind of fog, or keep them invisible (they just have to look at the pointers and the sensors), then it would be funny too see those people step over invisible fences and so on :)
    • by EMIce ( 30092 ) on Friday November 21, 2003 @03:50AM (#7526737) Homepage
      I did this once. A cheap radio shack photocell tied to +5 volts via an active output pin on your parallel port, with the other end of the photocell going to an input pin on that same port, will cause that input pin to read 0 when little or no ambient lighting is present. When hit by a red laser pointer the resistance across the photocell is lowered and the voltage at the input pin ramps up above the binary threshold, to more than ~0.8 volt but less than 5 volts. Because of this, reading the input pin from software when the photocell is lit by a laser beam shows a binary value of 1. To avoid false alarms from stray light, I housed the photocell in a sealed, opaque box with a hole in it for the laser beam to enter and hit the photocell.

      A simple C program that reads and writes the memory address of the parallel port can detect, log, and act on these "laser trip" events, doing something as simple as beeping, or as complex as taking a picture and asking for a code. The program should write a 1 to the bit that controls the output pin you are using so that +5 volts appears on it. It should then repeatedly read the input pin you are using. When the input pin transitions from 1 to 0, even for a moment, you know the laser beam has been cut.

      The quick and dirty C code to do parallel port operations under linux can be found at here. [experts-exchange.com] For beginners I suggest you use one of control bits/pins as your output and one of the status bits/pins as your input. The data bits/pins are bi-directional and must be configured for input or output, and using them makes things slightly more complicated. If you want to get really fancy try using the parallel port IRQ to detect the transition from 1 to 0, this should save processing power by avoiding an expensive loop to check the state of the input pin constantly.

      If you need a little more background on the parallel port before diving in, check out this resource [lvr.com]

      Finally, the above description is for a single laser beam. I used a mirror to bounce a single beam around, to get greater coverage, and to provide the effect of multiple beams in the presence of aerosol or powder. You should be able to support thirteen independent laser beams on a single parallel port, using the data bits/pins and the status bits/pins combined.
  • by Anonymous Coward on Thursday November 20, 2003 @06:12AM (#7518395)
    Form the lasers into a grid say 15x8 or 17x7 and set them in some plastic let say ... polyethene resin. And rig them up with a hand held computer and (hand waving) a couple of relays.
    You will then be able to project messages on the people, walls, cars. Insert funny messages here...
  • 3D projector (Score:4, Interesting)

    by bolind ( 33496 ) on Thursday November 20, 2003 @06:24AM (#7518423) Homepage
    OK, remember the dude who put a couple dozen LED's on a spinning arm (think windmill) and triggered them at just the right time, so when the arm span, he'd have graphics or text or whatever in mid-air.

    Place all 120 of them on an arm, but spin it around its own length (think driveshaft) in the middle of a room. If you were able to control them individually (even though they were spinning) you could have whatever graphics you wanted on the walls.

  • UFO (Score:5, Funny)

    by captainkibble ( 725355 ) on Thursday November 20, 2003 @06:33AM (#7518451) Homepage
    Get a huge ballon and a tank of helium. Inflate huge ballon. Attach laser pointers to it turn them all on and let it flaot away. Then put on the local TV news and wait for reports to come in. Extra points in your are near to an airport or airforce base. ;)
  • sell them (Score:5, Funny)

    by !the!bad!fish! ( 704825 ) on Thursday November 20, 2003 @06:36AM (#7518458) Homepage
    Why not sell 119 of them on e-bay and use the proceeds to buy a fat cat.
  • One random idea I had yesterday -- use them at a protest rally.

    Having every protester bring a laser pointer and point it at the source of their ire as they go past could make the point quite well. Particularly if they're just watching silently with banners saying something like "We're watching you" or similar.

    You'd have to make sure that you wouldn't injure the target with that many beams in the same place, of course - would getting 20 of those in the eye at once be harmful?

    And it might not be a good id
    • No, better yet, Bush's next public speaking engagement. Imagine the surprise he'd get when suddenly 120 lasers all point at him(and the fun I'd have watching him dive for it :)
    • by captainkibble ( 725355 ) on Thursday November 20, 2003 @07:07AM (#7518544) Homepage
      Or alternatively take a few friends to watch a protest rally from a nearby building and shine the laser pointers onto the protestors. Might freak a few out if they thought snipers were watching them. Especially effective when they are protesting a high profile person like Bush.
    • Having every protester bring a laser pointer and point it at the source of their ire as they go past could make the point quite well

      Yeah, great idea [bbc.co.uk], get yourself shot.

    • You'd have to make sure that you wouldn't injure the target with that many beams in the same place, of course - would getting 20 of those in the eye at once be harmful?

      Getting one in your eye at once is harmful. Focussed laser light can burn your retina, even low power light such as that.

      however, if you see them at different locations, that means the laser light is focused on different area of the retina. So 20 isn't necessarily an order of magnitude more harmful, it's just 20 times the risk...
  • by (H)elix1 ( 231155 ) <slashdot.helix@nOSPaM.gmail.com> on Thursday November 20, 2003 @06:52AM (#7518502) Homepage Journal
    Take out security cameras in a good chunk of downtown London....

    Laser pointers nicely mess up video camera... It probably won't hurt the camera, but here is a fun read [naimark.net] if you have a bit of time on your hands.
  • by fuzzybunny ( 112938 ) on Thursday November 20, 2003 @07:09AM (#7518550) Homepage Journal

    You will need:

    322,951 crewmen

    Several million tons of quadanium steel

    Approx. 950,000 troopers in cool white plastic uniforms

    One (1) small moon at the outer edges of the known galaxy at which to construct the thing.
    Here are some technical specs [galacticem...tabank.com], and a handy diagram [tiscali.it].

    Basically, you do the following:

    (1) Use all the steel to build this gigantic metal ball, with a dimple on one side. You use a huge rubber band (available at your friendly neighborhood hardware store) to hold the laser pointers together, and put them in the dimple (make sure the batteries are always charged.) Get all your 1.5-odd million crew guys and troops on board, and fire the bitch up.

    (2) ...

    (3)profit!

    Warning: Warranty void in case of attack by swarms of rebel fighters and small foam balls [stanford.edu].

    • Too much of a liability. What would happen to all the independant contractors you'd have to hire if the thing was blown up before it was completed? You'd have the weight of your conscience bearing down on you, plus the outrageous lawsuits that would ensue.

      Personally, that's a job I would pass on. Independant contractors have to choose their jobs wisely.
  • by Chilles ( 79797 )
    Build a giant "Laser" on the moon and call it the "Death Star"
    *cough*ripoff*cough*
    (don't forget to mimic the quotes while telling your good for nothing son about it)
  • Scrolling Message (Score:3, Interesting)

    by bpb213 ( 561569 ) <bpbyrne@@@gmail...com> on Thursday November 20, 2003 @09:13AM (#7518926)
    Hook them up in a grid, all pointing in one direction.
    Make this grid 7 rows high, and 17 columns long.
    Then you have a projectable scrolling display.

    (with of course the right hardware to turn the lasers on / off at the right times.)
  • by His name cannot be s ( 16831 ) on Thursday November 20, 2003 @09:15AM (#7518939) Journal
    For your birthday, we have a plan to write your name into the moon.

  • First find a building with a big flat side to it. Make sure it has no windows and it's late at night. Make a machine that will draw vectors by moving the laser really rapidly that takes some sort of video input. Insert Atari vectors based game like Asteroids or Star Wars. Or you could make a special version of pac-man that goes between the windows of the building if you can't find one without. Make your friends control the ghosts like the upcoming GameCube version and give everyon3 classic 2600 controll
  • Garden (Score:4, Interesting)

    by skinfitz ( 564041 ) on Thursday November 20, 2003 @09:28AM (#7518992) Journal
    Set them up in your garden so that they form a grid with sensors to detect when beams are broken. Write some software to generate a grid reference from this data so that any object breaking the beams can be tracked to it's sector - B6, E2 etc. Draw a diagram of the grid and print it out. Send copies to your friends.

    Output the grid reference to a web page - it should now be relatively easy for your friends to track your exact position in the garden while talking on the phone
  • I'd cause the the biggest case of crotch-dot the world has ever seen!

    "Hey buddy, you better get that checked out. My uncle died of crotch dot." - Chief Wiggum
  • Modulate the laser beam with data and create an ultra-long distance laser data link. Of course ultra-long distance is a relative term... YMMV
  • by Tom7 ( 102298 ) on Thursday November 20, 2003 @10:27AM (#7519395) Homepage Journal
    "Monzy" has a bunch of good games that can be played [monzy.org] (see bottom) when the members of a movie audience have laser pointers. Just make sure you get them back before the movie starts. ;)
  • by Maresi ( 456339 ) on Thursday November 20, 2003 @10:33AM (#7519443) Homepage
    and drive downhill through a foggy town in the dark.

    Go to bed.

    Get up and read the newspaper(s).

    LOL

  • by cgenman ( 325138 ) on Thursday November 20, 2003 @10:51AM (#7519615) Homepage
    Attach about 30 of them to two gloves, and go dancing.

    Attach an AC adapter and mount a row of them above the front door, aiming down.

    Give them away at a local school. The teachers would love that.

    Drill holes into a thick wooden board, mounting the pointers upwards under a sheet of transparent plastic or glass. Sacrifice an audio LED controller or two to synchronize the beams to music. Learn to dance.

    Attach them all to a single trigger, and mount them together with a large amount of tape. Keep in your glovebox. When someone cuts you off, aim at their rear-view mirror.

    Build your own really inefficient 3D scanner.

    Can you say, Flash Mob?

  • by Froggie ( 1154 ) on Thursday November 20, 2003 @11:13AM (#7519808)
    Shine lots of beams across your living room, set up a fog making machine, and see if Catherine Zeta Jones turns up...
  • A bar (Score:5, Funny)

    by splattertrousers ( 35245 ) on Thursday November 20, 2003 @11:32AM (#7520009) Homepage
    Go to a bar with a friend. Both of you walk up to a pretty girl. You tell her, "I have 120 laser pointers and I'm trying to come up with an interesting way to use them."

    The next morning, call your friend and ask him how the girl was in bed.

  • What couldn't you do with 120 lasers?
  • Musical instrument (Score:5, Interesting)

    by cybermace5 ( 446439 ) <g.ryan@macetech.com> on Thursday November 20, 2003 @11:37AM (#7520059) Homepage Journal
    Put them all in a frame, each pointing at a phototransistor, and link to a frequency generator or microcontroller with MIDI output. Now you have a laser harp.

    In fact, here's a very informative website on the subject: The 250 laser harp project [stanford.edu]. Includes links to different projects, schematics, part sources, etc.
    • That's neat. I was actually thinking of how you could construct a visual display of music being played.

      Maybe set up something like a rack of lucite rods and have the lasers to point end-on into them. Have a rod light up when the corresponding note is played, either based on a MIDI file or such, or by depressing the key of a keyboard (which is similar to the laser harp).
  • by Alpha27 ( 211269 ) on Thursday November 20, 2003 @12:17PM (#7520440)
    I may not have spelled the casino's name correctly, but if you know, the casino has a huge water fountain feature in front, programmed by computer to perform a 20 minute show. You could replicate this using the laser lights, some motors to dirct the beams, and build it inside a plexiglass box with smoke to show the laser lights.
  • Posting anonymously? (Score:3, Interesting)

    by breon.halling ( 235909 ) on Thursday November 20, 2003 @12:40PM (#7520667)

    Sorry if this is slightly off-topic, but I'm the submitter of this article, though I did so anonymously. Is it standard Slashdot practice to change the submitter's (anonymous) name? If you'll notice, the article start "lazed-dazed asks: ..." instead of "Anonymous Coward asks: ..."

    Just curious.

  • Aim them all to point at a single spot. Then use it to fry things.
  • I think you should create some sort of device in which these laser pointers are mounted. Then hack together something with which you can change the pattern against the wall at your pleasure. I personally have always wanted a whole wall full of taplights so that I could do just that. It would be hours of family fun. Plus I would see the potential for some pretty good geek time if you could write up some software or whatnot to control the pattern, either through your PC or other device. Enjoy!
  • It's that time of year: give 'em away to one of the Santa charities. Kids love laser pointers.
  • Tetris (Score:3, Interesting)

    by cgenman ( 325138 ) on Thursday November 20, 2003 @02:10PM (#7521547) Homepage
    Buy (used) a TI-85 and an LCD projection filter. Make a 12 x 20 array of closely-packed Lazer pointers.

    Play tetris on the nearest available building.
  • by jdclucidly ( 520630 ) on Thursday November 20, 2003 @03:01PM (#7522141) Homepage
    You could get a large group of people to converge on a scientology meeting. Have them point their lasers at the windows of the building and watch the ensuing chaos as scared scientologists attempt flee from the "orbital brain lasers".
  • by JoeBuck ( 7947 ) on Thursday November 20, 2003 @03:26PM (#7522419) Homepage

    Find 119 friends. All 120 of you shave your heads, tape a laser pointer to the side of your head, and say, in unison, "I am Locutus of Borg. Resistance is futile, you will be assimilated."

  • "hi, my ex-wife left a box of these laser pointers behind and, well, I don't need them and I'd rather have power tools..."

  • IP over laser pointer.

    I'm sure there's already a RFC.
  • Sell them... (Score:3, Insightful)

    by Micah ( 278 ) on Friday November 21, 2003 @09:18AM (#7527438) Homepage Journal
    ...for a few bucks each, and have a few hundred bucks with which to buy a nice quad-proc motherboard and CPUs.
  • by Proudrooster ( 580120 ) on Sunday November 23, 2003 @03:40PM (#7543180) Homepage
    In California it's a felony [hps.org] to aim a laser pointer at an aircraft.

    Laser pointers can blind pilots [faa.gov].

    I would turn them all on at once and aim them at the moon and see if you can get it to explode! Just make sure you don't hit any aircraft.

    Have fun!

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