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5 mW Laser <$5 — Parallax Forums

5 mW Laser <$5

ercoerco Posts: 20,260
edited 2010-07-07 03:45 in General Discussion
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330447263612

Got laser?

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·"If you build it, they will come."

Comments

  • LeonLeon Posts: 7,620
    edited 2010-07-06 15:48
    I've got one which says max output < 5 mW, whatever that means. Mine uses two AAA cells, as well, and is very solidly made. I'm sure I paid more than $5 for it, though. I sometimes use it to amuse the cat.

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    Leon Heller
    Amateur radio callsign: G1HSM
  • wjsteelewjsteele Posts: 697
    edited 2010-07-06 18:20
    I'm not sure I'd trust it... it says <5mW which is "LESS than 5 mW." That could mean anything... heck a standard .5mW Laser Pointer fullfills that and they're a dime a dozen!

    I have "laser pointers" that I used in the development of our Heads Up Display that are ~200mW. wink.gif They make a "barely" visible daylight readable display. We actually use 3 of them for daylight use, RGB and another that is Infrared, for our scanning system.

    We prototyped everything with low power units in the .5 to 5mW range, depending on color, etc.

    Bill
  • K2K2 Posts: 693
    edited 2010-07-06 19:37
    Oddly enough, I ordered this same product from the same seller just last week. The low price and the use of AAA cells rather than button cells are the two features that most appealed to me. I look forward to it coming.

    The same day I also ordered a green laser pointer for a few bucks more. This strikes me as amazing... A green semiconductor laser is much more complicated: 808nm IR lasers pump a neodymium doped yttrium orthovanadate crystal that lazes as 1064nm. This is then frequency-doubled by a non-linear optical material called potassium titanyl phosphate, et voila, 532nm green light. And, apparently you can get all that for about six bucks. Time will tell.

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    The early bird gets the worm but the second mouse gets the cheese.
  • localrogerlocalroger Posts: 3,452
    edited 2010-07-07 02:07
    I have a 1.5 mW laser I got surplus. Of course I got it back in 1988 so it needs 110 VAC for its HV power supply, the tube is about a foot long and makes a pretty and bright neon glow as it operates, and since the rear reflector isn't perfect there is a faint but detectable back beam that comes out the back of the He-Ne tube. I mounted it in a square acrylic tube so its wastage could be appreciated, but using it as a pointer would be awkward.

    It does work quite well as the light source for multiple-tilted-rotating-mirror spirograph arrangements and for making quartz crystals glow from within by aiming the beam at their milky/translucent parts.
  • Peter KG6LSEPeter KG6LSE Posts: 1,383
    edited 2010-07-07 02:49
    They have VERY good beam quality . diodes have still not replaced them in Labs as the beam of a Diode can have a ton of nasty TEM modes that can be advrse to a lab .....I love my HeNe's ......... but my 808nM 5W diode is more fun LOLs

    Peter KG6LSE

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    "Carpe Ducktum" "seize the tape!!"
    peterthethinker.com/tesla/Venom/Venom.html
    Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway. —Tanenbaum, Andrew S.
    LOL
  • ercoerco Posts: 20,260
    edited 2010-07-07 03:06
    I bought this one:
    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290442256271&ssPageName=ADME:B:EOIBSA:US:1123
    a while back for $1.76 from China, which looks similar. It is definitely brighter than button-cell units, but per Bill's post, doesn't mean it's rated at 5 mW, just less than 5. It's plenty strong for my needs, though, as a photon exciter for my Death Ray.

    Oops, there goes my secret plan!

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    ·"If you build it, they will come."
  • LeonLeon Posts: 7,620
    edited 2010-07-07 03:45
    A friend of mine bought a He-Ne laser when they were very new. He lived in an isolated cottage in Wales and used to amuse himself by aiming it at walkers a 1/4 mile or so away, and watch their reactions to it.

    When I worked at Xerox Research (UK) one of the physicists there got a new high-power laser and tested it by burning the paint off the lab walls. I don't think he bothered with eye protection, people weren't all that concerned with laser safety in those days.

    I tried my pointer out on the Herring Gulls nesting on my balcony. One of the adults and one of the chicks were scared by it, the other chick was fascinated by it and tracked the spot visually, and the other adult kept pecking at the spot.

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    Leon Heller
    Amateur radio callsign: G1HSM

    Post Edited (Leon) : 7/7/2010 3:55:27 AM GMT
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