disk readers

Discussion in 'General Electronics Chat' started by caracadon, Jul 4, 2011.

  1. caracadon

    Thread Starter New Member

    Jun 28, 2011
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    [​IMG]

    Trying to learn and want to know what the three items in the image are.

    The one on the left is from a raid system. The other two are from CD ROM drives

    TIA
     
  2. #12

    Expert

    Nov 30, 2010
    16,247
    6,744
    Those things carry the reading device across the face of the information disk. It looks to me that they are all optical types (they use light, not magnetism).
     
  3. caracadon

    Thread Starter New Member

    Jun 28, 2011
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    Ok, then the next question is are they laser?
     
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
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    Almost certainly, and if functional they may present a risk of permanently damaging someone's eyesight, yours for instance. Perhaps best not to meddle...
     
  5. #12

    Expert

    Nov 30, 2010
    16,247
    6,744
    Adjuster handled it so I deleted.
     
  6. caracadon

    Thread Starter New Member

    Jun 28, 2011
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    Hmmm... Trick is don't stare down the barrel of even an unloaded gun. :p
     
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The light emitted by lasers from CD/DVD drives is invisible, which makes them more dangerous - as you can't tell when they are emitting light. Those which are capable of writing to CD's/DVD's will cause harm if used improperly.
     
  8. caracadon

    Thread Starter New Member

    Jun 28, 2011
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    Let's see, which is safer: stay home spring break or actually take 95 south to Ft. Lauderdale? I guess from Orlando I would have to figure which is the absolute safest way to get to I95 first?

    I very much appreciate the concern. However, just imagine Horace Greeley saying 'Don't go west young man, you can starve, freeze, die; mountains and valleys and dangers oh my!' :eek:

    So, the question is being begged, what is the safest way to learn how to hack the laser into an interesting but learning project? ;)

    TIA
     
  9. BillB3857

    Senior Member

    Feb 28, 2009
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    There is a big difference in exploring the unknown and being warned about what is known! More of Darwin at work.
     
  10. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
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    I agree; you should hack if you want. Just be willing to acknowledge there can be invisible radiation that might harm you. If you avoid looking into the source, you should be fine. Besides, those optics all have converging lenses with short focal lengths, so it's likely that any beam you would look into would be substantially diverging; I'd imagine the irradiance (power per unit area) would be quite small and harmless unless you got your eye up near the lens. Of course, the only way to establish this for sure is to ask the designer or measure it.

    Your first task is to find something that could respond to the beam. I would look for an IR photodiode. Then you have to figure out how to turn the laser on and what voltage/current it should be run at. This will probably take some fiddling and web searching to find if others have done similar stuff. Note there are optical coatings that can fluoresce under IR irradiation and emit in the visible; this could be handy to see if you're getting output.

    I have a spectroradiometer that can measure optical spectra from 190 to 850 nm. If you want to send me the device with some connections for the power already installed and the voltage/current to apply (so I don't have to do any fiddling), I'd be happy to measure the spectrum for you (it only takes about a minute). I could also make a semiquantitative measurement of the output power. If you want the thing back, you'd also need to included a SASE or equivalent so I could just put it in the package and stick it in the mailbox (i.e., if I have to go to the post office or go find postage, the thing goes into the dumpster instead).
     
  11. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
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