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I am sick of lasers.

Discussion in 'LEDs and Optoelectronics' started by eptheta, Nov 20, 2010.

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  1. eptheta

    eptheta

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    Dec 20, 2009
    I am sick of using lasers and optical sensors to create detector circuits.
    The laser beam is cut, the output is generated. That is the standard procedure.

    Is there any other type of transceiver device that I can use for applications like these ?
    Perhaps ultrasonic transceivers ? Or IR ? Does anyone have any experience with them ?

    From what I know, IR spreads radially from its source so it won't be accurate for applications where I need a single plane to be the sensing area.

    Thanks.
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Passive Infra-red detectors are another (very different) sensor.

    IR is just light. You can have IR LEDs and IR lasers the same way that you can have visible LEDs and lasers. In fact, if you have a green laser, you almost certainly have an IR laser (because green semiconductor lasers are not green).

    There are also several types of ultrasonic sensor. One is ultrasonic "radar". This was used in early Polaroid cameras. I believe that glass break detectors are a form of passive ultrasonic sensor.

    Google "alarm sensors" for lots of information on various alternatives.
     
  3. barathbushan

    barathbushan

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    Sep 26, 2009
    im new to lasers , can you guys explain how much would a laser system cost , and would it require high voltages .
    thanks
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Lasers cost almost nothing. You can pick them up for about a dollar or so.

    Semiconductor lasers require about 3 to 5 volts.
     
  5. barathbushan

    barathbushan

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    Sep 26, 2009
  6. eptheta

    eptheta

    188
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    Dec 20, 2009
    Thanks for the info.
    To be more specific, using laser sensors in broad daylight is a painful task... As accurate as it may be, it is still annoying to set it up.

    From an 'ease of setting up' point of view, and not an accurate/efficient POV, which system of detectors should I use ?

    In all cases, It would probably be equally difficult to align the detector with the source.... and the sun ruins it for optical systems.

    The entire system (assuming a simple alarm triggering mechanism) will cost you less than Rs.50. The accessories to that (alarms, buzzers, LEDs, etc) will raise the cost to a maximum of Rs.150 (or a bit more if you use microcontrollers...)
    So basically, lasers are cheap and very functional.

    As steve said, the voltages are rather low. However, in lamington road, the fellow tried to sell me a Rs.190 laser which runs on 12V. It is probably way cooler than the cheap toy lasers that you find in stores, but for any hobbyist application, the cheap ones are more than enough...

    EDIT: Oh my god 400$ lasers. Unless you wanted to create a death ray, I'd suggest you stick to the other ones...
     
  7. barathbushan

    barathbushan

    223
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    Sep 26, 2009
    Thanks for the info guys , now i'm beginning to think lasers are nice !!
     
  8. eptheta

    eptheta

    188
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    Dec 20, 2009
    Only for the first 5 projects or so, then you develop an aversion towards them... I've used them:
    - for getting angular frequencies of model helicopter blades
    - for measuring relative opacity of some liquids (it didn't work out though)
    - instead of finishing line in a race to record track time

    Now I don't like them for some reason. Lasers just seem to hard to aim...

    If only I was Janeway cutting off a programmable area and generating outputs while walking through a Borg forcefield...
    [​IMG]

    A nice simple plane to work with instead of a hard-to-aim beam...
     
  9. KMoffett

    KMoffett

    723
    75
    Jan 21, 2009
    And you think the Borgs didn't complain about all the hassle of setting that up. ;)
    What you need to do is to purchase a pre-aligned "laser curtain"...but then you have to pay for the hassle of the manufacture aligning them. :eek:

    Ken
     
    Last edited: Nov 20, 2010
  10. eptheta

    eptheta

    188
    0
    Dec 20, 2009
    Other than physical means, is there a way to get sensors to detect only in a single plane ?

    PIR sensors seem apt. Detect body heat and generate outputs, but the proximity needed may be a problem for distance applications. Also, in daylight, I'm not sure IR would be such a good idea....

    Do you think Ultrasonic proximity detectors are a good idea ? Have you worked with them before ?

    Now if i got 2 huge plates charged up and put a guy in the middle then I could make a capacitive proximity sensor..:D
     
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