long distance sensor

Discussion in 'General Electronics Chat' started by infidelboy, Aug 8, 2010.

  1. infidelboy

    Thread Starter New Member

    Aug 8, 2010
    6
    0
    i am looking for a transmitter-receiver pair that can work upto 10 to 15 mt.

    help plz..
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Just to confirm, the range you need is 10 to 15 meters?

    hgmjr
     
  3. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    If it's meters you're in, if it's miles you'll need something powerful enough tht you'd need a license to operate the transmitter portion.

    Then again it's a wonder what a good antenna setup can do with a sensitive receiver.

    What are you intending to transmit and is thre a preferrred frequency range?

    I'm pretty darn good with antennas and recently designed a blockbuster mast mount preamp circuit that provides at least 20 dB gain at less than 1 dB of noise. I designed it for the commercial FM radio band but could be adapted to other frequencies, gain could be increased as well. It matches up to a directional antenna that provides 10 dB of gian on its own.

    There are also a number of Chinese sellers on eBay that have some pretty inexpesive pre-made modules, all depends on what you're trying to do.
     
  4. gootee

    Senior Member

    Apr 24, 2007
    447
    50
    What is the purpose of the transmissions? And in what nation will they be used?
     
  5. kingdano

    Member

    Apr 14, 2010
    377
    19
    ultrasonic rage finders are well suited for this application, provided that you are not passing through any incompatible media or reflecting off of an incompatible surface.

    i recently looked into sensors - here are some good manufacturers

    www.sensortechnics.com
    www.stevenengineering.com
    www.baumer.com

    an applications person there will easily be able to guide you to the correct fit.
     
  6. sage.radachowsky

    Member

    May 11, 2010
    241
    38
    I've worked on a wireless system in Nepal that worked over 34 km with an off-the-shelf WiFi access point, using good 29 dBi parabolic grid antennas and a receiver that had good senstivity.

    It comes down to the math of the transmit power, a clear Fresnel zone, low interference, and good receive sensitvity. The antennas can then be chosen. Note that high gain antennas need careful aiming.

    Here's one of those antennas on the mountaintop.
     
  7. infidelboy

    Thread Starter New Member

    Aug 8, 2010
    6
    0
    The motive for the sensor is to

    1. sense a robot within range of around 20 meters..
    2. use a fixed frequency to detect it.
    3. should detect the robot in only limited field.. means all the usual sensors transmit wave in spherical wavefront but i need something like ir sensor or something that will have a conical or semi-spherical waveform that would help me in not detecting the other robots within the range of 20 mt... because all the robots are operated at same frequency... but the direction of conical waveform should decide which robot to drive.
     
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