+ Post New Thread
Results 1 to 6 of 6
  1. #1
    Full Member level 2
    Points: 1,623, Level: 9

    Join Date
    Mar 2012
    Posts
    140
    Helped
    4 / 4
    Points
    1,623
    Level
    9

    How to determine the signal strength of the IR transmitter

    hi to all,
    i had designed the through beam sensor by using of the IR transmitter and IR Receiver LED. Its working quite properly. My doubt is how to find the signal strength of the IR tranmsitter Led, without receiver. By the use of receiver i can determine the distance. but not able to find the strength. If i vary the Forward voltage of the IR Transmitter, distance getting increased, while decrease the forward voltage, distance also getting reduced.

    Kindly tell me how to determine the strength of the TRANSMITTER?
    Thanks in advance,
    anboli

    •   Alt25th April 2014, 07:16

      advertising

        
       

  2. #2
    Advanced Member level 5
    Points: 25,337, Level: 38

    Join Date
    Dec 2010
    Location
    Southampton and holiday cottage in Wensleydale (UK)
    Posts
    4,863
    Helped
    1312 / 1312
    Points
    25,337
    Level
    38

    Re: How to determine the signal strength of the IR transmitter

    Do you mean the peak power of the infra red? Measure the power going into the diode, look up the manufacturers spec. Compensate for any focussing optics and you have your answer.
    Frank



    •   Alt25th April 2014, 20:21

      advertising

        
       

  3. #3
    Member level 1
    Points: 846, Level: 6

    Join Date
    Oct 2013
    Posts
    37
    Helped
    0 / 0
    Points
    846
    Level
    6

    Re: How to determine the signal strength of the IR transmitter

    You can check the specs of the IR Transmitter LED from the data sheet which will give you some information about its dissipation of IR for along with the distance.this might help you....



    •   Alt25th April 2014, 20:49

      advertising

        
       

  4. #4
    Full Member level 2
    Points: 1,623, Level: 9

    Join Date
    Mar 2012
    Posts
    140
    Helped
    4 / 4
    Points
    1,623
    Level
    9

    Re: How to determine the signal strength of the IR transmitter

    in the datasheet they given the wavelength 950nm and degree as +or- 15degree..
    http://www.vishay.com/docs/81055/tsus520.pdf

    this is the IR transmitter which im using..



  5. #5
    Super Moderator
    Points: 239,566, Level: 100
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    41,505
    Helped
    12663 / 12663
    Points
    239,566
    Level
    100

    Re: How to determine the signal strength of the IR transmitter

    Figure 5 and Figure 6 do answer your question.



    •   Alt26th April 2014, 09:42

      advertising

        
       

  6. #6
    Member level 1
    Points: 846, Level: 6

    Join Date
    Oct 2013
    Posts
    37
    Helped
    0 / 0
    Points
    846
    Level
    6

    Re: How to determine the signal strength of the IR transmitter

    Fig 5 and 6 give you a relationship for your requirement as indicted by FvM. If you want to calculate the signal strength at some distance from transmitting LED, you can estimated it with radar equation.... but IR is not same as Microwave... IR fades away quicker than microwave



--[[ ]]--