how to check seven segment working or not using sensors?

Discussion in 'General Electronics Chat' started by Nanda Kumar 1, Aug 28, 2016.

  1. Nanda Kumar 1

    Thread Starter Member

    Aug 25, 2016
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    Hi every one.
    Is there any chances to check the seven segment working or not ,with any sensor ?
     
  2. BR-549

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    Sep 22, 2013
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    I would suggest starting with the datasheet.
     
  3. dl324

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    Mar 30, 2015
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    You could use the diode check function available on many DVMs.
     
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    7-segment? LED, LCD, incandescent, fluorescent? Other?
     
  5. Nanda Kumar 1

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    Aug 25, 2016
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    7 segment .
     
  6. GopherT

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    Yes, you said that in the original post. What kind of 7-segment display. LCD, LED, ...
     
  7. Nanda Kumar 1

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    Aug 25, 2016
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    With out using 7 segment terminals points i want to check the working or not based on the each segment light(a,b,c,d,e,f,g ) .
     
  8. Nanda Kumar 1

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    Aug 25, 2016
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    LED
     
  9. GopherT

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    Both are 7-segment but very different methods are needed to test.

    image.jpg
     
  10. Nanda Kumar 1

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    Aug 25, 2016
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  11. GopherT

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    @Nanda Kumar 1
    Connect a 1k ohm resistor to a 9V battery and then connect a black wire to the battery (-) and a red wire to the end of the resistor that is NOT connected to the battery.

    Then touch red and black wires to two pins of the 7-segment display. Connect every combination. LEDs have a polarity so they will not light up if the red and black wires are connected "backwards" so you need to test every combination in both possible polarities.

    This will light only in segment at a time.

    How many digits is your display and how many pins?
     
  12. Nanda Kumar 1

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    Aug 25, 2016
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    @GopherT thank you for u r clear explanation but i dont want that type i want check each segment with any sensor like LDR .
     
  13. DickCappels

    Moderator

    Aug 21, 2008
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    Drive each segment according to GopherT in post #8. Take 8 phototransisotrs, each one pointing to one segment plus the decimal point if that exists. You can then "And" the outputs of the phototransistors such that you only get a true output when all segments light.

    You can also do that with a video camera but it would be more difficult.
     
    Nanda Kumar 1 likes this.
  14. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Measure the current to each LED; a faulty LED is likely to draw significantly more or less current than a working one. By measuring the current in the common line it would be possible to check all the segments either together or individually.
     
  15. dl324

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    Mar 30, 2015
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    Another option is to use one optical sensor and turn on each LED separately. Position the sensor so it can "see" all segments, or use a light pipe to redirect light.
     
  16. Nanda Kumar 1

    Thread Starter Member

    Aug 25, 2016
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    @d1324 i want to check all segments in one time
     
  17. Nanda Kumar 1

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    Aug 25, 2016
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    Thank you i will try this
     
  18. dannyf

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    Sep 13, 2015
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    Hire someone who knows how to do it and let him do it for you. No sensor involved at all.
     
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  19. hp1729

    Well-Known Member

    Nov 23, 2015
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    ???
    In actual operation or at the bench not connected? Single digit or multiple digit?
    What are you trying to confirm? Forward voltage? brightness?
     
    Last edited: Aug 29, 2016
  20. Nanda Kumar 1

    Thread Starter Member

    Aug 25, 2016
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    i want to check multiple digits at a time like (a ,b,c,d,e,f,g pins).And Brightness
     
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