14 Comments

  1. December 31, 2010 at 6:47 am

    vikas

    u did a gr8 job

    Reply
  2. October 3, 2011 at 7:29 pm

    onyango

    nice project

    Reply
  3. October 25, 2011 at 3:50 am

    alan

    nice project….i also did it and it was awesome only i had to look out for a dark place as the ldr sensitivity was a slight of a problem.

    Reply
    1. October 16, 2012 at 9:31 pm

      SHRIKANT VERMA

      About of all components are used in object counter used in LDR and Calculator

      Reply
  4. December 19, 2012 at 5:52 pm

    sgvinoth

    i done this project.i realy got good o/p.

    Reply
  5. March 10, 2013 at 4:31 am

    Dep

    What can I use instead of the BD139 Transistor??

    Reply
    1. March 10, 2013 at 8:42 am

      Sagar Sapkota

      You can use any other transistor that can drive the relay.

      Reply
      1. March 10, 2013 at 9:04 pm

        Dep

        So something like SL100 or BC 337 would work?

        Reply
  6. October 25, 2013 at 5:04 pm

    NANCY JANI

    Very good idea and project..i did it as my 3 semester project…but sensitivity is little bit problematic.

    Reply
  7. November 24, 2013 at 5:08 pm

    SAM

    i have not found any such caculator which has to work as counter. what can i do to use calculator as counter ?

    Reply
    1. November 24, 2013 at 5:09 pm

      SAM

      plz rep asp

      Reply
  8. May 28, 2014 at 11:06 am

    rken

    how to disable auto power off feature in an electronic calculator because most of the calculators nowadays are electronic….I am hoping for your response…thank you in advance

    Reply
  9. July 30, 2014 at 3:36 am

    Anushka

    Can i replace led & ldr with IR light & IR sensor?

    Reply
  10. October 30, 2014 at 8:37 am

    sachin

    You said that in the calculator we have to press “=” sign after pressing 1 then in normal calculator wlif do this thing we didn’t need any circuit,,,,,,,

    Reply

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