Simple Entry/Exit Counter using transition of voltages

Discussion in 'Homework Help' started by tophed, Mar 21, 2011.

  1. tophed

    Thread Starter New Member

    Mar 21, 2011
    3
    0
    Hello People, I'm currently doing our homework
    Our teacher gave us this problem and conditions:

    A Simple Entry/Exit Counter
    Entry: Count Up
    Exit: Count Down
    Max. Count: 100
    Min. Count: Zero

    using transition of voltages


    Is there someone who could give me an idea of how to start it? If possible maybe someone can provide me a circuit diagram. It would be a very big help for me.

    Thank you so much people! :D
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    As this is homework, supplying a complete project is not what we are here for. We will help with your project, but you must make the attempt.

    You have to count up and down - that's a job for an up/down counter IC.

    How do you propose to "see" people entering and exiting? How can you tell if they are coming in or going out?
     
  3. tophed

    Thread Starter New Member

    Mar 21, 2011
    3
    0
    our circuit will only be done on a breadboard and not on actual..and i have been googling it but all results are leading n the use of sensors. our professor do not suggest on using sensors..becoz we are not on that topic yet..can you kindly give us any hint on how to do this..?

    thank you! :D:D:D
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    One of the oldest ways to detect the passage of a solid body is with a light source and a photosensitive sensor. With visible light, CdS cells work. With IR, phototransistors work well.

    Googling "sensor" does not produce useful results. Try "light sensor".
     
  5. tophed

    Thread Starter New Member

    Mar 21, 2011
    3
    0
    is there any alternative way than using sensor in entry/exit counter?
    ..how can i CASCADE 74191 counter?

    thanks!!!:)
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    You are trying to count people and display the count. The '191 is a binary counter. You would find life easier using a BCD counter, like the '190. The data sheet will give you valuable information.

    If you want to place switches under floorboards that get pressed down when somebody goes in or out, that might work. How can you tell if they are going in or coming out?
     
  7. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    Are you sure you are supposed to use a sensor? Breadboard circuits tend to be more educational-oriented in learning institutes. Perhaps you could just have two buttons: one for a count-up and one for a count-down.
     
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