I need help in figuring out the problem with controlling some seven segment displays.

Discussion in 'The Projects Forum' started by Sabbih Shah, Dec 10, 2014.

  1. Sabbih Shah

    Thread Starter New Member

    Dec 10, 2014
    I am making a control system as my 2nd semester project. The main feature of this system are:
    1. It can control 4 processes.
    2. At a time only 1 process should run.
    3. There is a common reset for all processes.
    4. There would be 7seg display that counts how many times each process has been completed.
    5. The process are high or turned on for a certain time after which they turn off.6.
    6. There are also 7 seg displays that show time each process is taking.
    we are not alowed to use microcontrollers or any ic that needs programming.
    So far I have managed to meet almost all requirements but i am having some trouble in a few things.
    I have used 555 timer as monostable to set processes high for a certain time(one 555 timer for each process sot total of 4 555 timers) and also i have used zener diodes to control the other 555 timer so that only one process runs at a time.
    I have used another 555 timer in astable mode for each process to show time for each process. the monostable 555 controls the astable 555 timer. NOw here is the trouble i am having the 7seg i attached to the astable 555 starts the count from 1 not 0 cant figure out how to start it from 0. I have used proteus to make this circuit. I have attached the complete circuit also the circuit related to my problem seprately.
    Red led always glows showing that process is on standby and yellow led means that process is in progress.
    Also i need suggestions on how to add a buzzer so that whenever a process is completed the buzzer makes a sound. I tried by using not gate at the 555 monostable timer output but by doing this the buzzer makes sound when no process is even happening.
    Also i need sugestions on if i can run the 7 seg backwards like for example i set 555 mono timer time period to 60sec and i set the astable 555 time period to 1 sec is there a way so that i can preset 60 sec on 7seg and count it backwards.
    I have used 4026 decoder and common cathode seven segments.
    Please view the complete circuit and tell me of any way so that i can shorten my circuit.
    Please forgive me for my bad english.
  2. absf

    Senior Member

    Dec 29, 2010
    I am not able to open your proteus 8 file. Instead, can you display your schematic in PNG format so you can get more help?

  3. crutschow


    Mar 14, 2008
    Yes, few of us have Proteus.
    And your .zip file gives me an error saying it is invalid.
  4. Sabbih Shah

    Thread Starter New Member

    Dec 10, 2014
    cct after simulation.png cct before simulation.png cct to control 2 processes.png complete cct.png
    the files cct before and after simulation are for the problem i am having with 7seg starting from 1 not 0. Also in this cct i want to start the seven seg backwards. And other two are of complete cct and incomplete cct.
    The file named cct to control two processes contains incomplete cct for two processes and i am having trouble in adding buzzer in this cct.