Binary to bcd converting problem

Discussion in 'Homework Help' started by KhaledZH, Nov 28, 2018.

  1. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    Hi. I have a project in Measurement class "Temperature sensor". The lecturer told us not to use microcontroller & Arduino so i did it with ADC0804, 74LS47 & 7 segment display.

    my problem is the output of the ADC0804 is binary and i tried to use DM74185a to convert it to bcd i used the circuit in datasheet but it didn't work in proteus and in my circuit and i don't know why.

    if anyone know how to use it please help!
     
  2. dl324

    AAC Fanatic!

    Mar 30, 2015
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    Welcome to AAC!

    You're going to have to give us more information before we can help you. Does the fact that 74185 is unavailable affect your decision to use it?

    Is this homework? Binary to BCD conversion is a common homework question that few have solved because the ones who know how to do it don't come here for help...
     
  3. MrChips

    Moderator

    Oct 2, 2009
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    Moderated: Moved from Digital Circuit Design.
     
  4. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    It's not homework it's a hardware project. 74185 is available and i have 3 ICs of them but it doesn't work with me in my circuit and i connected it like this.
     
  5. dl324

    AAC Fanatic!

    Mar 30, 2015
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    We don't differentiate between homework or school projects. Anything that you'll receive a grade for is considered homework.
    In Proteus or an actual breadboard?
     
  6. absf

    AAC Fanatic!

    Dec 29, 2010
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    Where did you get the 74185 from?
    Hong Kong or Russia?
     
  7. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    Actual breadboard
     
  8. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    In a small shop in Jeddah Saudi Arabia
     
  9. jpanhalt

    Expert

    Jan 18, 2008
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    Can you post your schematic for the ADC0804?
     
  10. absf

    AAC Fanatic!

    Dec 29, 2010
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    Did you connect "G" to GND, Vcc and Gnd to +5V and 0V respectively?
    Like below...

    74185 ckt.PNG
     
  11. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    Yes. And it didn't work
     
  12. dl324

    AAC Fanatic!

    Mar 30, 2015
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    Have you checked the inputs and outputs of each 74185 to verify that they're functioning correctly?

    If you didn't purchase from an authorized distributor, the parts could have been reclaimed or counterfeit. Like I said, those parts are unavailable from reputable electronics suppliers.
     
  13. crutschow

    Expert

    Mar 14, 2008
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    Below is a Binary to BCD conversion circuit using an up/down counter.
    You just increase the number of counters for more digits.
    If you already have a suitable clock, you don't need the multivibrator clock circuit.
    Discussion is here.

    upload_2018-11-29_8-35-23.png
     
  14. jpanhalt

    Expert

    Jan 18, 2008
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    Based on that information, how can we be sure the problem is not at the ADC stage? For example, is the TS using a clock? What is he using for a clock? The datasheet gives options.
     
  15. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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  16. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    I thought of that but even in the proteus it didn't work so the IC isn't the problem, the connection is the problem
     
  17. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    the ADC stage is fine. before i put the LM35 sensor i tried it with Pot and the circuit is working fine the 7 segment gives me the right numbers but in hex.
     
  18. jpanhalt

    Expert

    Jan 18, 2008
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    That is the first mention of your input device. If your test of it is valid, then it seems you have shown that the ADC and BCD functions work fine and virtually all of the posts up to this point are not related to the real problem.

    In response to post #5, you state this is not a Proteus simulation but rather an actual breadboard. Yet, you give a Proteus design. Was your validation test with a pot done in Proteus or on your current breadboard?

    Now, how about some detail. What voltage did you present with the pot? Is that the same voltage range produced by the LM35? How do you have the LM35 attached to the ADC?
     
  19. KhaledZH

    Thread Starter New Member

    Oct 26, 2018
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    This is my breadboard. The problem is that the number in hex and i want it in decimal. I tried DM74185a but it didn't work with me is it clear now?
     
  20. crutschow

    Expert

    Mar 14, 2008
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    If the DM74185a doesn't work and, since it's an obsolete device, you may need to try a different circuit, such as the one in post #13.
     
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