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Automatic Room light Controller with Visitor Counter (AT89S52)

Discussion in 'Doubts in My Projects' started by Binu, Jun 2, 2007.

  1. ucpatnaik

    ucpatnaik New Member

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    When there is no obstruction the 38 KHz IR light generated by the 555 being beamed on the TOSP,the output of the same remains low which results in switching transistors Q5 & Q4 open to cause pin 2 of 555 high thus pin pin 3 of 555 is low,meaning the LED connected at its output as available on the PCB (not shown in your ckt)not glowing,Thus pin 1 & 2 of MC are also low.
    How do you state on the above that when no obstruction then pin 3 of 555 is high? Your code also asumes that while pin 1 & 2 of MC goes low from high it shall do the counting.You might be confusing it with LDR sensor which makes your statement valid.But the ckt uses TOSP now.
    Patnaik
  2. ucpatnaik

    ucpatnaik New Member

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    We adjusted our hardware so that when no obstruction then 555 pin 3 remains high ab it goes low only when there is an obstruction.Even then neither the 7 seg display comes nor the relay driving works after 99 interruptions.
  3. Binu

    Binu Administrator

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    At normal time when the IR falls on the sensors then the IC555 output is on High level. and if the sensor was interrupted then the microcontroller will start counting.
    The display use the multiplexing technique, and it will work fine.
    The relay will be activated when the count is greater than zero.

    If you really think that the code is wrong please check it with the 8051 simulator from www.frontline-electronics.com which support multiplexed displays.

    J.Binu
    Click here to Assemble your 8051 Codes online
  4. ucpatnaik

    ucpatnaik New Member

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    "At normal time when the IR falls on the sensors then the IC555 output is on High level."

    The above statement does not tally with the circuit you have given.Please I request go through the circuit. In normal situation, the 555 output is low as I have clearly explained above.How does the output of 555 remain high while
    pin 2 of 555 is high? Request please recheck.You might have tried the circuit with some other sensor and not on the TOSP .This I am dead sure.Thus What you are mentioning repeatedly shall hold good for a LDR used in place of TOSP.I hope you shall appreciate that TOSP output goes low while IR falls on it and its a must & no argument over it please.The circuit asumes TOSP output as high while IR falls on it.This is wrong .Infact while TOSP output is low the Q4 and Q5 is off meaning its collector high.Thus pin 2 of 555 is high that causes pin 3 low.If you disagree with this basic fundamental theory of 555 & TOSP please let me have your comments.I have high respect for your knowledge so please try to rectify the projects as many are trying your circuits who are likely to get frusteted.
    Patnaik
  5. ucpatnaik

    ucpatnaik New Member

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    your code is perfectly ok but the way you explain in not in line with the ckt operation
  6. ucpatnaik

    ucpatnaik New Member

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    I would suggest for all those who would like to try this ckt but want to have good illumination of the 7 seg LED pls connect 330 ohms 7 nos in series to the port pins rather than connecting them directly.But you have to eliminete the collector resistors of the multiplexing transistors and connect directly to the common anode plus pin directly
  7. Binu

    Binu Administrator

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    How did the seven segment displays works now, Do you change anything in the circuit, please post it here. i have done this project before 4years, thats'y i cant explain it more briefy. Please give out the explanation here little briefly.

    J.Binu
    Click here to Assemble your 8051 Codes online
  8. ucpatnaik

    ucpatnaik New Member

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    uniformly brighter now as every segment is with separate resistor.As against only one resistor in series with the common anode affecting illumination level for digits like 8,0 where many segments are on (compared to 1 )that results in larger voltage drop across the series resistor
  9. Binu

    Binu Administrator

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  10. Binu

    Binu Administrator

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    The code can be easily rewritten in C language. Go through the full forum topic to understand the project.
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