need help with this circuit

Discussion in 'The Projects Forum' started by KMK, May 25, 2010.

  1. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    i have designed this simple circuit using 555 timer & 4011 nana gate chip. the circuit is designed to use IR remote sensors to switch the output of the 555 bistable function so the output can go high & low onan IR pulse.
    however the problem is that the out put of 555 remains in an on position. Normally, it flashes when it recives an IR pulse. sometimes it goes to low outpot (max upto abt 2 min) & then automatically switches to high. also the light from other sources in the house seems to be affecting this behaviour. can any pls help me with this so that it work properly??
    here is the circuit diagram. & the Vcc is 3V, not 4.5 as mentioned in the diagram.
    thanks.

    P.S. this is designed on a bread board.
     
    Last edited: May 25, 2010
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Can you post a schematic?
    That will make things more than the many words.

    Bertus
     
  3. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    unable to upload the image.possibly can email it.
     
  4. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    You can upload an image using the manage attachments button:


    Bertus
     
  5. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    let me try. the problem possibly is the size is 380 Kb
     
  6. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Are you trying to upload a .bmp?
    Those are very large.
    Try to save it as .png.
    That is a lossless compression method.

    Bertus
     
  7. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    isn't alowing me to upload the file to an album eiher. directly gives me 'IE cannot display this page' error for both the uploads. & now I was trying a 130 Kb file. possible issue with IE or the antivirus software.
     
  8. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    also a i have said, the IR sensors seem to be sensitive to visible light, as the circuit seems to work when there is light in the room, but changes to high auto high output once the lights are turned off.can you explain me that?
     
  9. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    no luck in uploading picture.
     
  10. bertus

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  11. SgtWookie

    Expert

    Jul 17, 2007
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    What is the filename's extension?

    You could always use a .zip utility, and then upload it.
     
  12. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    have tried that even. that too dosent work. any other suggessions???
     
  13. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    even a zip file dosent work
     
  14. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    hi Bertus, I've finally got the picture
    [​IMG]
     
  15. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    now can any one help me figure the solution out??
     
  16. SgtWookie

    Expert

    Jul 17, 2007
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    Nothing about the "IR Remote Sensor" other than it's somehow wired in there?

    Do you have a datasheet for the sensor? Manufacturer's part number?

    Are those both IR sensors on the left?

    It looks like you have the outputs of NAND gates wired together with the outputs of the IR receivers. This is a no-no. You can only wire outputs together if they are both open-collector (or open drain) and current is supplied by another part of the circuit.
     
  17. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Here is the functional diagram of the NE555:

    [​IMG]


    Pin 6 of the NE555 is undefined at the moment.
    Try it with pin 6 tied to ground.

    Bertus
     
  18. SgtWookie

    Expert

    Jul 17, 2007
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    Bertus,
    Our O.P. DOES have pin 6 of the 555 connected. Unfortunately, it has the output of a NAND gate as well as the output of an IR sensor connected to it. Two outputs connected together = trouble.

    Same thing with pin 2 of the 555; a NAND output and an IR output are connected together to pin 2. More trouble.

    Since there is no information on the IR sensors posted, it will be difficult to suggest a course of corrective action.

    Pins 4 and 5 of the 555 are not connected, but it should still function that way.
     
  19. KMK

    Thread Starter Active Member

    Feb 11, 2010
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    actually, the ping 6 is grounded, forgot to update that in the diagram. also there is no part # as such for the ir sensors, nothing mentioned on them. also the idea is to use the gates to turn off the dupply to one of the sensors when the other is active & the out put of the sensors is given to pins 2 & 4 to ses or reset the 555. also as is said earlier, it seems to be working fine, when there is light in room. as soon as the light is turned off, it goes to kind of auto on position. also if the sensors as disconnected & used one at a time, they seem to perform thei function, ie. one will turn the output on & the other will turn of. but when both are connected, the output goes low for some time & the comes high automatically. what could be the reason for this?
     
  20. SgtWookie

    Expert

    Jul 17, 2007
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    You can supply no information for the IR sensors, so you want for us to make guesses?
     
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