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[need help] Serial Communication via Infrared

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by v0xyzzz, Nov 21, 2006.

  1. v0xyzzz

    v0xyzzz New Member

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    can anyone help to solve this problem?
    I'm building a serial communication with IR transmitter-receiver, but the maximum speed is only 2400bps. I need to speed up the transfer rate... Any solution? this is the schematic..

    thanks for the help..
     

    Attached Files:

  2. tunedwolf

    tunedwolf Well-Known Member

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    use a pair of IRDA modules :)
     
  3. akg

    akg New Member

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    i assume the 2400 limit you found is by experimentation , i think your first bottle neck is the modulated ir receiver the tsop .
     
  4. dave

    Dave New Member

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  5. Sceadwian

    Sceadwian Banned

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    Modulate the IR transmit and decode the IR reception yourself. If you're close enough you can basically make a close coupled opto-coupler, which is capable of some pretty high baud rates compareable even to a local interconnect.. As you move away and add noise from the surrounding environment maximum baud rate will degrade obviously but you have to determine for yourself in your application if IR is the right choice, and at what distance it will be useable.
     
    Last edited: Nov 22, 2006
  6. v0xyzzz

    v0xyzzz New Member

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    i guess you're right. I've studied the TSOP datasheet. it say that the receiver should receive 10 burst minimum for every bit. When i used 2400 baud rate, TSOP receives 15 burst, but when i used 4800 it drops to 7 burst (by calculation)..
    thanks for any help..
     
  7. v0xyzzz

    v0xyzzz New Member

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    I have another "bugs".. It seems that the data sent by the IR led, reflected to the TSOP at the same side.... second bugs is that the distance is only about 10-15 cm... (i'm sorry, i don't use inch).. Does anyone here, can help me with the better circuit?
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Install a barrier between your IR LED and the TSOP receiver for isolation.

    Your range is too short. It should go 10m or farther. Something is connected backwards.
     
  9. v0xyzzz

    v0xyzzz New Member

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    thanks! the barrier did solve the problem.. but I'm sorry, i'm a little bit confused.. What's the meaning of "something is connected backwards"?
    :D :D :D
     
  10. audioguru

    audioguru Well-Known Member Most Helpful Member

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    If a transistor is connected backwards then its collector and emitter are reversed. Instead of a current gain of 200, its gain will be about 5. It will work very poorly. American and European little transistors have their pin positions opposite. Then it is easy to use a different transistor and connect it backwards.
    I don't know what happens if a TSOP is connected backwards.
    I know the big BANG that happens if an electrolytic capacitor across a power supply is connected backwards.:D
     

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