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Thread: 555 ir sensor problem.. plz help me

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  1. #1

    Default 555 ir sensor problem.. plz help me

    Am doing a line tracer robot... I ve been trying to make an 38khz IR sensor using 555 in astable mode.... Its not working out... I dont know de reason..I am not able to go beyond this in my project.. Can I use 2051 or 8051 directly to generate this 38Khz square wave form.. Will it work out.. if so plz give de circuit diagram

  2. #2
    Administrator T-1000 rao's Avatar
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    one word reply for this post...

    GOOGLE


    Rao

  3. #3

    Default it works fine

    I just completed mine ... I at first used uC(PIC) to generate the 38khz .. but I failed I don't know why ...but the 555 timer works...
    http://robotroom.com/Infrared555.html

    the circuit in thsi link works for me fine .... but R1(15 K) given was not generating 38khz.. I reduced to 5k along with a 5k pot (in series) as given ... and it worked for me ...it gave me a clearance of 8-9cm though not good but still enough...

    1> look at the IR diode connection ...see the diode sign ....
    2> use that 1nF capacitor surely...
    3> Is the IR working .. trace it with a mobile camera or a digi cam ...I use a infrared detector used by the TV mechanic to test the remote control (Rs 50 at kolkata)
    4> select the resistance in series with the IR carefully .... I used 330 ... I will try other smaller one to see if the range increases..
    [/url]

  4. #4

    Default me again

    I reduced the resistance in series with the IR to 100 from 330 ohm and now I am getting range of 27cm for pure white object and 12cm for a dark object(back side of a floppy) ... its cool man !

  5. #5

    Default

    Thanks for ur help.. But now my tsop seems to be detecting IR only a fraction of seconds when IR falls on it.... The LED connected to tsop blinks only once when IR falls on tsop..Every time I keep my hand in between IR LED and tsop and release it, the LED blinks..but when i use my tv remote its able to detect continuously... hope u understand my problem..

  6. #6
    Super Moderator T-1000 docel's Avatar
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    Quote Originally Posted by Dissac
    Thanks for ur help.. But now my tsop seems to be detecting IR only a fraction of seconds when IR falls on it.... The LED connected to tsop blinks only once when IR falls on tsop.......
    :twisted: WHENEVER you make a Circuit, make it a point to READ the Manufacturers DATASHEET :evil:

    There is also a SEARCH option for ALL answers to STUPID questions!

    Moreover, you arent doing anything new but something that has been done by a BILLION people.

    The SENSORS Forum has plenty of answers to the above stupidity!!!
    docel
    ^Anything is possible..
    after YOU prove it!!

    http://bangalorerobotics.tripod.com

  7. #7

    Default

    Quote Originally Posted by Dissac
    Thanks for ur help.. But now my tsop seems to be detecting IR only a fraction of seconds when IR falls on it.... The LED connected to tsop blinks only once when IR falls on tsop..Every time I keep my hand in between IR LED and tsop and release it, the LED blinks..but when i use my tv remote its able to detect continuously... hope u understand my problem..
    "docel" seems to be quiet angry with you and he must be....

    nway .. have u measured the frequency that u have generated using 555.. ?
    I think u haven't ....

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    Senior Member Cyborg
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    http://www.onlinetps.com/
    Online Component Shoppe
    Microcontrollers and Solar Robotics Stuffs at cheap rates

  9. #9
    Super Moderator T-1000 docel's Avatar
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    Default Datasheet Datasheet Datasheet Datasheet

    [quote="TirthankarMukherjeePIC"]
    Quote Originally Posted by Dissac

    "docel" seems to be quiet angry with you and he must be....

    nway ..
    I repeat, once again: HAVE YOU READ the TSOP Datasheet :?:
    docel
    ^Anything is possible..
    after YOU prove it!!

    http://bangalorerobotics.tripod.com

  10. #10

    Default

    what 'docel' would like you to see is the pulse train length (burst length) should be around 10-70 pulses of 38khz beam after which there should be a break of so much time....

    You can do it with any microcontroller with a timer and a timer interrupt easily or otherwise with a bit of coding.

    if you are using 555 then try using another timer with duty cycle abt 2 times the 38kHz beam and then give its output to the pin 4(reset )of your 38kHz generator....

    The output from the TSOP would be be a waveform similar to the second timer ouput(inverted since TSOP active low output)...

    Anyway the fact needs to be stressed that you should read the Datasheet of any component befor you use it.It generally has everyting you need to know to use it in the best way...

    regards

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