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Question regarding this PIC16F628 tachometer schematic…

Discussion in 'Microcontrollers' started by mbu, Feb 12, 2007.

  1. mbu

    mbu New Member

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    Group,

    The stated accuracy (from his site) of Jose Pino tachometer is "between 200 to 9,999 RPM with a 0.3% of accuracy" which seems kind of poor to me. Is the poor accuracy due to the programming or is the accuracy limited to the hardware (timer, chip, etc.)?

    Thanks...
     
    Last edited: Mar 19, 2007
  2. mbu

    mbu New Member

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    Oops, double post!
     
  3. fever

    fever New Member

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    i thinks its because of the code.
    if your time interval (in which your counting the pulses) is too short it makes the tacho sensitive.in that site a guy(firoz) posted a video and pictures of the tacho to show how sensitive it is.
    and there is not ASM file of the code so that we can see or modify.has any one working on new code?
    and i am also having same issue as firoz.imean while starting LEDs are bright but when they start counting intensity get decreased.(have a look at the video http://www.youtube.com/watch?v=BJFa4jsq-LQ ) is this possible to control in code itself?
     
  4. dave

    Dave New Member

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  5. bananasiong

    bananasiong New Member

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    You can disassemble the hex file to become asm file, but very difficult to understand. Because the labels are not understandable anymore, just label1, label2, etc. Then you can modify the asm file again and compile again and load into the PIC again.
     
  6. mbu

    mbu New Member

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    Fever,

    Interesting video – thanks for posting it.

    I think the problem is that his programming is using a set amount of time and counting the input pulses at a rate of 1 pulse per revolution. That's why the low is 200 rpm. Your sensitivity issue could also a result of that. What rpm's have you tested yours with? My guess is that when you get it up to around 5,000 rpm's the 'sensitivity' issue will go away.
     
  7. fever

    fever New Member

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    well iam not good in this PIC coding stuff.
    so you might have observed while starting all 4 displays showing 8 then the last display counting from 9-0.i like it.is it possible to put some welcome message here.
    where i have to modify the code.i disassembled the hex using winpicpro and got this
     

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    Last edited: Mar 20, 2007
  8. mbu

    mbu New Member

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    Gee Whiz! :eek: That disassembled code has over 750 lines of instruction. Is that because the code was written in something other than assembly and when it was compiled it is not optimized?
     
    Last edited: Mar 20, 2007
  9. fever

    fever New Member

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    no idea.
    but i find it very difficult to modify it.
     
  10. mbu

    mbu New Member

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  11. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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    Originally Posted by Nigel Goodwin
    :)

    Sorry Nigel, I could not resist.
     
  12. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Use a later version of WinPicProg, it adds GPR names which helps to make it a bit clearer. Like this:
     

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  13. fever

    fever New Member

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    thanks
    but i don't understand how he did that display at startup - 9-0 counting(in tach-1) and the name display in tach-2.
    there is some more stuff in address-Eeprom Data tab(ICprog).is this causing to display those startups?
     
  14. fever

    fever New Member

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    well with some more search on internet i found a german site where ppl were discussing abt AVR based tacho(7-segemnt).
    have a look at the below zip file.
    and if any one interested in making it,pls do post ur experience.

    and i don't understand some points in this design
    1.what is the purpose of red,yellow LEDs and transistors
    2.where and what to modify (in code) to maker it work for single cylinder engine.
     

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    Last edited: Mar 23, 2007

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