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Stamp to monitor engine speed. — Parallax Forums

Stamp to monitor engine speed.

ArchiverArchiver Posts: 46,084
edited 2004-01-29 02:30 in General Discussion
I have a engine off a rider mower that i would like to monitor the engine speed.
For input, there is a big magnet on the flywheel that i could count 1
pass/revolution. How do i get the magnet passing to feed into pulsin? Or if
there is a better way to monitor each revolution of the engine??

Im a newbie in electronics so partnumbers or basic schematics (nirvana), I would
be eternally gratefull.



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Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-01-28 17:06
    At 07:35 AM 1/28/04 -0800, Mr. M wrote:
    >I have a engine off a rider mower that i would like to monitor the engine
    speed. For input, there is a big magnet on the flywheel that i could count 1
    pass/revolution. How do i get the magnet passing to feed into pulsin? Or if
    there is a better way to monitor each revolution of the engine??
    >
    >Im a newbie in electronics so partnumbers or basic schematics (nirvana), I
    would be eternally gratefull.

    Either a reed switch or a Hall Effect sensor will do what you want.
    Reed switches may also be known as proximity switches as they're used in burglar

    alarm intrusion detection.

    Regards,

    Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-28 17:08
    Just a suggestion: You might be able to use a hall-effect sensor to
    detect the magnet, then a one-shot to clean-up the pulse. Feed this
    into the Stamp and use the COUNT instruction to determine revolutions
    for a given period, then do a bit of math to determine speed.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: Mr. M [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=CI88ZXr0lrYgEcKNSyu1TTmKMEUxGeXFpT_kMMmQxlzXgjg2Dm6Ro-V-1cztBtkNaZ0JEdQIRWqCdltY9k7gXg]the_0utsider1@y...[/url
    Sent: Wednesday, January 28, 2004 9:36 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Stamp to monitor engine speed.


    I have a engine off a rider mower that i would like to monitor the
    engine speed. For input, there is a big magnet on the flywheel that i
    could count 1 pass/revolution. How do i get the magnet passing to feed
    into pulsin? Or if there is a better way to monitor each revolution of
    the engine??

    Im a newbie in electronics so partnumbers or basic schematics (nirvana),
    I would be eternally gratefull.
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-28 18:36
    The motor most likely has points and these are nothing more than a switch
    controlled by the motor rotation (every other revolution on 4 cycle engines,
    every cycle on two cycle engines). Use this switch coupled to an optical
    isolator and feed directly into the input pin on the stamp and you should
    have a simple way of detecting engine speed. For a four stroke engine, just
    multiply by two.

    jim
    http://www.geocities.com/jimforkin2003/


    Original Message
    From: Mr. M [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=jKqgrC7GS6a24Gyl_-hZ9uWbJLMNg8CuE9IOrv8RsvF1IfMc45PDfh5fwIKkhqWtxwTi2aYi4QrZtZMcfCs]the_0utsider1@y...[/url
    Sent: Wednesday, January 28, 2004 10:36 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Stamp to monitor engine speed.


    I have a engine off a rider mower that i would like to monitor the engine
    speed. For input, there is a big magnet on the flywheel that i could count 1
    pass/revolution. How do i get the magnet passing to feed into pulsin? Or if
    there is a better way to monitor each revolution of the engine??

    Im a newbie in electronics so partnumbers or basic schematics (nirvana), I
    would be eternally gratefull.



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  • ArchiverArchiver Posts: 46,084
    edited 2004-01-29 02:30
    You could put a few turns of wire around the spark plug wire and feed
    this to a Zener.

    It will save you the trouble of pulling the flywheel.

    Scope it to see how bad the spiking is and shunt the bad spiking with
    0.1 or 0.01 ceramic caps to clean up the signal. Don't be afraid to use
    more than one if necessary.

    There will be a pulse for every revolution on small engines with
    flywheel magnetos or crankshaft driven points.


    "Mr. M" wrote:
    >
    > I have a engine off a rider mower that i would like to monitor the engine
    speed. For input, there is a big magnet on the flywheel that i could count 1
    pass/revolution. How do i get the magnet passing to feed into pulsin? Or if
    there is a better way to monitor each revolution of the engine??
    >
    > Im a newbie in electronics so partnumbers or basic schematics (nirvana), I
    would be eternally gratefull.
    >
    >
    >
    > Do you Yahoo!?
    > Yahoo! SiteBuilder - Free web site building tool. Try it!
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.
    >
    >
    > Yahoo! Groups Links
    >
    > To visit your group on the web, go to:
    > http://groups.yahoo.com/group/basicstamps/
    >
    > To unsubscribe from this group, send an email to:
    > basicstamps-unsubscribe@yahoogroups.com
    >
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