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Rotational encoder help please! — Parallax Forums

Rotational encoder help please!

ArchiverArchiver Posts: 46,084
edited 2003-06-24 16:02 in General Discussion
Hi,

I needed some help with a rotational encoder I'm trying to make. The
idea here is to have a vertical PVC pipe and some sort of system to
count the revolutions. I was thinking along the lines of maybe
cutting a small hole in the pipe, and putting an IR LED inside the
pipe and the receiver outside the pipe so that every time the pipe
turns one time the hole lets the IR light shine through. Do you think
this would work? Is there something better then this?

Thanks in advance!

E

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-06-23 20:05
    In a message dated 6/23/2003 8:55:53 AM Pacific Daylight Time,
    Air_force@w... writes:

    > Hi,
    >
    > I needed some help with a rotational encoder I'm trying to make. The
    > idea here is to have a vertical PVC pipe and some sort of system to
    > count the revolutions. I was thinking along the lines of maybe
    > cutting a small hole in the pipe, and putting an IR LED inside the
    > pipe and the receiver outside the pipe so that every time the pipe
    > turns one time the hole lets the IR light shine through. Do you think
    > this would work? Is there something better then this?
    >
    > Thanks in advance!
    >
    > E
    >

    Your idea will work.

    For a LITTLE more simplicity you may want to consider a magnet mounted on the
    pipe and a magnetic pick up sensor on to sense the rotation.......Less
    wiring....


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-06-23 20:27
    In a message dated 6/23/2003 8:55:53 AM Pacific Daylight Time,
    Air_force@w... writes:

    > Hi,
    >
    > I needed some help with a rotational encoder I'm trying to make. The
    > idea here is to have a vertical PVC pipe and some sort of system to
    > count the revolutions. I was thinking along the lines of maybe
    > cutting a small hole in the pipe, and putting an IR LED inside the
    > pipe and the receiver outside the pipe so that every time the pipe
    > turns one time the hole lets the IR light shine through. Do you think
    > this would work? Is there something better then this?
    >
    > Thanks in advance!
    >
    > E
    >

    One other thought I forgot to mention. If your the IR sensors do not work
    well when exposed to ambient sunlight


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-06-24 03:24
    Thanks for your quick response! I will try using the magnet idea! I did have
    one more question: How do you count the number of events and how to
    determine the rate of events (events/time)? In this case, the rate of events
    would be RPM.


    Original Message
    From: <smartdim@a...>
    To: <basicstamps@yahoogroups.com>
    Sent: Monday, June 23, 2003 3:05 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Rotational encoder help please!


    > In a message dated 6/23/2003 8:55:53 AM Pacific Daylight Time,
    > Air_force@w... writes:
    >
    > > Hi,
    > >
    > > I needed some help with a rotational encoder I'm trying to make. The
    > > idea here is to have a vertical PVC pipe and some sort of system to
    > > count the revolutions. I was thinking along the lines of maybe
    > > cutting a small hole in the pipe, and putting an IR LED inside the
    > > pipe and the receiver outside the pipe so that every time the pipe
    > > turns one time the hole lets the IR light shine through. Do you think
    > > this would work? Is there something better then this?
    > >
    > > Thanks in advance!
    > >
    > > E
    > >
    >
    > Your idea will work.
    >
    > For a LITTLE more simplicity you may want to consider a magnet mounted on
    the
    > pipe and a magnetic pick up sensor on to sense the rotation.......Less
    > wiring....
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    > To UNSUBSCRIBE, just send mail to:
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    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-06-24 04:08
    In a message dated 6/23/2003 7:29:29 PM Pacific Daylight Time,
    Air_force@w... writes:

    > Thanks for your quick response! I will try using the magnet idea! I did
    > have
    > one more question: How do you count the number of events and how to
    > determine the rate of events (events/time)? In this case, the rate of events
    > would be RPM.
    >

    To answer your question, need some basic facts such as:

    Is the rotating device ever stopped? Also, what is the approximate maximum
    rotation speed?

    There are a couple of commands the stamp has that will easily count the
    pulses, but depending upon answers to the questions above will determine which
    command to use, and possibly some "interface" hardware between the output of the

    magnetic sensor and the stamp...

    In summary though, it will not be difficult, the stamp can easily be
    configured to measure the rotation speed of your rotating device.

    What is the minimum and maximum revs/min? How accurate does it need to be?



    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-06-24 16:02
    Is the rotating device ever stopped? Not that should be measured.
    This is a testing device to measure the effects of water over pipes
    of different diameter at different speeds.

    Also, what is the approximate maximum rotation speed? less than 100
    RPM And the min would be about 20 RPM.
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