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Best Sensor Choice? — Parallax Forums

Best Sensor Choice?

ArchiverArchiver Posts: 46,084
edited 2004-02-11 06:13 in General Discussion
Hi All,

I'm new to BASIC stamps, and have a sensor question.

I'm building an application that has a small revolving paddle, driven
by a Parallax Servo. When the Stamp recieves a signal, the servo will
be activated. I'd like to install a sensor that detects when the
paddle passes it, and stop the servo. The paddle is thin, ~ 1/16th of
an inch. It's currently semi-frosted plastic, but I can easily paint
a line on it.

I was thinking about using a QTI Sensor
(http://www.parallax.com/detail.asp?product_id=555-27401) but I'm not
sure if it will be able to detect the very thin line passing it.

I could try using a stepper motor, but I like the idea of working with
a sensor, as this project is more fun hobby then serious application.

Thanks,
Chris McAvoy

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-02-11 00:58
    --- In basicstamps@yahoogroups.com, "Chris McAvoy" <mcavoy76@h...>
    wrote:
    > Hi All,
    >
    > I'm new to BASIC stamps, and have a sensor question.
    >
    > I'm building an application that has a small revolving paddle,
    driven
    > by a Parallax Servo. When the Stamp recieves a signal, the servo
    will
    > be activated. I'd like to install a sensor that detects when the
    > paddle passes it, and stop the servo. The paddle is thin, ~ 1/16th
    of
    > an inch. It's currently semi-frosted plastic, but I can easily
    paint
    > a line on it.

    The reflectivity is the key. the 1/16 might work, and you may be
    able to add a little shoulder to increase the area?

    Another method is a hall effect sensor, but then you would need a
    small magnet on the paddle.

    Another idea is to put the sensor on the shaft of the servo.

    Dave
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-11 06:13
    Chris,

    If the paddle can pass through a slotted phototransistor switch (see
    Optek switch, Digikey 365-1008-ND), I would use it. Otherwise, glue a
    small magnet on the paddle, and use a Hall sensor.

    Dennis
    Original Message
    From: Chris McAvoy [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=QufhYpb4OckiEvxMdx00kveuGSp_ccW1QjGUyTQI8mkVT23cLsYty2FEB5wNMsT5_KDlNkK8vDnIPcQ]mcavoy76@h...[/url
    Sent: Tuesday, February 10, 2004 12:14 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Best Sensor Choice?


    Hi All,

    I'm new to BASIC stamps, and have a sensor question.

    I'm building an application that has a small revolving paddle, driven by
    a Parallax Servo. When the Stamp recieves a signal, the servo will be
    activated. I'd like to install a sensor that detects when the paddle
    passes it, and stop the servo. The paddle is thin, ~ 1/16th of an inch.
    It's currently semi-frosted plastic, but I can easily paint a line on
    it.

    I was thinking about using a QTI Sensor
    (http://www.parallax.com/detail.asp?product_id=555-27401) but I'm not
    sure if it will be able to detect the very thin line passing it.

    I could try using a stepper motor, but I like the idea of working with a
    sensor, as this project is more fun hobby then serious application.

    Thanks,
    Chris McAvoy






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