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range detection system — Parallax Forums

range detection system

ArchiverArchiver Posts: 46,084
edited 2003-04-25 23:54 in General Discussion
Hi folks,

first of all, let me say thanks to all of the responses regarding the a/c
coil transient problem. got lots of good advice and was finally able to put
that sucker to bed.

now, I've got another problem. I need a way to reliably detect the presence
of and measure distances to varying types of targets (children, bikes, etc)
from a fixed location. I don't need to worry about trying to identify the
targets, I only need to know that something is there and about how far away.
it would also be nice to have an idea of direction of motion, and the
ability to adjust the beam pattern (both the spread and the general
direction; this does NOT need to be done on the fly, only once to set up the
system).

I was thinking ultrasonics would be one way (I found something from
acroname.com that goes for about 30 bucks and some change- if anyone has any
experience with that product or can suggest something better, please do so).
I also thought maybe a PIR device, though I can't see it being used for
range finding, and it seems like it would be susceptable to interference in
daylight), or possibly RADAR, though I'm not familiar with such devices on
the experimenter market for cheap -- the last point is important. I don't
want to spend more than $30 or $40 for this thing.

thanks again for any and all ideas, and I'll be looking forward to hearing
from people.


d...

**************************************************************************
* David Okagaki dokagaki@w...
*
* "The light at the end of the tunnel is that of the on coming train!"
*
**************************************************************************

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-04-23 01:25
    Sent: Tuesday, April 22, 2003 5:59 PM
    Subject: [noparse][[/noparse]basicstamps] range detection system

    Hi Dave,

    If sunlight is going to be a factor, look into the Devantech SRF04 ultrasonic
    rangefinder. It's within your target price range, and Parallax has demo code
    for using them. IR is great, but not much use outdoors or in strong sunlight.

    < http://www.parallax.com/Downloads/Documentation/Devantech_SRF04.pdf >

    Regards,

    -Bruce
    tech@r...
    http://www.rentron.com
  • ArchiverArchiver Posts: 46,084
    edited 2003-04-23 02:24
    Dave,
    The Devantech SRFO4 ultrasonic device is a great way to do what your
    doing, if you need to adjust the beam pattern, I don't think you can
    effectively but you can mount it on a servo head.

    -Mike

    Original Message
    From: Dave [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=fcBSRSFwrFRxG4LIJ5nkvckpnBJGrKyh9Qr9sqUSFtyTX4xyJzDPR9VTpcew6nWCDR_xUMpU8hg7eIX0gPG0CrVFC0Y]dokagaki@w...[/url
    Sent: Tuesday, April 22, 2003 7:59 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] range detection system

    Hi folks,

    first of all, let me say thanks to all of the responses regarding the
    a/c
    coil transient problem. got lots of good advice and was finally able to
    put
    that sucker to bed.

    now, I've got another problem. I need a way to reliably detect the
    presence
    of and measure distances to varying types of targets (children, bikes,
    etc)
    from a fixed location. I don't need to worry about trying to identify
    the
    targets, I only need to know that something is there and about how far
    away.
    it would also be nice to have an idea of direction of motion, and the
    ability to adjust the beam pattern (both the spread and the general
    direction; this does NOT need to be done on the fly, only once to set up
    the
    system).

    I was thinking ultrasonics would be one way (I found something from
    acroname.com that goes for about 30 bucks and some change- if anyone has
    any
    experience with that product or can suggest something better, please do
    so).
    I also thought maybe a PIR device, though I can't see it being used for
    range finding, and it seems like it would be susceptable to interference
    in
    daylight), or possibly RADAR, though I'm not familiar with such devices
    on
    the experimenter market for cheap -- the last point is important. I
    don't
    want to spend more than $30 or $40 for this thing.

    thanks again for any and all ideas, and I'll be looking forward to
    hearing
    from people.


    d...

    ************************************************************************
    **
    * David Okagaki dokagaki@w...
    *
    * "The light at the end of the tunnel is that of the on coming train!"
    *
    ************************************************************************
    **


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  • ArchiverArchiver Posts: 46,084
    edited 2003-04-25 23:45
    Hello,

    I have a suggestion. Take a look at Ramsey Electronics
    (ramseyelectronics.com) kit number MD3. It is a
    microwave motion detection kit that works by detecting
    a dopler shift in a microwave signal. It's $29.95 and
    includes decent documentation that should be able to
    be used to detect objects regardless of ambient
    conditions and has a distance of 12'. The description
    also mentions direction capabilities. Let us know if
    this works as it could be valuable for robotics
    proximity detection as well.

    DrDiode

    --- Dave <dokagaki@w...> wrote:
    > Hi folks,
    >
    > first of all, let me say thanks to all of the
    > responses regarding the a/c
    > coil transient problem. got lots of good advice and
    > was finally able to put
    > that sucker to bed.
    >
    > now, I've got another problem. I need a way to
    > reliably detect the presence
    > of and measure distances to varying types of targets
    > (children, bikes, etc)
    > from a fixed location. I don't need to worry about
    > trying to identify the
    > targets, I only need to know that something is there
    > and about how far away.
    > it would also be nice to have an idea of direction
    > of motion, and the
    > ability to adjust the beam pattern (both the spread
    > and the general
    > direction; this does NOT need to be done on the fly,
    > only once to set up the
    > system).
    >
    > I was thinking ultrasonics would be one way (I found
    > something from
    > acroname.com that goes for about 30 bucks and some
    > change- if anyone has any
    > experience with that product or can suggest
    > something better, please do so).
    > I also thought maybe a PIR device, though I can't
    > see it being used for
    > range finding, and it seems like it would be
    > susceptable to interference in
    > daylight), or possibly RADAR, though I'm not
    > familiar with such devices on
    > the experimenter market for cheap -- the last point
    > is important. I don't
    > want to spend more than $30 or $40 for this thing.
    >
    > thanks again for any and all ideas, and I'll be
    > looking forward to hearing
    > from people.
    >
    >
    > d...
    >
    >
    **************************************************************************
    > * David Okagaki
    > dokagaki@w...
    > *
    > * "The light at the end of the tunnel is that of the
    > on coming train!"
    > *
    >
    **************************************************************************
    >
    >
    > 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.
    >
    >
    > Your use of Yahoo! Groups is subject to
    > http://docs.yahoo.com/info/terms/
    >
    >


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  • ArchiverArchiver Posts: 46,084
    edited 2003-04-25 23:54
    Got one, and it does work. The board is a bit big for a small robot, but on
    a bigger robot it would be a good for detecting a perimeter incursion. Mine
    will probably wind up on the back porch to warn me of visitors and probably
    scare the cats away from the trash.


    Original Message

    > I have a suggestion. Take a look at Ramsey Electronics
    > (ramseyelectronics.com) kit number MD3. It is a
    > microwave motion detection kit that works by detecting
    > a dopler shift in a microwave signal. It's $29.95 and
    > includes decent documentation that should be able to
    > be used to detect objects regardless of ambient
    > conditions and has a distance of 12'. The description
    > also mentions direction capabilities. Let us know if
    > this works as it could be valuable for robotics
    > proximity detection as well.

    > > first of all, let me say thanks to all of the
    > > responses regarding the a/c
    > > coil transient problem. got lots of good advice and
    > > was finally able to put
    > > that sucker to bed.
    > >
    > > now, I've got another problem. I need a way to
    > > reliably detect the presence
    > > of and measure distances to varying types of targets
    > > (children, bikes, etc)
    > > from a fixed location. I don't need to worry about
    > > trying to identify the
    > > targets, I only need to know that something is there
    > > and about how far away.
    > > it would also be nice to have an idea of direction
    > > of motion, and the
    > > ability to adjust the beam pattern (both the spread
    > > and the general
    > > direction; this does NOT need to be done on the fly,
    > > only once to set up the
    > > system).
    > >
    > > I was thinking ultrasonics would be one way (I found
    > > something from
    > > acroname.com that goes for about 30 bucks and some
    > > change- if anyone has any
    > > experience with that product or can suggest
    > > something better, please do so).
    > > I also thought maybe a PIR device, though I can't
    > > see it being used for
    > > range finding, and it seems like it would be
    > > susceptable to interference in
    > > daylight), or possibly RADAR, though I'm not
    > > familiar with such devices on
    > > the experimenter market for cheap -- the last point
    > > is important. I don't
    > > want to spend more than $30 or $40 for this thing.
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