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Robot distance measurements — Parallax Forums

Robot distance measurements

ArchiverArchiver Posts: 46,084
edited 2002-09-29 21:07 in General Discussion
I was wondering can anybody think of a way to determine the distance a
wheeled robot (such as the BOE-BOT) using a standard PS/2 ball mouse
that touches the floor? I was thinking if I used the PAK PS/2 keyboard
decoder that I might be able to come up with a system. I would be using
a standard BS2 and a BOE. Any thoughts, comments, suggestions, or code
(hint hint) would be greatly appreciated. I have been using stamps for
about 4 years now so don't be afraid to throw something big at me.
Thanks in advance,
Jacob Dilles (KG4AUW)


[noparse][[/noparse]Non-text portions of this message have been removed]

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-09-28 17:47
    Which ripple counter part numbers are you using
    Are they up-down or straight counts

    Original Message
    From: cholm@m... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=L5nFbSaEzrmWS4AqPvZ1VpdOnQP9eCJ19wO-VJgYj1hEkuO9wsp6lytjV_ROpsXsSWcbVK-FyZM]cholm@m...[/url
    Sent: Saturday, September 28, 2002 12:58 PM
    To: basicstamps@yahoogroups.com
    Subject: RE: [noparse][[/noparse]basicstamps] Robot distance measurements

    For a similar problem, of handling the needs of two simultaneous measurement
    or calculation steps, I decided to have my wheel revolution counter feed a
    hardware ripple counter so I didn't have to worry about missing counts, then
    read the ripple counter when I have time in the program. That allowed me
    to worry less about program timing.

    Ripple counters are pretty easy to use, don't require much more hardware to
    integrate with a stamp, and are cheap. However, they will take a couple
    more of your serial ports to integrate than a simple wheel revolution
    counter.

    Original Message
    From: David Lawrence [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=YB44VpGg75NLK-oYParzQT-sWzlgIxM0eehH9ouwwLrTFe2aTWo8TLAIPcJv_nCDJVvXUSUoKRJLY5a2]david@r...[/url
    Sent: Saturday, September 28, 2002 1:44 PM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Robot distance measurements



    Original Message
    From: "J. Dilles" <theshadow2754@h...>
    To: "Basic Stamps @ Yahoo" <basicstamps@yahoogroups.com>
    Sent: Friday, September 27, 2002 12:07 PM
    Subject: [noparse][[/noparse]basicstamps] Robot distance measurements


    > I was wondering can anybody think of a way to determine the distance a
    > wheeled robot (such as the BOE-BOT) using a standard PS/2 ball mouse
    > that touches the floor? I was thinking if I used the PAK PS/2 keyboard
    > decoder that I might be able to come up with a system. I would be using
    > a standard BS2 and a BOE. Any thoughts, comments, suggestions, or code
    > (hint hint) would be greatly appreciated. I have been using stamps for
    > about 4 years now so don't be afraid to throw something big at me.
    > Thanks in advance,
    > Jacob Dilles (KG4AUW)

    Hi Jacob:

    Adhesive labels printed with radial segments using a QRD1114 Fairchild
    sensor works very well - cheap and simple. 36 segments gave better than 1/4"
    resolution, but 22 segs is good starting point.

    With only one channel it is not possible to sense direction but you already
    have that info by way of driving the Servo, therefore you know whether to
    Incr/Decr the distance count.

    That secondary task of Servos 'in parallel' leads to a much bigger problem
    than the actual distance sensing. How can you sit in a tight loop timing the
    Servo AND carefully monitor the Encoder? A single code loop for both, timing
    2 servos + monitoring 2 encoders + calculating dynamic padding is possible,
    but that is not good practice, and is a dead end.

    If you go to
    www.rhombus-tek.com/SMt_Rob.pdf
    you will see how a BS2 can handle 2 Servos + 2 Wheel Encoders + DevanTech +
    Sharp + Receive PC data at 28,800 baud. All in parallel.


    David H Lawrence

    Simple Multi-tasking, Co-Processors, Compilers, and microGUI
    mailto:david@r...
    http://www.rhombus-tek.com



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  • ArchiverArchiver Posts: 46,084
    edited 2002-09-28 17:58
    For a similar problem, of handling the needs of two simultaneous measurement
    or calculation steps, I decided to have my wheel revolution counter feed a
    hardware ripple counter so I didn't have to worry about missing counts, then
    read the ripple counter when I have time in the program. That allowed me
    to worry less about program timing.

    Ripple counters are pretty easy to use, don't require much more hardware to
    integrate with a stamp, and are cheap. However, they will take a couple
    more of your serial ports to integrate than a simple wheel revolution
    counter.

    Original Message
    From: David Lawrence [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=lLuOdfLVUcbEvGoJ54iu8WmEvDVJKMTyWPpAAnujMm-QP_bmvj_ecCwbux2MlsGF5b29AOv9wdoCFPA]david@r...[/url
    Sent: Saturday, September 28, 2002 1:44 PM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Robot distance measurements



    Original Message
    From: "J. Dilles" <theshadow2754@h...>
    To: "Basic Stamps @ Yahoo" <basicstamps@yahoogroups.com>
    Sent: Friday, September 27, 2002 12:07 PM
    Subject: [noparse][[/noparse]basicstamps] Robot distance measurements


    > I was wondering can anybody think of a way to determine the distance a
    > wheeled robot (such as the BOE-BOT) using a standard PS/2 ball mouse
    > that touches the floor? I was thinking if I used the PAK PS/2 keyboard
    > decoder that I might be able to come up with a system. I would be using
    > a standard BS2 and a BOE. Any thoughts, comments, suggestions, or code
    > (hint hint) would be greatly appreciated. I have been using stamps for
    > about 4 years now so don't be afraid to throw something big at me.
    > Thanks in advance,
    > Jacob Dilles (KG4AUW)

    Hi Jacob:

    Adhesive labels printed with radial segments using a QRD1114 Fairchild
    sensor works very well - cheap and simple. 36 segments gave better than 1/4"
    resolution, but 22 segs is good starting point.

    With only one channel it is not possible to sense direction but you already
    have that info by way of driving the Servo, therefore you know whether to
    Incr/Decr the distance count.

    That secondary task of Servos 'in parallel' leads to a much bigger problem
    than the actual distance sensing. How can you sit in a tight loop timing the
    Servo AND carefully monitor the Encoder? A single code loop for both, timing
    2 servos + monitoring 2 encoders + calculating dynamic padding is possible,
    but that is not good practice, and is a dead end.

    If you go to
    www.rhombus-tek.com/SMt_Rob.pdf
    you will see how a BS2 can handle 2 Servos + 2 Wheel Encoders + DevanTech +
    Sharp + Receive PC data at 28,800 baud. All in parallel.


    David H Lawrence

    Simple Multi-tasking, Co-Processors, Compilers, and microGUI
    mailto:david@r...
    http://www.rhombus-tek.com



    ---
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    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2002-09-28 18:14
    This is the part number that I used:

    http://www.mil.ufl.edu/links/datasheets/Counters/mc74hc393.pdf


    Original Message
    From: Sadler Porter [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=KZHH_d6w1aidoJTkG5Z1PN7k5og81GnNt_uPmZgPpQy_Iemk9haXqS_ErN0kqMXz3xIMGHyagvskqeurS9du]porter.sadler@s...[/url
    Sent: Saturday, September 28, 2002 12:47 PM
    To: basicstamps@yahoogroups.com
    Subject: RE: [noparse][[/noparse]basicstamps] Robot distance measurements


    Which ripple counter part numbers are you using
    Are they up-down or straight counts

    Original Message
    From: cholm@m... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=O9NiBzHepJT_HqHqhV9sCU7i5j-T0mrBahvO85wbai5chq6Fd9VnUuxO1uUpY_-a0RHZpdrszA]cholm@m...[/url
    Sent: Saturday, September 28, 2002 12:58 PM
    To: basicstamps@yahoogroups.com
    Subject: RE: [noparse][[/noparse]basicstamps] Robot distance measurements

    For a similar problem, of handling the needs of two simultaneous measurement
    or calculation steps, I decided to have my wheel revolution counter feed a
    hardware ripple counter so I didn't have to worry about missing counts, then
    read the ripple counter when I have time in the program. That allowed me
    to worry less about program timing.

    Ripple counters are pretty easy to use, don't require much more hardware to
    integrate with a stamp, and are cheap. However, they will take a couple
    more of your serial ports to integrate than a simple wheel revolution
    counter.

    Original Message
    From: David Lawrence [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=_HDFCFIyJQHbYW8YbTiAjxVoa3H7vrN68mDx3tntF-68dFycgwnHOgFAIo5A0kxG8VEieIdJzNH2_hTiEpKg]david@r...[/url
    Sent: Saturday, September 28, 2002 1:44 PM
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Robot distance measurements



    Original Message
    From: "J. Dilles" <theshadow2754@h...>
    To: "Basic Stamps @ Yahoo" <basicstamps@yahoogroups.com>
    Sent: Friday, September 27, 2002 12:07 PM
    Subject: [noparse][[/noparse]basicstamps] Robot distance measurements


    > I was wondering can anybody think of a way to determine the distance a
    > wheeled robot (such as the BOE-BOT) using a standard PS/2 ball mouse
    > that touches the floor? I was thinking if I used the PAK PS/2 keyboard
    > decoder that I might be able to come up with a system. I would be using
    > a standard BS2 and a BOE. Any thoughts, comments, suggestions, or code
    > (hint hint) would be greatly appreciated. I have been using stamps for
    > about 4 years now so don't be afraid to throw something big at me.
    > Thanks in advance,
    > Jacob Dilles (KG4AUW)

    Hi Jacob:

    Adhesive labels printed with radial segments using a QRD1114 Fairchild
    sensor works very well - cheap and simple. 36 segments gave better than 1/4"
    resolution, but 22 segs is good starting point.

    With only one channel it is not possible to sense direction but you already
    have that info by way of driving the Servo, therefore you know whether to
    Incr/Decr the distance count.

    That secondary task of Servos 'in parallel' leads to a much bigger problem
    than the actual distance sensing. How can you sit in a tight loop timing the
    Servo AND carefully monitor the Encoder? A single code loop for both, timing
    2 servos + monitoring 2 encoders + calculating dynamic padding is possible,
    but that is not good practice, and is a dead end.

    If you go to
    www.rhombus-tek.com/SMt_Rob.pdf
    you will see how a BS2 can handle 2 Servos + 2 Wheel Encoders + DevanTech +
    Sharp + Receive PC data at 28,800 baud. All in parallel.


    David H Lawrence

    Simple Multi-tasking, Co-Processors, Compilers, and microGUI
    mailto:david@r...
    http://www.rhombus-tek.com



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    recipient(s), you are hereby notified that any dissemination,
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    the sender and delete this e-mail message from your computer.




    [noparse][[/noparse]Non-text portions of this message have been removed]


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  • ArchiverArchiver Posts: 46,084
    edited 2002-09-28 18:43

    Original Message
    From: "J. Dilles" <theshadow2754@h...>
    To: "Basic Stamps @ Yahoo" <basicstamps@yahoogroups.com>
    Sent: Friday, September 27, 2002 12:07 PM
    Subject: [noparse][[/noparse]basicstamps] Robot distance measurements


    > I was wondering can anybody think of a way to determine the distance a
    > wheeled robot (such as the BOE-BOT) using a standard PS/2 ball mouse
    > that touches the floor? I was thinking if I used the PAK PS/2 keyboard
    > decoder that I might be able to come up with a system. I would be using
    > a standard BS2 and a BOE. Any thoughts, comments, suggestions, or code
    > (hint hint) would be greatly appreciated. I have been using stamps for
    > about 4 years now so don't be afraid to throw something big at me.
    > Thanks in advance,
    > Jacob Dilles (KG4AUW)

    Hi Jacob:

    Adhesive labels printed with radial segments using a QRD1114 Fairchild
    sensor works very well - cheap and simple. 36 segments gave better than 1/4"
    resolution, but 22 segs is good starting point.

    With only one channel it is not possible to sense direction but you already
    have that info by way of driving the Servo, therefore you know whether to
    Incr/Decr the distance count.

    That secondary task of Servos 'in parallel' leads to a much bigger problem
    than the actual distance sensing. How can you sit in a tight loop timing the
    Servo AND carefully monitor the Encoder? A single code loop for both, timing
    2 servos + monitoring 2 encoders + calculating dynamic padding is possible,
    but that is not good practice, and is a dead end.

    If you go to
    www.rhombus-tek.com/SMt_Rob.pdf
    you will see how a BS2 can handle 2 Servos + 2 Wheel Encoders + DevanTech +
    Sharp + Receive PC data at 28,800 baud. All in parallel.


    David H Lawrence

    Simple Multi-tasking, Co-Processors, Compilers, and microGUI
    mailto:david@r...
    http://www.rhombus-tek.com



    ---
    Outgoing mail is certified Virus Free.
    Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.384 / Virus Database: 216 - Release Date: 8/21/02
  • ArchiverArchiver Posts: 46,084
    edited 2002-09-29 21:07
    Thank you all for you responses. but I was thinking more along the lines
    of a actual computer mouse attached to the bottom of the 'bot. I think
    a mouse would work better then the 2 wheel encoders pulled out of one
    because it is pre-made for tracking movement.

    If anyone knows anything about how computer mice work, all help would be
    appreciated. a few questions I have right now are:

    is the output of the mouse is absolute or relative?
    If it is absolute, does it reset every once in a while or just keep
    going?
    how is the data sent on the bus?
    Is it feasible to have a bs2 read this data, or should a separate
    decoder be used (pac or pic)?

    And finally, am I missing something that could set me up for total
    failure??? Anyway, thank you all again, Jacob


    [noparse][[/noparse]Non-text portions of this message have been removed]
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