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Line Sensor Location on Scribbler — Parallax Forums

Line Sensor Location on Scribbler

rkgordon3rkgordon3 Posts: 1
edited 2012-05-21 14:58 in Robotics
Are there any official numbers on exact position of lines sensors on Scribbler with respect to, say, center of robot?

Thanks
Rob

Comments

  • ercoerco Posts: 20,256
    edited 2012-05-18 10:26
    You mean the distance between the two sensors? I can check later if no one beats me to it.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-18 11:14
    I get 7.70mm between the two sensors.

    It's always nice to give erco a good beating.
  • ercoerco Posts: 20,256
    edited 2012-05-18 11:18
    Confound you again, Duane. Do you never rest?

    But you didn't specify, is that the center to center distance, or inside edge to inside edge, the gap between sensors?

    And if it's actually 7.69 or 7.71 mm, you'll never hear the end of it.
  • hover1hover1 Posts: 1,929
    edited 2012-05-18 11:20
    This is not official. You would need a CAD file. But....

    You have approx. 5/16 between sensors. The center can not really be defined as the is about an 1/8" slop side-to-side on the back wheel.

    Jim

    EDIT: DARN!! Two posts before I finished. Duane must have had one by his side. I had to go up two flights of stairs. :)
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-18 11:23
    erco wrote: »
    Confound you again, Duane. Do you never rest?

    But you didn't specify, is that the center to center distance, or inside edge to inside edge, the gap between sensors?

    And if it's actually 7.69 or 7.71 mm, you'll never hear the end of it.

    Center to center or outside edge to inside edge or inside edge to outside edge.

    To be honest, that's probably +/- 0.04mm.
  • hover1hover1 Posts: 1,929
    edited 2012-05-18 11:25
    Duane Degn wrote: »
    Center to center or outside edge to inside edge or inside edge to outside edge.

    To be honest, that's probably +/- 0.04mm.

    Would a piece of tape really mind? :)

    Jim
  • ercoerco Posts: 20,256
    edited 2012-05-18 11:54
    Duane Degn wrote: »
    To be honest, that's probably +/- 0.04mm.

    Pretty loosey-goosey for all your normal precisitudinosity, Mr Degn! It's almost as though you were rushing to post before I did!
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-18 19:39
    Oh for heavens' sake! Who said the distance even exists in metric units? It's 0.315 by golly INCHES! center-to-center. (For all you metric weenies, that translates to 8mm.)

    -Phil
  • WhitWhit Posts: 4,191
    edited 2012-05-18 19:59
    Get em Phil!
  • ercoerco Posts: 20,256
    edited 2012-05-19 07:31
    Whit, just who's side are you on? I thought you were my Dawg!
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-19 10:41
    Phil's foot must have gotten shorter from the break. Now he want the world to conform to a new standard of length (his foot).

    Sorry old man, it doesn't work that way.

    If there really is 8mm between those sensors, I'll send you two Propeller chips (I think only cog #0 is bad on them, the other seven should work).
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-19 11:04
    Okay, I was a little off. It's 0.317", or 8.05mm. Here's the proof:

    attachment.php?attachmentid=92723&d=1337450589

    Outside distance is 0.442"; inside, 0.192". (0.442 + 0.192) / 2 = 0.317. Any questions?

    -Phil
    407 x 638 - 37K
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-19 11:09
    Any questions?

    Yes, what to you use to sharpen those blades so the cut so deep into the plastic while measuring the outside distance?
  • ercoerco Posts: 20,256
    edited 2012-05-19 11:33
    Duane Degn wrote: »
    I get 7.70mm between the two sensors.

    It's always nice to give erco a good beating.

    I'm loving my beating. Thanks, Duane!
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-19 11:34
    Phil,

    What do you get if you try to measure the centers? Measure were the oval opening is at it's most forward location.

    Not that I'm admitting defeat (or any other kind of feet), but . . . if you use the inside edge / outside edge method I get 8.09mm.

    Just try measuring what looks like the center of the sensors from each other.

    What's the definition of "center of sensor"? is it the center of the two holes? The center of the sensor lens that's closest to the ground? It depends on what the meaning of is, is.

    Never might, you win, If I have to sound like a politician to win an argument (or not admit I lost it), I'd rather loose the argument.
  • ercoerco Posts: 20,256
    edited 2012-05-19 11:43
    Too bad gasoline prices are up so high. I'd love to throw some on this fire. :)
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-19 11:56
    erco wrote: »
    Too bad gasoline prices are up so high. I'd love to throw some on this fire. :)

    I think I was right once when Phil and I didn't agree about something. Oh yeah, the PropBOE can get it's power from USB.

    That's Duane 1, Phil 23.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-19 11:56
    Duane Degn wrote:
    Yes, what to you use to sharpen those blades so the cut so deep into the plastic while measuring the outside distance?
    I have a very gentle touch!

    Seriously, even with calipers, the measurement is very subjective, and I don't get the same results from both sets of holes. If I had the time and thought it important enough, I would sit the thing on top of a linear array sensor and see where the brightness centroids lay. But even that doesn't get to the meat of the OP's original question. A more significant reading could be obtained by chucking up the S2 in a CNC mill, and moving a black and white target below it in the transverse direction to see where the two sensors change state and taking the difference. My CNC mill is calibrated in inches, though, so I'm not sure that even those results would be acceptable to everyone. :)

    -Phil
  • ercoerco Posts: 20,256
    edited 2012-05-19 22:35
    Cripes, if we can't agree on a simple dimensional measurement, we'll never solve the whole religion/politics thingy.

    Can't we agree to disagree?

    Can't we decide not to decide?

    Can't we all just get along?


    erco the peacemaker
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-19 23:06
    Too bad gasoline prices are up so high. I'd love to throw some on this fire.
    But, hey, a Peacemaker by any other name:

    Colt_Peacemaker.jpg

    :)

    -Phil

    P.S. I really hope the OP got the answer he was looking for and didn't get scared away.
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2012-05-20 08:28
    Oh for heavens' sake! Who said the distance even exists in metric units? It's 0.315 by golly INCHES! center-to-center. (For all you metric weenies, that translates to 8mm.)

    -Phil

    Hey Phil, I'm at Maker Faire this weekend and while browsing around the many interesting demonstrations I noticed that more people are talking in metric. I'm not sure if it's just this crowd or if there's a change in our engineering culture. This wasn't just people referring to thousandths of an inch as a "mil" but people where talking millimeters and centimeters. I ain't kidding, Phil! You might have to change the default measurement preferences in all of your software soon, and recalibrate the Phil Big-Brain supercomputer.
  • ercoerco Posts: 20,256
    edited 2012-05-20 21:24
    Give a man an inch (or millimeter), and he thinks he's a ruler. Maxwell Smart
  • mindrobotsmindrobots Posts: 6,506
    edited 2012-05-21 07:13
    Whether using the metric system or proper units of measure, you all may be correct. The OP stated Scribbler......original or S2? Blue or (as Phil showed us) red??

    ....and speaking of Peacemakers, I'll see your Peacemaker and raise you a PEACEMAKER!

    7th_Bombardment_Wing_-_B-36_Peacemaker.jpg
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-21 07:24
    The Scribbler S1 and S2 housings are made from the same injection mold, which was modified only slightly between models. So the dimension in question here will be "color-invariant."

    -Phil
  • ercoerco Posts: 20,256
    edited 2012-05-21 07:30
    My yellow S3 is Prop-2 controlled, and comes from the future. In the future, things are much smaller. The robot's interocular distance is 1nm for nanoline following. Honest injun!
  • mindrobotsmindrobots Posts: 6,506
    edited 2012-05-21 07:34
    Once again, I bow in humbleness and awe to the wisdom of Phil.......and I'll bow to erco also (and back away slowly since amazing pyrotechnics are possible).
  • WhitWhit Posts: 4,191
    edited 2012-05-21 14:58
    erco wrote: »
    Whit, just who's side are you on? I thought you were my Dawg!

    Hey erco, ole buddy, ole pal - I am you dawg - but how can I go against PhiPi?

    It's like choosing between a BASIC Stamp 2 and a Prop - who could choose...
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