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What does it mean ? — Parallax Forums

What does it mean ?

Cau2DaNangCau2DaNang Posts: 20
edited 2006-02-22 16:02 in BASIC Stamp
· Hi all

· I'm using PING))) Sensor. In the datasheet, I saw the testing data of PING))) Sensor. Can anyone please explain for me what this result graph mean ?
Test1.JPG
465 x 522 - 30K
Test2.JPG
490 x 522 - 31K

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-22 15:01
    We used two types of target: a cylinder (soda can) and a flat panel. The nature of the curved surface of the cylinder object causes it to reflect sounds back further off-axis close in, but not so much at distance. Note how the flat object is detected at a greater distance because it reflects back more of the sonic pulse to the detector.

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    Jon Williams
    Applications Engineer, Parallax
  • Cau2DaNangCau2DaNang Posts: 20
    edited 2006-02-22 15:06
    Thanks for your reply, Mr William. Can you please let me know the mean of value 0' 1' 2' ... in the horizontal axis of graph and 10, 20 , 30 ... in the curve ?
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2006-02-22 15:36
    Cau2DaNang -

    The single quotation mark is an abbreviation for FEET; thus it represents the measurement of 0 feet, 1 foot, 2 feet, etc. in distance.

    Regards,

    Bruce Bates

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  • Cau2DaNangCau2DaNang Posts: 20
    edited 2006-02-22 15:42
    Yes I know that ... but as Mr William's explanation: "The nature of the curved surface of the cylinder object causes it to reflect sounds back further off-axis close in, but not so much at distance". However, I see in the graph that the distance (in feet) in cylinder testing is further than in flat object.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-22 15:54
    How are you seeing that? In the first graph (cylinder) the max distance is about 7.5 feet; inthe second graph (flat surface) the max distance is 10 feet. What this demostrates is that the Ping can detect flat objects at a greater distance. The reason for this is the path of the reflections -- with the cylinder some of the waves are reflected away, instead of back to the Ping (like a stealth airplane).

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    Jon Williams
    Applications Engineer, Parallax
  • Cau2DaNangCau2DaNang Posts: 20
    edited 2006-02-22 15:59
    Oh ok. I see. How's about the degree, Mr William ?
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-22 16:02
    What about it? The graph shows that the cylinder can be detected farther off-axis; again, this is due to the cylinder spreading the reflections so some of them will be at the right angle to come back to the Ping (whereas at the same angle the flat object would reflect them away).

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    Jon Williams
    Applications Engineer, Parallax
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