28029 Parallax Inc, 28029 Datasheet - Page 57

• Manufacturer Part Number: 28029
• Description: KIT PARTS SMART SENSORS W/TEXT
• Manufacturer: Parallax Inc

Specifications of 28029

• Accessory Type: Parts Kit
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: BASIC Stamp® or Javelin Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 28029PAR

In addition, as Ken Gracey of Parallax Inc. discovered during a classroom demonstration
at his son’s school, some objects with soft, irregular surfaces (such as stuffed animals)
will absorb rather than reflect sound and therefore can be difficult for the Ping))) sensor
to detect. Objects with smooth surfaces that readily reflect sound are easier for the sensor
to detect.
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Try pointing the Ping))) sensor at various objects that are different distances
away. What's the largest value the Ping))) sensor returns? How close do you
have to get to the object before the time measurements start to decrease?
Try standing one meter away from the wall, and point the Ping))) sensor at it,
and record the measurement. Next, try pointing the Ping))) sensor at the wall at
different angles, as shown in Figure 2-5. Do the values change? At what angle
does the Ping))) sensor cease to detect the wall?
Try hanging various objects from the ceiling at about 1.5 meters from the Ping)))
sensor. How small can the object be? Does shape or angle matter? Does the
size requirement change at 0.5 meters?
Try detecting objects of similar size but made from different materials, such as a
cardboard shoebox and a fuzzy slipper, to see if you have a smaller effective
range with sound-absorbing objects. Can you find any objects invisible to the
Ping))) sensor? How about a wad of cotton balls, or of tulle netting?
Chapter 2: The Ping))) Ultrasonic Sensor · Page 45
Figure 2-5
Determining the
Minimum Angle of
Detection