PASCO PS-2103A Motion Sensor - Manual (Page 4)

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M o t i o n S e n s o r PS - 2 1 0 3 A
4
Troubleshooting
If the Motion Sensor fails to perform satisfactorily, try these
steps:
• Ensure that the target object is no closer than 15 cm.
• Switch the range switch to the other setting.
• Adjust the aim left, right, up, or down. In some cases the
Motion Sensor works best when it is aimed slightly to the
side or above the target in order to exclude interfering
objects.
• Improve the target by adding a larger or harder surface to
reflect ultrasound. A small object can be a better reflector
than large object if it has a harder surface.
• Remove interfering objects near the target object or sensor.
• Increase or decrease the sample rate.
Theory of Operation
The Motion Sensor uses an electrostatic transducer as both a
speaker and a microphone. For each sample, the transducer trans-
mits a burst of 16 ultrasonic pluses with a frequency of about 49
kHz. This burst of pulses can be heard as a single click. The ultra-
sonic pulses reflect off an object and return to the sensor. The tar-
get indicator on the sensor flashes when the transducer detects an
echo.
Sound intensity decreases with distance; to compensate, the sen-
sor increases the gain of the receiver amplifier as it waits for the
echo. The increased gain allows the sensor to detect an object up
to 8 m away. The lower gain at the beginning of the cycle reduces
the circuit's sensitivity to echoes from false targets.
The sensor measures the time between the trigger rising edge and
the echo rising edge. It uses this time and the speed of sound to
calculate the distance to the object. To determine velocity, it uses
consecutive position measurements to calculate the rate of
change of position. Similarly, it determines acceleration using
consecutive velocity measurements.
Specifications
Technical Support
For assistance with any PASCO product, contact PASCO at:
Limited Warranty For a description of the product warranty, see the
PASCO catalog.
Copyright
The PASCO scientific 012-09625A Motion Sensor Instruction
Sheet is copyrighted with all rights reserved. Permission is granted to
non-profit educational institutions for reproduction of any part of this man-
ual, providing the reproductions are used only in their laboratories and
classrooms, and are not sold for profit. Reproduction under any other cir-
cumstances, without the written consent of PASCO scientific, is prohibited.
Trademarks
PASCO, PASCO scientific, DataStudio, and
ScienceWorkshop are trademarks or registered trademarks of PASCO sci-
entific, in the United States and/or in other countries. All other brands,
products, or service names are or may be trademarks or service marks of,
and are used to identify, products or services of, their respective owners.
For more information visit www.pasco.com/legal.
Minimum Range 15 cm
Maximum Range 8 m
Transducer Rotation 360°
Range Settings Short Range: for distance measurement up
to 2 m with improved rejection of false target
signals and air-track noise
Long Range: for distance measurement up
to 8 m
Mounting Options • On rod up to 12.7 mm diameter
• Directly to PASCO dynamics tracks
• On table top
Address: PASCO scientific
10101 Foothills Blvd.
Roseville, CA 95747-7100
Phone: 916-786-3800 (worldwide)
800-772-8700 (U.S.)
Fax: (916) 786-7565
Web: www.pasco.com
Email: [email protected]