Tech Note 662 Detail

Motion Sensor Troubleshooter

Affected Products:

PS-2103a PASPORT Motion Sensor
CI-6742a Motion Sensor II

Motion Sensor Troubleshooter

PASCO Solution:

The motion sensor does not click.

PS-2103A PASPort Motion Sensor

  1. Check that the sensor has been detected by DataStudio/SPARKvue and that the Start button has been pressed.
  2. Disconnect the sensor from the PASPort interface, wait at least 10 seconds, and reconnect it to the PASPort interface. (This resets the microcontroller in the motion sensor.)

CI-6742A ScienceWorkshop Motion Sensor II

  1. Check that the leads are connected to the correct ports:
    • The yellow plug to Digital Channel 1 and the black plug to Digital Channel 2 or, if you are using a 700 or 750 interface, you can also connect the yellow and black plugs to channels 2 and 3, or channels 3 and 4 with the yellow plug in the lower-numbered channel.
  2. Check that the motion sensor has been configured in software:
    1. In DataStudio, check that a picture of the motion sensor appears in the Setup window below the channels corresponding to the channels to which it has been physically connected.
    2. When using with a PS-2159 PASPORT Digital Adapter in SPARKvue or DataStudio, a list of ScienceWorkshop sensors should appear when the sensor is connected. Select motion sensor. If you do not get a list of sensors, disconnect and reconnect the sensor to the ports of the Digital Adapter.
  3. Check that the Start button has been pressed.
  4. Replace the cable with the cable from a working sensor. If this resolves the problem, request a replacement cable.

The motion sensor clicks, but no signal is detected.

  1. Make sure the target object is located in the copper-colored region of detection below:

  2. Check that no interfering objects are located in the cone of detection between the motion sensor and the target object.
  3. Operate the range switch on the motion sensor 4-5 times. (This removes any silver sulfides that may have accumulated on the contacts.)
  4. Check that the range switch is set appropriately: The short range (cart) setting for objects that will not be travelling more than 2 meters from the sensor and the long range (person) setting for more distant objects.
  5. If the motion sensor has a detachable cable, try replacing the cable. If that fixes the problem, request a replacement from Teacher Support.
  6. Use a harder, smoother, and/or larger target. (If measuring the position of students, we recommend that they hold a white board or large hard-cover book.)
  7. Decrease the sampling rate: At the default rate of 10 Hz, the Motion Sensor can measure distance up to 8 m. The maximum distance decreases with increasing sample rate. At sample rates between 50 Hz and 250 Hz, the maximum distance is less than 2 m.
  8. If you still experience problems, please contact Teacher Support.

The signal is noisy.

  1. Decrease the sample rate. (This reduces interference from previous ultrasonic pulses by allowing more time for the pulses to decay.)
  2. Arrange the target so that the background uses a soft, irregular surface such as corrugated foam / carpet. (This reduces reflections.)
  3. If using a cart on a track, tilt the motion sensor up ~1 degree. (This reduces reflections from the track.)
  4. Use a smoother, larger target (such as a large inflatable ball).
  5. Average the signal. For example, AverageAcceleration = smooth(4, MeasuredAcceleration).
  6. If you still experience problems, please contact Teacher Support.

The distance does not change.

  1. Check that the target is located in the region of detection pictured above.
  2. Move the target object only along a path perpendicular to the face of the detector.

Creation Date: 10/1/2008
Last Modified:
Mod Summary: