Motion Sensor II • CI-6742A

PASCO’s digital ScienceWorkshop Motion Sensor II is used to measure position, velocity and acceleration. Ultrasonic pulse-ranging technology has a switch-selectable Standard Beam or Narrow Beam to reject false signals and produce cleaner data. The Motion Sensor sits firmly on a desktop or easily mounts to a rod stand or PASCO Dynamics Track.

The “Narrow Beam” setting, for distances from 15 cm to 2 m, provides cleaner data by rejecting false target signals or ignoring air track noise. Use "Standard" setting for distances from 15 cm to 8 m.

Shorter Dead Zone:

• Detects targets as close as 15 cm from the sensor increasing the effective length of a dynamics track (other motion sensors have a dead zone of 42 cm).

False Target Rejection Circuit:

• Reduces false signals from objects near the target's path of motion, giving cleaner data.

How It Works

When triggered, the electrostatic transducer in the motion sensor transmits a burst of 16 ultrasonic pulses with a frequency of about 49 kHz. The ultrasonic pulses reflect off an object and return to the sensor. The target indicator on the sensor flashes when the transducer detects an echo.

The interface measures the time between trigger rising edge and the echo rising edge. DataStudio uses this time and the speed of sound to calculate the distance to the object. To determine velocity, DataStudio uses consecutive position measurements to calculate the rate of change of position. Similarly with acceleration.