PASCO Specialty & Mfg CI-6742 User Manual

Instruction Sheet for the P ASCO Model CI-6742

012-06757B

08/98

$1.00

Motion Sensor II

Introduction

The PASCO CI-6742 Motion Sensor II is a sonar ranging device with a sensing range of 0.15 to about 8 meters. When used with an interface, the Motion Sensor II emits ultrasonic pulses and detects pulses returned as echoes from the target. The ScienceWorkshop program calculates the distance to the object from the speed of sound and half the sonic pulse round trip time. The program can also calculate velocity and acceleration from the distance and time measurements. The trigger rate for the Motion Sensor can be set in the ScienceWorkshop program to trigger as few as 5 times per second (for recording relatively slow events over large distances) or for as many as 120 times per second (for quick events such as a free-fall experiment).

The CI-6742 Motion Sensor II has several improved features, compared to the CI-6529 Motion Sensor:

ultrasonic transducer

spring clips

black phone plug (Connect to digital channels 2, 3, or 4.)

Narrow/Std. switch

target indicator LED

positioning dial

yellow phone plug (Connect to digital channels 1, 2, or 3.)

• reduced minimum distance of operation

• reduced sensitivity to false targets

• front panel LED that lights when the Motion Sensor acquires the target

• additional mounting and positioning options

• compatibility with Texas Instruments

Casio

scientific calculator-sensor interfaces

• compatibility with ULI interfaces

and

Important Operating Note: When operating in

the Std. mode, it may be necessary to tilt the transducer up 5-10 degrees for best performance, as shown.

Motion Sensor II 012-06757B

Equipment

Included:

• PASCO CI-6742 Motion Sensor II

• detachable cable with two color-coded phone plugs

Additional Equipment Required:

• computer and ScienceWorkshop 500, 700, or 750 Interface

• scientific calculator and sensor interface (Texas Instruments or Casio) and cable (PASCO part no. 514-06862) or

• ULI Interface and cable (PASCO part no. 514-06933)

Using the Motion Sensor II

1. Insert the yellow phone plug into digital channel

1 (or 1, 2, or 3 for ScienceWorkshop series 700 and 750 interfaces). Insert the black phone plug into digital channel 2 (or 2, 3, or 4 for Science Workshop series 700 and 750 interfaces).

Note: The Motion Sensor can be connected to

any two adjacent digital channels on the interface, with the yellow plug in the channel with the lower number. The yellow plug carries the transmit signal from the ScienceWorkshop interface to the sensor, and the black plug carries the return, echo signal, from the sensor to the Science Workshop interface.

2. Run the ScienceWorkshop program. In the

Experiment Setup window, set up the ScienceWorkshop interface and sensor so the Motion Sensor is connected to the correct digital channels of the interface.

Note: You can set up the Motion Sensor II in

ScienceWorkshop program (2.x series) by dragging the digital plug icon to channel 1 if the phone plugs are inserted into channels 1 and 2 on the interface box, or by doubleclicking the Motion Sensor icon in the list of sensors (3.x series).

Note: With the 700 and 750 interfaces, two

Motion Sensors may be used at the same time.

3. Set the Narrow/Standard (Std.) switch based

on your application. For experiments that involve sensing distances of 2 meters or less with highly reflective targets (such as a typical Dynamics Track experiment), set the switch to Narrow. This setting reduces sensitivity to false targets near the track and sensitivity to air track noise. For experiments that involve longer distances or poorly reflecting targets (such as match-graph experiments), set the switch to Std.

Note: When using the Std. switch setting it may

be necessary to tilt the sensor up 5-10 degrees to avoid seeing reflections from a table surface or the front of the housing as a target.

4. For most experiments, the internal calibration

in ScienceWorkshop will be adequate. However for maximum accuracy the Motion Sensor II may be calibrated as follows:

a. Double-click on the Motion Sensor icon to open the Digital Sensor Setup dialog box.

b. Aim the Motion Sensor II at a stationary target one meter away (the default calibration distance).

c. Click Calibrate. The Motion Sensor II will click a few times per second during the calibration process. The program will calculate the speed of sound based on the default calibration distance (one meter) and the round trip time of the pulses and echoes.

Note: If the Motion Sensor does not detect a

target, the Interface may stop trying to calibrate. Should this occur, realign the target of the sensor and try again.

5. Change the trigger rate (if necessary) by

clicking the up/down arrows to the right of the Trigger Rate pop-up menu, or click the popup menu and select the Trigger Rate you need. (The Trigger Rate may need to be increased from the default 20 Hz for fast events like collisions or free-fall experiments in order to achieve the necessary resolution.)

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