3B SCIENTIFIC PHYSICS U11361 User manual

3B SCIENTIFIC®PHYSICS
1
Ultrasonic Motion Sensor U11361
Instruction manual
06/09 Hh
1. Safety instructions
When in operation, the ultrasonic motion sensor
customarily generates individually audible packets of
pulses (bursts) which repeat with variable frequency.
When operated in this way the equipment is guaran-
teed to be safe.
•In the case of a fault (visible damage to the
equipment, unusual sounding bursts) the
equipment should immediately be turned off.
2. Scope of delivery
1 Ultrasonic motion sensor U11361
1 Stand rod, 120 mm long
1 Stand rod, 60 mm long
1 miniDIN 8-pin connector lead, 1 m long
1 Instruction manual for U11361
3. Description
Sensor box for measuring movements in one dimen-
sion e.g. on an air track or in free fall.
For use in conjunction with a 3B NETlogTM (U11300)
unit for making manual measurements or connected
to a computer running 3B NETlabTM (U11310) for
acquisition of measured data.
The sensor is detected automatically by the 3B NET-
logTM unit.
4. Function
The motion sensor utilises a gold-foil ultrasonic trans-
ducer and transmits packets consisting of 16 ultra-
sonic pulses (bursts). The ultrasonic sensor will detect
the echo of such signals from a (moving) object (“tar-
get”) after a minimal acoustic lag of about 1 ms –
corresponding to a distance to the object of about 15
cm. The exact distance to the object is calculated from
the time between the transmission of a signal and
detection of its echo, along with the speed of sound in
air, which is temperature dependent. For larger dis-
tances between sensor and object, the ultrasonic
transducer automatically adapts the repeat frequency
so that it is about 40 Hz for short distances and ap-
proximately 5 Hz for distances up to 10 m.

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5. Technical data
Measuring range: 0.15 m –10 m approx.
Resolution: < 5 mm
Accuracy: ± 1 %
Sensor type: Electrostatic 50 kHz -
transducer
Angle of sensor
wedge opening: 15° @ - 6 dB
Burst repeat frequency: 40 Hz to 5 Hz,
automatically adapted
according to the distance
from the object
5. Operation
•Screw the stand rod into the M6 nut provided.
•Plug the miniDIN cable into the miniDIN socket
and connect up the 3B NETlogTM unit.
•Attach the motion sensor mechanically to the
experiment set-up, e.g. in front of an air track,
under a free-falling body or in the path of a vi-
brating pendulum bob.
•Turn on the 3B NETlogTM unit and wait for it to
detect the sensor.
•Carry out measurements and evaluate them.
6. Applications
Position, speed and acceleration of moving objects.
Movements in the range of the sensor.
Detecting simple harmonic motion of a weight on a
spring.
Measuring the period of an oscillating body.
Objects moving up and down.
The bouncing of a ball.
7. Sample experiment
Uniform acceleration followed by change
of direction
Required equipment:
1 3B NETlogTM unit U11300
1 3B NETlabTM program U11310
1 Ultrasonic motion sensor U11361
1 Universal clamp U13255
1 Air track, 1.6 m U40405
1 Glider 450 g, blue U40422
1 Air-flow generator U15425
1 Conical reflector U40462
•Set up the experiment as shown in Fig. 1. Also
take note of the instructions for the air track.
•Attach the motion sensor using a universal
clamp to the rubber-band launcher on the air-
inlet side of the air track, see detailed photo-
graph, Fig. 2.
•Attach the stopper with the pulley to the other
end of the air track. Make sure that the stopper’s
spring buffer is facing along the track.
•Lower the track by adjusting the height of its
feet so that the rider moves under its own
weight towards the right-hand end of the track.
•Connect the sensor by means of its miniDIN
connector lead to analog input A or B on the 3B
NETlogTM unit.
•Wait for the 3B NETlogTM unit to detect the sen-
sor.
•Attach a conical reflector U40462 to the glider
U40422 and turn on the air track.
•Start measuring, starting with the rider moving
away from the air inlet end of the track.
•Open the experiment template for “speed meas-
urement on an air track” in 3B NETlabTM, which
includes all the necessary settings for evaluating
the measurements.
•Carry out the experiment and evaluate the re-
sults. See Fig. 3.

3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com
Subject to technical amendments
© Copyright 2009 3B Scientific GmbH
Fig. 1: Experiment set-up for measuring speed on an air track
Fig. 2: Detailed view of how the sensor box is attached to the air track
Fig. 3: Recording of a curve showing part of the motion of a glider accelerating uniformly, then changing direction