3B Scientific Ultrasonic Motion Sensor - 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 NETlog TM (U11300)
unit for making manual measurements or connected
to a computer running 3B NETlab
TM (U11310) for
acquisition of measured data.
The sensor is detected automatically by the 3B NET-
log
TM 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.