©
1997,
2004,
2006
T
EXAS
I
NSTRUMENTS
I
NCORPORATED
G
ETTING
S
TARTED WITH THE
CBR 2™
S
ONIC
M
OTION
D
ETECTOR
9
Hints for effective data collection
(cont.)
Speed of sound
The approximate distance to the object is calculated by assuming a nominal speed of sound.
However, actual speed of sound varies with several factors, most notably the air
temperature.
The
CBR 2™
motion detector has a built-in temperature sensor to automatically compensate
for changes in the speed of sound due to the temperature of the surrounding air. The
temperature conversion from 0° to 40° Celsius, at standard pressure, is fairly linear at about
+0.6 meters/second per degree Celsius. The speed of sound increases from about 331
meters/second at 0° Celsius to about 355 meters/second at 40° Celsius. These speeds
assume a relative humidity of 35% (dry air).
When using the EasyData App with the
CBR 2™
motion detector, this temperature
compensation will take place when collecting motion data. The sensor is located underneath
the holes on the back of the
CBR 2™
motion detector; therefore, when collecting data, do
not cover these holes with something that is of a different temperature from the
surrounding ambient temperature.
Using the CBR 2™ sonic motion detector without the EasyData application
You can use the
CBR 2™
unit as a sonic motion detector with a
CBL 2™
system or with
programs other than EasyData.
Using the I/O unit-to-unit cable, the
CBR 2™
motion detector can be used with graphing
calculators that do not have the EasyData App installed but do have the
CBL/CBR
App and/or
the RANGER program. The
CBR 2™
motion detector will provide the same functionality as a
CBR™
motion detector when sample data is collected using the
CBL/CBR
App and/or the
RANGER program.
The
CBL/CBR
App can be used on most older TI-83 Plus calculators. The
CBL/CBR
App is
available for downloading at education.ti.com and allows you to collect motion data using
the I/O unit-to-unit cable on the
CBR 2™
motion detector.
The RANGER program, which is part of the
CBL/CBR
App and available for other calculators,
allows you to collect motion data using the I/O unit-to-unit cable. Many TI Explorations
workbooks use the RANGER program. (The RANGER program is the only program available
for use with the TI-89, TI-92 Plus, TI-89 Titanium, and Voyage™ 200 to perform activities
like Ball Bounce and Graph Match.)
You can also use
CBR 2™
unit
as a motion sensor with your
CBL 2™
data collection device.
Use the DataMate App that comes with the
CBL 2™
system to operate the
CBR 2™
motion
detector
through a
CBL 2™
system. A special
CBL-
to
-CBR
cable is required to use this system.
For more information about this cable visit the TI webstore at education.ti.com.
