8
G
ETTING
S
TARTED WITH THE
CBR 2™
S
ONIC
M
OTION
D
ETECTOR
©
1997,
2004,
2006
T
EXAS
I
NSTRUMENTS
I
NCORPORATED
Hints for effective data collection
(cont.)
EasyData settings (for TI-83, TI-83 Plus, TI-84, and TI-84 Plus users only)
Setup data collection for Time Graph
Experiment length is the total time in seconds to complete all sampling. It’s determined by
the number of samples multiplied by the sample interval.
Enter a number between 0.05 (for very fast moving objects) and 0.5 seconds (for very slow
moving objects).
Note:
See “To set up the calculator for data collection” on page 12 for detailed information
about how to change settings.
Menu name
Description
Default setting
Sample Interval
Measures time between samples in seconds.
0.05
Number of Samples
Total number of samples to collect.
100
Experiment Length
Length of the experiment in seconds.
5
Starting and stopping
To start sampling, select
Start
(press
q
). Sampling will automatically stop when the
number of samples set in the
Time Graph Settings
menu is reached. The
CBR 2™
motion
detector will then display a graph of the sampled data on the graphing calculator.
To stop sampling before it automatically stops, select
Stop
(press and hold
q
) at any time
during the sampling process. When sampling stops, a graph of the sampled data is
displayed.
Noise—what is it and how do you get rid of it?
When the
CBR 2™
motion detector receives signals reflected from objects other than the
primary target, the plot shows erratic data points (noise spikes) that do not conform to the
general pattern of the plot. To minimize noise:
0
Make sure the
CBR 2™
motion detector is pointed directly at the target. Try adjusting the
sensor head while viewing live data on the home-screen meter. Make sure the reading
you receive is appropriate before starting an activity or experiment.
0
Try to sample in a clutter-free space (see the
clear zone
drawing on page 7).
0
Choose a larger, more reflective object or move the object closer to the
CBR 2™
(but
farther than 15 centimeters).
0
When using more than one
CBR 2™
motion detector in a room, one group should
complete a sample before the next group begins their sample.
0
Try moving the sensitivity switch to the Track position to reduce the sensitivity of the
sensor.
