A Performance Analysis System for the Sport of Bowling

2.7.2 Start-Up
The SMARTDOT module spends the vast majority of its time in an ultra-low power sleep
mode, which draws less than 1 µAmp. Finger pressure applied to the insert wakes the
module from its sleep. Since the bowler's finger must still be in the insert immediately
after start-up, if SMARTDOT detects too much light at start-up, the release is presumed to
be invalid (for instance, caused by another ball striking it on the ball return), and the
module shuts down (goes back to sleep).
If it is dark enough after start-up, SMARTDOT continues sampling the ambient light
level, waiting for the release of the ball (indicated by the measured light level exceeding a
configurable "release" level). The release process takes several seconds, while the
bowler picks up the ball from the ball return and subsequently delivers it to the lane
during their approach. If release is not detected within one second of activation, the
module shuts down. Since the bowler grips the inserts throughout their approach, the
module may experience several "false" start-ups before the actual release occurs. Refer
to Figure A-1a (Start-Up Task Flowchart) for the sequence of events at module start-up.
2.7.3 Pre-Sampling
As part of the actual release, the bowler applies significant pressure to the inserts
immediately before release. The module is again activated (several hundred milliseconds
before release), giving SMARTDOT sufficient time to see the ambient light release point.
Since the module detected a valid pre-release light level at start-up, it looks for the
release light level for up to one second. While waiting for release, the module stores the
pre-release light samples in an 8-byte circular buffer. This "pre-sampling" allows the
MASTER application to identify the precise moment of release. See Figure A-1b (Pre-
Sampling Task Flowchart) for the pre-sampling sequence of events.
The waveform is sampled at 240 Hz, but the sample data is collected and stored at a 120
Hz rate. In order to cancel the effects of the 120 Hz AC ripple superimposed on the
waveform by the overhead fluorescent lights, two consecutive 240 Hz samples are
averaged together to yield a single 120 Hz sample. The maximum stored sample value is
clipped to 127 (0x7F) so that the high-order bit of each sample is available for storing the
impact status for that sample. Refer to Figure A-2 (Light Sample ISR Flowchart).
2.7.4 Waveform Discrimination and Validation
The SMARTDOT module always runs in one of two major operational states: it samples,
validates, and stores the ambient light waveform; or it communicates with the COMM
wand. While the module samples and stores the waveform, it also executes a routine that
discriminates between waveforms that result from the ball rolling down the lane, the
MASTER attempting to make contact, and spurious activations.
After detecting the actual release of the ball, the module continues to sample the
waveform and collect data in its 8-byte RAM sample buffer (the same one used for
storing the pre-samples), transferring the buffer contents to the active scratch pad in
external EEPROM while scanning the sampled data for a pattern consistent with the ball
rolling down the lane. If the presence of a "valid" waveform (one that looks like the ball
is rolling) is not detected within 600 msecs (72 samples plus the 8 pre-samples) following
release, the module automatically switches from sampling the waveform to its
communication routines, and attempts to contact the COMM wand. Refer to Figure A-3
(Sampling Task Flowchart) and Figure A-4 (Discrimination Task Flowchart).
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