A Performance Analysis System for the Sport of Bowling

More documents

Recommendations

Info

$Course Syllabus - Penn State Harrisburg Math/Computer Sciences ...$

$A Simulator for the MARIE Architecture - Penn State Harrisburg Math ...$

2.5.2 Hardware Operation Overview Figure 2-3 depicts a combination block diagram and pseudo-schematic detailing the physical connectivity of the SMARTDOT module's hardware components. The following discussion presents the theory of operation of the module's hardware, and refers to the components shown in the block diagram. The piezoelectric film sensor (T1) serves as both the "wake-up" sensor and impact detector, and is connected to the negative input (-) of an ultra-low power comparator (MAX931). Bias for the positive (+) input is provided by a voltage divider connected to the MAX931's internal 1.18V reference, with hysteresis provided through connection to the '931's "hyst" pin. The MAX931's output is connected to the asynchronous preset of a single, low-power CMOS D flip-flop (D-FF). Pressure applied to the insert is transferred to T1, generating a voltage spike that triggers the comparator, forcing the state of the D-FF to a logical '1'. The Q output of the D-FF transitions to the low (0) state, providing ground to the remainder of the module, which causes the Philips 87C752 microprocessor to "wake-up" and begin executing its program. The comparator output is also connected to an external interrupt on the '752 (labeled IMPACT_PIN) so that the microprocessor can record any subsequent activity (additional finger pressure, impact with the lane, impact with the pins, etc.) sensed by T1. With a 3.6864 MHz crystal, the 87C752 draws ~3 mAmps while running, but through use of the '752's IDLE mode between light samples, the average current drawn is reduced to less than 2 mAmps. When the '752 reaches the point where it is time to shutdown, it clocks a logical '0' into the D-FF (the 'D' input is tied to ground and the CLK pin is positive edge triggered), the Q output returns to the high (1) state, which removes ground from the microprocessor portion of the circuit, putting the module back to "sleep". The powered portion of the module (the comparator and the D-FF) draws less than 1 µA while the module is in sleep mode. The output of the TSL251 light-to-voltage converter is connected to the '752's on-board ADC (at LITE_INPUT_PIN) and the '251's ground is controlled by the microprocessor through LITE_PWR_PIN. The TSL251 draws about 800 µA when powered, and since the light waveform is sampled, rather than continuously monitored, the '752 turns off (removes ground from) the TSL251 between samples and then enters a power-reducing IDLE mode until the next sample time. The TSL251 also serves as the receiver portion of the IR communications transceiver. The transmit portion of the IR transceiver is comprised of two LED's and a resistor that limits the LED current to ~500 µA, driven by TRX_PIN. Since the transmit LEDs are only lit during a '0' pulse, and there is generally an equal distribution of 0's and 1's in a transmission, the average transmit current is ~250 µA. The 24C04 serial EEPROM stores the configurable parameters and the collected sensor data (impacts and light waveform samples) in nonvolatile memory. It draws approximately 1 mA during a write operation, and ~300 µA during a read operation. The 24C04 draws negligible current while idle (not being accessed). 18
2.6 HARDWARE/SOFTWARE INTERACTION DESIGN CONSIDERATIONS There are a number of areas where the design decisions for the hardware and the embedded software are interdependent. These issues are presented next. 2.6.1 Microprocessor Clock Frequency The clock frequency directly affects the current drawn by the microprocessor: the lower the clock frequency, the less current the 87C752 draws from the battery. The lowest standard oscillator frequency that supports the sample rate, the serial communications baud rates, and the processing demands of the application is 3.6864 MHz. The internal clock frequency for the 87C752 is 1 / 12 of the oscillator frequency, resulting in an instruction time of 3.26 µsec (307,200 instructions per second) for a 3.6864 MHz crystal. Quartz crystals and ceramic resonators are available in standard frequencies for microprocessors. Crystals easily can maintain an accuracy (over their temperature range) of 200 ppm (.03%), while ceramic resonators (cheaper and smaller) typically run in the 1- 2% range. During the feasibility phase, a crystal has been used to enhance the accuracy of the sample clock, with the hope of switching to a ceramic resonator, in combination with some clock calibration software, as part of the development phase. 2.6.2 Sampling Rate The 87C752 microprocessor contains an 8-bit ADC with a conversion time of 130 µsec (~7600 Hz) at the clock frequency of 3.6864 MHz. It is important to minimize the sample rate, since the amount of data collected directly affects the amount of external data memory required. Complicating matters, EEPROM technology has a fairly slow write speed (5-10 msec per page write), thus presenting the possibility that the rate of writing data to memory might not keep pace with the production of data to be written. Also, it is desirable to run the microprocessor in IDLE mode as much as possible, since it cuts the current draw in half, and the light sensor (TSL251) and the '752's on-board ADC can be turned off between sample times. The higher the sample rate, the more time the microprocessor must spend collecting and processing data, which shortens the life of the battery. Data must also be collected from the impact sensor, but this is a different process. An impact can occur asynchronous to the time of a light sample, with a much shorter duration than the sample period. Therefore, impact detection is interrupt driven. By limiting the stored value of the light samples to the range 0-127 (0x00-0x7F), the impact data for a sample can be stored in the high-order bit of the sample byte, thus associating each impact with the light sample during which the impact occurred. The primary factors in determining an appropriate sampling rate are the maximum angular velocity (rpms), the minimum and maximum linear velocities (ball speed), and the amount of memory available for the storage of captured data. • Maximum RPMs: According to tests conducted by the ABC (American Bowling Congress), the best bowlers, those that average greater than 210, generate an average rotational rate of about 300 rpms (5 Hz) at release. In fact, the ABC found a direct correlation between average score and angular velocity [12]. There is an upper bound on the number of revolutions the ball can make. If the ball did not skid at all, it would travel 27 inches per revolution, while revolving 19
Page 1 and 2: The Pennsylvania State University T
Page 3 and 4: TABLE OF CONTENTS Section I: Introd
Page 5 and 6: LIST OF FIGURES Figure 2-1 SMARTDOT
Page 7 and 8: SECTION I: INTRODUCTION, BACKGROUND
Page 9 and 10: eceiver that stores, processes, and
Page 11 and 12: 1.3.2 Product Development Phase The
Page 13 and 14: SECTION II: COLLECTING THE DATA - T
Page 15 and 16: 2.2 Design Constraints The feasibil
Page 17 and 18: 2.3 SENSING REQUIREMENTS The module
Page 19 and 20: Pin Deck Light Foul Line Figure 2-2
Page 21 and 22: 2.4.1 Ambient Light Sensor The ambi
Page 23: 9 28 8 RST V CC V CC 5 6 hyst 7 3 +
Page 27 and 28: 2.6.3 Baud Rate The module communic
Page 29 and 30: Configuration settings and the samp
Page 31 and 32: 2.7.5 The Ball is Rolling If the wa
Page 33 and 34: covered by the wand). When the modu
Page 35 and 36: 2.8.1 Detecting Release Detecting t
Page 37 and 38: Light Level 100 90 80 70 60 50 40 3
Page 39 and 40: By filtering the data, and then cou
Page 41 and 42: The 'F300x can write to any portion
Page 43 and 44: One possibility is to use a transfo
Page 45 and 46: 2.10 SUMMARY This portion of the re
Page 47 and 48: The ball's angular velocity increas
Page 49 and 50: Light Level 100 90 80 70 60 50 40 3
Page 51 and 52: the fundamental frequency has been
Page 53 and 54: Since the fundamental frequency and
Page 55 and 56: Figure 3-7: MASTER "Analysis" Scree
Page 57 and 58: known, the linear momentum (and thu
Page 59 and 60: In order to find the value for v 1
Page 61 and 62: 3.5 ASSUMPTIONS AND ERROR ANALYSIS
Page 63 and 64: 3.5.3 External Forces and Friction
Page 65 and 66: 3.6.1 Implementation and Performanc
Page 67 and 68: Figure 3-11a: Effects of Phase Shif
Page 69 and 70: 3.6.3 The "Perfect" Game to Analyze
Page 71 and 72: Since the change in angular velocit
Page 73 and 74: BIBLIOGRAPHY [1] United State Paten
Page 75 and 76:
APPENDIX A - SMARTDOT MODULE EMBEDD
Page 77 and 78:
Appendix A: SMARTDOT Module Embedde
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
APPENDIX B - SMARTDOT MODULE SOURCE
Page 87 and 88:
Appendix C: SMARTDOT Module Command
Page 89 and 90:
Figure C-3 Appendix C: SMARTDOT Mod
Page 91 and 92:
APPENDIX E - 300 GAME MASTER SCREEN
Page 93 and 94:
Appendix E: 300 Game Analysis Frame
Page 95 and 96:
Page 97:
show all

A Performance Analysis System for the Sport of Bowling

Create successful ePaper yourself

Delete template?

Save as template?