近年來，台灣在針對交通安全的改善越來越進步，在法規上也做了很多調整，胎紋深度也設立了相關的法規，而本研究透過超聲波測距方式，藉由Arduino Mega 2560板做為實驗平台，搭配HC-SR04超聲波測距模組去做距離的測量，經由一組測距模組以超聲波測出胎面到感知器的距離，再透過另一組HC-SR04量測超聲波測距模組到胎溝之間的距離，由兩組感測器之距離差去計算出胎溝的深度，進一步透過溫度與濕度感知器量測到的數據去校正，得到更精確的胎紋深度，使其量測精準度控制在±0.2mm以內，以便改善駕駛與用路人的安全。

Recently traffic rules have gradually improved and changed traffic behavior and patterns in Taiwan. Legal provisions about tire tread depth were also established. Research has been conducted using ultrasound to measure tread depth using the Arduino Mega 2560 board with HC-SR04 ultrasonic distance sensor. The distance between the tread and sensor is measured using one sets of distance measuring modules. The distance between the sensor and the tire groove is measured by the other set of HC-SR04 modules. The tread depth is calculated by the difference in measurement between the two sets of sensors. A temperature and humidity sensor measures data to calibrate more accurate tread depth distance. The measurement accuracy control is within ± 0.2mm. This device improves the safety of drivers and passengers.

ABSTRCT(CHINESE) i
ABSTRCT(ENGLISH) ii
ACKNOWLEDGEMENT iii
LIST OF TABLES vi
LIST OF FIGURES vii
LIST OF SYMBOLS ix

CHAPTER 1
INTRODUCTION
1-1 The History of the Ultrasonic Distance Measurement 1
1-2 Research Motivation 2
1-3 Solution 3

CHAPTER 2
THEORY OF ULTRASONIC MEASUREMENT
2-1 Speed of Sound 5
2-2 Speed of Sound in Ideal Gases and Air 8
2-3 Normalization of Beam Radius and Distance 8
2-4 Extinction Distance of Sound 11
2-5 The Curvature Radius Effect on Precision 12

CHAPTER 3
ARDUINO APPLICATION AND DEVELOPMENT
3-1 The HC-SR04 Ultrasonic Module 13
3-2 Blind Zone 16
3-3 Frequency of Ultrasonic Transducer 17

CHAPTER 4
RESULTS OF TREAD DEPTH MEASUREMENT
4-1 Introduction of Experiment 19
4-1-1 Distance Measurement in Different Environments 25
4-1-2 Maxxis Bravo Series HP-600 Tire - 215/65/R16 (Wear) 28
4-1-3Continental Cross Contact LX Radial Tire Test - 215/70R16 30
4-2 Experimental Results 33

CHAPTER 5
CONCLUSIONS 43
REFERENCES 44
APPENDIX 46

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