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标题: Arduino平台软硬件原理及使用——开源库的使用 [打印本页]

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作者: 李优秀    时间: 2024-10-15 23:56
标题: Arduino平台软硬件原理及使用——开源库的使用
文章目录：
一、库文件的下载及导入
二、库文件源代码分析
三、库文件应用举例
  一、库文件的下载及导入

有关arduino开源库的导入有两种方案：
1.第一种方案需要借助arduino.cc网站来举行查询下载，然后在Arduino软件中举行导入。
2.第二种方案则只需要使用较新版本的Arduino软件（2.2版本之后），在软件中可以直接搜索并导入开源库。
1.在Arduino.cc举行导入库

首先在网页地点框直接输入arduino.cc便可进入网站：

然后点击上方【DOCUMENTATION】选项：

在此页面点击左侧【Libraries】选项，便可进入官方收录的库文件页面：

选择要用的库文件的类目，这里以【display】为例：

然后点击具体的库文件，以【LiquidCrystal】为例：

进入库文件下载目录后，直接点击要用的版本号即可直接下载。
下载完成后如果不是压缩包，最好压缩成zip文件：

末了打开Arduino软件，选择【项目】-【导入库】-【添加.ZIP库】然后选择对应的zip文件即可导入乐成。
2.使用Arduino软件导入库

上述方案较为复杂，所以建议使用较新版本的Arduino软件直接导入库：

在此版本的软件中直接点选左侧的“册本”样式的图标（其表示为库文件），然后直接在搜索框查找要使用的库文件名，选择对应库文件及版本点击安装即可。
这种方案则最为简洁，当然有些时间要使用的库在软件中查询不到，此时就需要接纳第一种方案举行导入。
2、库文件源代码分析

如上图所示，一般库文件中会有如上几个文件（会存在些许不同）。
1.示例程序的使用

example文件即为【示例】，这里面会有开源文件贡献者编写的几个示例程序，用于资助学习者理解库的使用：

当然只要将库文件导入过Arduino中，也可以在Arduino软件中打开相应的示例程序：

2.【.h文件】及【.cpp】文件分析

在【src】文件夹中存在以下两个文件：
【.h】后缀我们称之为头文件，【.cpp】后缀我们称之为源文件

头文件通常包含类声明、函数原型、宏定义和全局变量声明等。它们的目的是提供一种方式来共享代码，并确保在多个源文件中使用一致的声明：

1. /*
2.   HCSR04 - Library for arduino, for HC-SR04 ultrasonic distance sensor.
3.   Created by Dirk Sarodnick, 2020.
4. */
6. #ifndef HCSR04_H
7. #define HCSR04_H
9. #include "Arduino.h"
11. #define HCSR04_INVALID_RESULT  -1;
12. #define HCSR04_NO_TRIGGER      -2;
13. #define HCSR04_NO_ECHO         -3;
15. class HCSR04Sensor {
16.         public:
17.                 HCSR04Sensor();
18.                 ~HCSR04Sensor();
20.                 typedef enum eUltraSonicUnlock {
21.                         unlockSkip = 0,
22.                         unlockMaybe = 1,
23.                         unlockForced = 2
24.                 } eUltraSonicUnlock_t;
25.                
26.                 void begin(uint8_t triggerPin, uint8_t echoPin) { begin(triggerPin, new uint8_t[1]{ echoPin }, 1); }
27.                 void begin(uint8_t triggerPin, uint8_t* echoPins, uint8_t echoCount) { begin(triggerPin, echoPins, echoCount, 100000, eUltraSonicUnlock_t::unlockSkip); }
28.                 void begin(uint8_t triggerPin, uint8_t echoPin, uint32_t timeout, eUltraSonicUnlock_t unlock) { begin(triggerPin, new uint8_t[1]{ echoPin }, 1, timeout, unlock); }
29.                 void begin(uint8_t triggerPin, uint8_t* echoPins, uint8_t echoCount, uint32_t timeout, eUltraSonicUnlock_t unlock) { begin(triggerPin, echoPins, echoCount, timeout, 10, 10, unlock); }
30.                 void begin(uint8_t triggerPin, uint8_t* echoPins, uint8_t echoCount, uint32_t timeout, uint16_t triggerTime, uint16_t triggerWait, eUltraSonicUnlock_t unlock);
31.                 void end();
32.                
33.                 long* measureMicroseconds() { measureMicroseconds(lastMicroseconds); return lastMicroseconds; }
34.                 void measureMicroseconds(long* results);
36.                 double* measureDistanceMm() { measureDistanceMm(defaultTemperature, lastDistances); return lastDistances; }
37.                 void measureDistanceMm(double* results) { measureDistanceMm(defaultTemperature, results == NULL ? lastDistances : results); }
38.                 double* measureDistanceMm(float temperature) { measureDistanceMm(temperature, lastDistances); return lastDistances; }
39.                 void measureDistanceMm(float temperature, double* results);
41.                 double* measureDistanceCm() { measureDistanceCm(defaultTemperature, lastDistances); return lastDistances; }
42.                 void measureDistanceCm(double* results) { measureDistanceCm(defaultTemperature, results == NULL ? lastDistances : results); }
43.                 double* measureDistanceCm(float temperature) { measureDistanceCm(temperature, lastDistances); return lastDistances; }
44.                 void measureDistanceCm(float temperature, double* results);
46.                 double* measureDistanceIn() { measureDistanceIn(defaultTemperature, lastDistances); return lastDistances; }
47.                 void measureDistanceIn(double* results) { measureDistanceIn(defaultTemperature, results == NULL ? lastDistances : results); }
48.                 double* measureDistanceIn(float temperature) { measureDistanceIn(temperature, lastDistances); return lastDistances; }
49.                 void measureDistanceIn(float temperature, double* results);
50.                
51.                 static void triggerInterrupt0(void);
52.                 static void triggerInterrupt1(void);
53.                 static void triggerInterrupt2(void);
54.                 static void triggerInterrupt3(void);
55.                 static void triggerInterrupt4(void);
56.                 static void triggerInterrupt5(void);
57.                 static void triggerInterrupt6(void);
58.                 static void triggerInterrupt7(void);
59.                 static void triggerInterrupt8(void);
60.                 static void triggerInterrupt9(void);
61.                
62.                 static void echoInterrupt0(void);
63.                 static void echoInterrupt1(void);
64.                 static void echoInterrupt2(void);
65.                 static void echoInterrupt3(void);
66.                 static void echoInterrupt4(void);
67.                 static void echoInterrupt5(void);
68.                 static void echoInterrupt6(void);
69.                 static void echoInterrupt7(void);
70.                 static void echoInterrupt8(void);
71.                 static void echoInterrupt9(void);
72.        
73.         private:
74.                 float defaultTemperature = 19.307;
75.                 long* lastMicroseconds;
76.                 double* lastDistances;
78.                 uint32_t timeout;
79.                 uint16_t triggerTime = 10; // HC-SR04 needs at least 10�s trigger. Others may need longer trigger pulses.
80.                 uint16_t triggerWait = 10; // HC-SR04 sends its signal about 200�s. We only wait a small amount to reduce interference, but to not miss anything on slower clock speeds.
81.                 volatile uint8_t triggerPin;
82.                 volatile unsigned long* volatile triggerTimes;
83.                
84.                 uint8_t echoCount;
85.                 volatile int16_t* volatile echoStages;
86.                 volatile int16_t* volatile echoInts;
87.                 volatile int16_t* volatile echoPorts;
88.                 volatile unsigned long* volatile echoTimes;
89.                
90.                 void triggerInterrupt(uint8_t);
91.                 void echoInterrupt(uint8_t);
92.                 void unlockSensors(eUltraSonicUnlock_t, uint8_t*);
93. };
95. extern HCSR04Sensor HCSR04;
97. #endif // HCSR04_H

复制代码

源文件包含了实现代码，即函数和方法的定义。它们通常包含与头文件对应的实现：

1. /*
2.   HCSR04 - Library for arduino, for HC-SR04 ultrasonic distance sensor.
3.   Created by Dirk Sarodnick, 2020.
4. */
6. #include "Arduino.h"
7. #include "HCSR04.h"
9. HCSR04Sensor::HCSR04Sensor() {}
10. HCSR04Sensor::~HCSR04Sensor() { this->end(); }
12. void HCSR04Sensor::begin(uint8_t triggerPin, uint8_t* echoPins, uint8_t echoCount, uint32_t timeout, uint16_t triggerTime, uint16_t triggerWait, eUltraSonicUnlock_t unlock) {
13.         if (this->echoCount != echoCount) this->end();
14.        
15.         this->triggerPin = triggerPin;
16.         pinMode(triggerPin, OUTPUT);
18.         this->timeout = timeout;
19.         this->triggerTime = triggerTime;
20.         this->triggerWait = triggerWait;
21.         this->echoCount = echoCount;
22.        
23.         if (this->lastMicroseconds == NULL) this->lastMicroseconds = new long[echoCount];
24.         if (this->lastDistances == NULL) this->lastDistances = new double[echoCount];
25.        
26.         if (this->triggerTimes == NULL) this->triggerTimes = new unsigned long[echoCount];
27.         if (this->echoTimes == NULL) this->echoTimes = new unsigned long[echoCount];
29.         if (this->echoStages == NULL) this->echoStages = new int16_t[echoCount];
30.         if (this->echoInts == NULL) this->echoInts = new int16_t[echoCount];
31.         if (this->echoPorts == NULL) this->echoPorts = new int16_t[echoCount];
33.         for (uint8_t i = 0; i < this->echoCount; i++) {
34.                 this->triggerTimes[i] = 0;
35.                 this->echoTimes[i] = 0;
37.                 int16_t interrupt = digitalPinToInterrupt(echoPins[i]);
38.                 if (interrupt == NOT_AN_INTERRUPT) {
39.                         this->echoStages[i] = -1;
40.                         this->echoInts[i] = -1;
41.                         this->echoPorts[i] = echoPins[i];
42.                 } else {
43.                         this->echoStages[i] = 0;
44.                         this->echoInts[i] = interrupt;
45.                         this->echoPorts[i] = -1;
46.                 }
48.                 pinMode(echoPins[i], INPUT);
49.         }
50.        
51.         // Unlock sensors that are possibly in a locked state, if this feature is enabled.
52.         this->unlockSensors(unlock, echoPins);
53. }
55. void HCSR04Sensor::end() {
56.         if (this->lastMicroseconds != NULL) delete []this->lastMicroseconds;
57.         if (this->lastDistances != NULL) delete []this->lastDistances;
58.         if (this->triggerTimes != NULL) delete []this->triggerTimes;
59.         if (this->echoTimes != NULL) delete []this->echoTimes;
60.        
61.         if (this->echoPorts != NULL) delete []this->echoPorts;
62.         if (this->echoInts != NULL) delete []this->echoInts;
63.         if (this->echoStages != NULL) delete []this->echoStages;
64.        
65.         this->lastMicroseconds = NULL;
66.         this->lastDistances = NULL;
67.         this->triggerTimes = NULL;
68.         this->echoTimes = NULL;
69.         this->echoPorts = NULL;
70.         this->echoInts = NULL;
71.         this->echoStages = NULL;
72. }
74. void HCSR04Sensor::measureMicroseconds(long* results) {
75.         if (results == NULL) results = this->lastMicroseconds;
77.         bool finished = true;
78.         bool waiting = true;
79.         unsigned long startMicros = micros();
80.         unsigned long currentMicros = 0;
81.         unsigned long elapsedMicros = 0;
83.         // Make sure that trigger pin is LOW.
84.         digitalWrite(triggerPin, LOW);
85.         delayMicroseconds(4);
86.        
87.         // Hold trigger HIGH for 10 microseconds (default), which signals the sensor to measure distance.
88.         digitalWrite(triggerPin, HIGH);
89.         delayMicroseconds(this->triggerTime);
91.         // Set trigger LOW again and wait to give the sensor time for sending the signal without interference
92.         digitalWrite(triggerPin, LOW);
93.         delayMicroseconds(this->triggerWait);
94.        
95.         // Attach interrupts to echo pins for the starting point
96.         for (uint8_t i = 0; i < this->echoCount; i++) {
97.                 if (this->echoInts[i] >= 0 && this->echoStages[i] == 0) {
98.                         this->echoStages[i] = 1;
99.                         switch (i) {
100.                                 case 0: attachInterrupt(this->echoInts[i], &triggerInterrupt0, RISING); break;
101.                                 case 1: attachInterrupt(this->echoInts[i], &triggerInterrupt1, RISING); break;
102.                                 case 2: attachInterrupt(this->echoInts[i], &triggerInterrupt2, RISING); break;
103.                                 case 3: attachInterrupt(this->echoInts[i], &triggerInterrupt3, RISING); break;
104.                                 case 4: attachInterrupt(this->echoInts[i], &triggerInterrupt4, RISING); break;
105.                                 case 5: attachInterrupt(this->echoInts[i], &triggerInterrupt5, RISING); break;
106.                                 case 6: attachInterrupt(this->echoInts[i], &triggerInterrupt6, RISING); break;
107.                                 case 7: attachInterrupt(this->echoInts[i], &triggerInterrupt7, RISING); break;
108.                                 case 8: attachInterrupt(this->echoInts[i], &triggerInterrupt8, RISING); break;
109.                                 case 9: attachInterrupt(this->echoInts[i], &triggerInterrupt9, RISING); break;
110.                         }
111.                 }
112.         }
113.        
114.         // Wait until all echos are returned or timed out.
115.         while(true) {
116.                 delayMicroseconds(1);
117.                
118.                 finished = true;
119.                 waiting = true;
120.                 currentMicros = micros();
121.                 elapsedMicros = currentMicros - startMicros;
123.                 for (uint8_t i = 0; i < this->echoCount; i++) {
124.                         waiting &= elapsedMicros < this->timeout || (this->triggerTimes[i] > 0 && this->echoTimes[i] == 0 && (currentMicros - this->triggerTimes[i]) < this->timeout);
126.                         if (this->echoPorts[i] >= 0 && this->triggerTimes[i] == 0) {
127.                                 if (digitalRead(this->echoPorts[i]) == HIGH) this->triggerTimes[i] = micros();
128.                         }
130.                         if (this->triggerTimes[i] > 0 || !waiting) {
131.                                 if (this->echoInts[i] >= 0 && (this->echoStages[i] == 1 || !waiting)) {
132.                                         if (this->echoStages[i] == 1) this->echoStages[i] = 2;
133.                                         detachInterrupt(this->echoInts[i]);
134.                                 }
135.                         } else finished &= false;
137.                         if (this->echoInts[i] >= 0 && this->triggerTimes[i] > 0 && this->echoStages[i] == 2 && waiting) {
138.                                 this->echoStages[i] = 3;
139.                                 switch (i) {
140.                                         case 0: attachInterrupt(this->echoInts[i], &echoInterrupt0, FALLING); break;
141.                                         case 1: attachInterrupt(this->echoInts[i], &echoInterrupt1, FALLING); break;
142.                                         case 2: attachInterrupt(this->echoInts[i], &echoInterrupt2, FALLING); break;
143.                                         case 3: attachInterrupt(this->echoInts[i], &echoInterrupt3, FALLING); break;
144.                                         case 4: attachInterrupt(this->echoInts[i], &echoInterrupt4, FALLING); break;
145.                                         case 5: attachInterrupt(this->echoInts[i], &echoInterrupt5, FALLING); break;
146.                                         case 6: attachInterrupt(this->echoInts[i], &echoInterrupt6, FALLING); break;
147.                                         case 7: attachInterrupt(this->echoInts[i], &echoInterrupt7, FALLING); break;
148.                                         case 8: attachInterrupt(this->echoInts[i], &echoInterrupt8, FALLING); break;
149.                                         case 9: attachInterrupt(this->echoInts[i], &echoInterrupt9, FALLING); break;
150.                                 }
151.                         }
153.                         if (this->echoPorts[i] >= 0 && this->triggerTimes[i] > 0 && this->echoTimes[i] == 0) {
154.                                 if (digitalRead(this->echoPorts[i]) == LOW) this->echoTimes[i] = micros();
155.                         }
156.                        
157.                         if ((this->triggerTimes[i] > 0 && this->echoTimes[i] > 0) || !waiting) {
158.                                 if (this->echoInts[i] >= 0 && (this->echoStages[i] == 3 || !waiting)) {
159.                                         if (this->echoStages[i] == 3) this->echoStages[i] = 4;
160.                                         detachInterrupt(this->echoInts[i]);
161.                                 }
162.                         } else finished &= false;
163.                 }
164.                
165.                 if (!waiting || finished) break;
166.         }
167.        
168.         // Determine the durations of each sensor.
169.         for (uint8_t i = 0; i < this->echoCount; i++) {
170.                 if (this->echoInts[i] >= 0) this->echoStages[i] = 0;
171.                 if (this->triggerTimes[i] > 0 && this->echoTimes[i] > 0) {
172.                         long resultTime = this->echoTimes[i] - this->triggerTimes[i];
173.                         results[i] = resultTime > 0 ? resultTime : HCSR04_INVALID_RESULT;
174.                 } else if (this->triggerTimes[i] > 0) {
175.                         results[i] = HCSR04_NO_ECHO;
176.                 } else {
177.                         results[i] = HCSR04_NO_TRIGGER;
178.                 }
180.                 this->triggerTimes[i] = 0;
181.                 this->echoTimes[i] = 0;
182.         }
183. }
185. void HCSR04Sensor::measureDistanceMm(float temperature, double* results) {
186.         if (results == NULL) results = this->lastDistances;
188.         double speedOfSoundInMmPerMs = (331.3 + 0.606 * temperature) / 1000; // Cair ≈ (331.3 + 0.606 ⋅ ϑ) m/s
189.         long* times = measureMicroseconds();
190.        
191.         // Calculate the distance in mm for each result.
192.         for (uint8_t i = 0; i < this->echoCount; i++) {
193.                 double distanceMm = times[i] / 2.0 * speedOfSoundInMmPerMs;
194.                 if (distanceMm < 10 || distanceMm > 4000) {
195.                         results[i] = HCSR04_INVALID_RESULT;
196.                 } else {
197.                         results[i] = distanceMm;
198.                 }
199.         }
200. }
202. void HCSR04Sensor::measureDistanceCm(float temperature, double* results) {
203.         if (results == NULL) results = this->lastDistances;
205.         double speedOfSoundInCmPerMs = (331.3 + 0.606 * temperature) / 1000 / 10; // Cair ≈ (331.3 + 0.606 ⋅ ϑ) m/s
206.         long* times = measureMicroseconds();
207.        
208.         // Calculate the distance in cm for each result.
209.         for (uint8_t i = 0; i < this->echoCount; i++) {
210.                 double distanceCm = times[i] / 2.0 * speedOfSoundInCmPerMs;
211.                 if (distanceCm < 1 || distanceCm > 400) {
212.                         results[i] = HCSR04_INVALID_RESULT;
213.                 } else {
214.                         results[i] = distanceCm;
215.                 }
216.         }
217. }
219. void HCSR04Sensor::measureDistanceIn(float temperature, double* results) {
220.         if (results == NULL) results = this->lastDistances;
222.         double speedOfSoundInCmPerMs = (331.3 + 0.606 * temperature) * 39.37007874 / 1000 / 1000; // Cair ≈ (331.3 + 0.606 ⋅ ϑ) m/s
223.         long* times = measureMicroseconds();
225.         // Calculate the distance in cm for each result.
226.         for (uint8_t i = 0; i < this->echoCount; i++) {
227.                 double distanceIn = times[i] / 2.0 * speedOfSoundInCmPerMs;
228.                 if (distanceIn < 1 || distanceIn > 157.4804) {
229.                         results[i] = HCSR04_INVALID_RESULT;
230.                 }
231.                 else {
232.                         results[i] = distanceIn;
233.                 }
234.         }
235. }
237. void HCSR04Sensor::unlockSensors(eUltraSonicUnlock_t unlock, uint8_t* echoPins) {
238.         if (unlock == eUltraSonicUnlock_t::unlockSkip) return;
239.         bool hasLocked = false;
241.         // Check if any sensor is in a locked state and unlock it if necessary.
242.         for (uint8_t i = 0; echoPins[i] != 0; i++) {
243.                 if (unlock == eUltraSonicUnlock_t::unlockMaybe && digitalRead(echoPins[i]) == LOW) continue;
244.                 pinMode(echoPins[i], OUTPUT);
245.                 digitalWrite(echoPins[i], LOW);
246.                 hasLocked = true;
247.         }
248.        
249.         if (hasLocked) delay(100);
251.         // Revert the pinMode after potential unlocking.
252.         for (uint8_t i = 0; echoPins[i] != 0; i++) {
253.                 pinMode(echoPins[i], INPUT);
254.         }
255.        
256.         if (hasLocked) delay(100);
257. }
259. void HCSR04Sensor::triggerInterrupt(uint8_t index) {
260.         if (this->triggerTimes[index] == 0) this->triggerTimes[index] = micros();
261. }
263. void HCSR04Sensor::echoInterrupt(uint8_t index) {
264.         if (this->triggerTimes[index] > 0 && this->echoTimes[index] == 0) this->echoTimes[index] = micros();
265. }
267. void HCSR04Sensor::triggerInterrupt0() { HCSR04.triggerInterrupt(0); }
268. void HCSR04Sensor::triggerInterrupt1() { HCSR04.triggerInterrupt(1); }
269. void HCSR04Sensor::triggerInterrupt2() { HCSR04.triggerInterrupt(2); }
270. void HCSR04Sensor::triggerInterrupt3() { HCSR04.triggerInterrupt(3); }
271. void HCSR04Sensor::triggerInterrupt4() { HCSR04.triggerInterrupt(4); }
272. void HCSR04Sensor::triggerInterrupt5() { HCSR04.triggerInterrupt(5); }
273. void HCSR04Sensor::triggerInterrupt6() { HCSR04.triggerInterrupt(6); }
274. void HCSR04Sensor::triggerInterrupt7() { HCSR04.triggerInterrupt(7); }
275. void HCSR04Sensor::triggerInterrupt8() { HCSR04.triggerInterrupt(8); }
276. void HCSR04Sensor::triggerInterrupt9() { HCSR04.triggerInterrupt(9); }
278. void HCSR04Sensor::echoInterrupt0() { HCSR04.echoInterrupt(0); }
279. void HCSR04Sensor::echoInterrupt1() { HCSR04.echoInterrupt(1); }
280. void HCSR04Sensor::echoInterrupt2() { HCSR04.echoInterrupt(2); }
281. void HCSR04Sensor::echoInterrupt3() { HCSR04.echoInterrupt(3); }
282. void HCSR04Sensor::echoInterrupt4() { HCSR04.echoInterrupt(4); }
283. void HCSR04Sensor::echoInterrupt5() { HCSR04.echoInterrupt(5); }
284. void HCSR04Sensor::echoInterrupt6() { HCSR04.echoInterrupt(6); }
285. void HCSR04Sensor::echoInterrupt7() { HCSR04.echoInterrupt(7); }
286. void HCSR04Sensor::echoInterrupt8() { HCSR04.echoInterrupt(8); }
287. void HCSR04Sensor::echoInterrupt9() { HCSR04.echoInterrupt(9); }
289. HCSR04Sensor HCSR04;

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三、库文件应用举例

下文以超声波传感器的库HCSR04来举行举例（仅分析代码用法，不作实物接线）
在导入HCSR04库之后，可打开库文件中的实例：

1. #include <HCSR04.h>
3. HCSR04 hc(5, 6); //initialisation class HCSR04 (trig pin , echo pin)
4.                  //初始化超声波传感器，即表明接口号。
6. void setup()
7. {
8.     Serial.begin(9600);  //串口初始化
9. }
11. void loop()
12. {
13.     Serial.println(hc.dist()); // return curent distance in serial
14.                                // hc.dist()会返回超声波传感器检测的距离数据
15.     delay(60);                 // 延时60毫秒
16. }

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具体实例可参考文章——Arduino项目式编程讲授第四章——超声波测距
如果想要了解此库文件下的方法，则可以在Arduino软件中，按住【Alt / cmd】键，然后使用鼠标点击对应的库文件名，即可打开其头文件：

在头文件中，可以阅读文件贡献者做出的注释来了解此库文件中可供使用的方法。

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