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:
- /*
- HCSR04 - Library for arduino, for HC-SR04 ultrasonic distance sensor.
- Created by Dirk Sarodnick, 2020.
- */
- #ifndef HCSR04_H
- #define HCSR04_H
- #include "Arduino.h"
- #define HCSR04_INVALID_RESULT -1;
- #define HCSR04_NO_TRIGGER -2;
- #define HCSR04_NO_ECHO -3;
- class HCSR04Sensor {
- public:
- HCSR04Sensor();
- ~HCSR04Sensor();
- typedef enum eUltraSonicUnlock {
- unlockSkip = 0,
- unlockMaybe = 1,
- unlockForced = 2
- } eUltraSonicUnlock_t;
-
- void begin(uint8_t triggerPin, uint8_t echoPin) { begin(triggerPin, new uint8_t[1]{ echoPin }, 1); }
- void begin(uint8_t triggerPin, uint8_t* echoPins, uint8_t echoCount) { begin(triggerPin, echoPins, echoCount, 100000, eUltraSonicUnlock_t::unlockSkip); }
- void begin(uint8_t triggerPin, uint8_t echoPin, uint32_t timeout, eUltraSonicUnlock_t unlock) { begin(triggerPin, new uint8_t[1]{ echoPin }, 1, timeout, unlock); }
- 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); }
- void begin(uint8_t triggerPin, uint8_t* echoPins, uint8_t echoCount, uint32_t timeout, uint16_t triggerTime, uint16_t triggerWait, eUltraSonicUnlock_t unlock);
- void end();
-
- long* measureMicroseconds() { measureMicroseconds(lastMicroseconds); return lastMicroseconds; }
- void measureMicroseconds(long* results);
- double* measureDistanceMm() { measureDistanceMm(defaultTemperature, lastDistances); return lastDistances; }
- void measureDistanceMm(double* results) { measureDistanceMm(defaultTemperature, results == NULL ? lastDistances : results); }
- double* measureDistanceMm(float temperature) { measureDistanceMm(temperature, lastDistances); return lastDistances; }
- void measureDistanceMm(float temperature, double* results);
- double* measureDistanceCm() { measureDistanceCm(defaultTemperature, lastDistances); return lastDistances; }
- void measureDistanceCm(double* results) { measureDistanceCm(defaultTemperature, results == NULL ? lastDistances : results); }
- double* measureDistanceCm(float temperature) { measureDistanceCm(temperature, lastDistances); return lastDistances; }
- void measureDistanceCm(float temperature, double* results);
- double* measureDistanceIn() { measureDistanceIn(defaultTemperature, lastDistances); return lastDistances; }
- void measureDistanceIn(double* results) { measureDistanceIn(defaultTemperature, results == NULL ? lastDistances : results); }
- double* measureDistanceIn(float temperature) { measureDistanceIn(temperature, lastDistances); return lastDistances; }
- void measureDistanceIn(float temperature, double* results);
-
- static void triggerInterrupt0(void);
- static void triggerInterrupt1(void);
- static void triggerInterrupt2(void);
- static void triggerInterrupt3(void);
- static void triggerInterrupt4(void);
- static void triggerInterrupt5(void);
- static void triggerInterrupt6(void);
- static void triggerInterrupt7(void);
- static void triggerInterrupt8(void);
- static void triggerInterrupt9(void);
-
- static void echoInterrupt0(void);
- static void echoInterrupt1(void);
- static void echoInterrupt2(void);
- static void echoInterrupt3(void);
- static void echoInterrupt4(void);
- static void echoInterrupt5(void);
- static void echoInterrupt6(void);
- static void echoInterrupt7(void);
- static void echoInterrupt8(void);
- static void echoInterrupt9(void);
-
- private:
- float defaultTemperature = 19.307;
- long* lastMicroseconds;
- double* lastDistances;
- uint32_t timeout;
- uint16_t triggerTime = 10; // HC-SR04 needs at least 10�s trigger. Others may need longer trigger pulses.
- 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.
- volatile uint8_t triggerPin;
- volatile unsigned long* volatile triggerTimes;
-
- uint8_t echoCount;
- volatile int16_t* volatile echoStages;
- volatile int16_t* volatile echoInts;
- volatile int16_t* volatile echoPorts;
- volatile unsigned long* volatile echoTimes;
-
- void triggerInterrupt(uint8_t);
- void echoInterrupt(uint8_t);
- void unlockSensors(eUltraSonicUnlock_t, uint8_t*);
- };
- extern HCSR04Sensor HCSR04;
- #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:
- /*
- HCSR04 - Library for arduino, for HC-SR04 ultrasonic distance sensor.
- Created by Dirk Sarodnick, 2020.
- */
- #include "Arduino.h"
- #include "HCSR04.h"
- HCSR04Sensor::HCSR04Sensor() {}
- HCSR04Sensor::~HCSR04Sensor() { this->end(); }
- void HCSR04Sensor::begin(uint8_t triggerPin, uint8_t* echoPins, uint8_t echoCount, uint32_t timeout, uint16_t triggerTime, uint16_t triggerWait, eUltraSonicUnlock_t unlock) {
- if (this->echoCount != echoCount) this->end();
-
- this->triggerPin = triggerPin;
- pinMode(triggerPin, OUTPUT);
- this->timeout = timeout;
- this->triggerTime = triggerTime;
- this->triggerWait = triggerWait;
- this->echoCount = echoCount;
-
- if (this->lastMicroseconds == NULL) this->lastMicroseconds = new long[echoCount];
- if (this->lastDistances == NULL) this->lastDistances = new double[echoCount];
-
- if (this->triggerTimes == NULL) this->triggerTimes = new unsigned long[echoCount];
- if (this->echoTimes == NULL) this->echoTimes = new unsigned long[echoCount];
- if (this->echoStages == NULL) this->echoStages = new int16_t[echoCount];
- if (this->echoInts == NULL) this->echoInts = new int16_t[echoCount];
- if (this->echoPorts == NULL) this->echoPorts = new int16_t[echoCount];
- for (uint8_t i = 0; i < this->echoCount; i++) {
- this->triggerTimes[i] = 0;
- this->echoTimes[i] = 0;
- int16_t interrupt = digitalPinToInterrupt(echoPins[i]);
- if (interrupt == NOT_AN_INTERRUPT) {
- this->echoStages[i] = -1;
- this->echoInts[i] = -1;
- this->echoPorts[i] = echoPins[i];
- } else {
- this->echoStages[i] = 0;
- this->echoInts[i] = interrupt;
- this->echoPorts[i] = -1;
- }
- pinMode(echoPins[i], INPUT);
- }
-
- // Unlock sensors that are possibly in a locked state, if this feature is enabled.
- this->unlockSensors(unlock, echoPins);
- }
- void HCSR04Sensor::end() {
- if (this->lastMicroseconds != NULL) delete []this->lastMicroseconds;
- if (this->lastDistances != NULL) delete []this->lastDistances;
- if (this->triggerTimes != NULL) delete []this->triggerTimes;
- if (this->echoTimes != NULL) delete []this->echoTimes;
-
- if (this->echoPorts != NULL) delete []this->echoPorts;
- if (this->echoInts != NULL) delete []this->echoInts;
- if (this->echoStages != NULL) delete []this->echoStages;
-
- this->lastMicroseconds = NULL;
- this->lastDistances = NULL;
- this->triggerTimes = NULL;
- this->echoTimes = NULL;
- this->echoPorts = NULL;
- this->echoInts = NULL;
- this->echoStages = NULL;
- }
- void HCSR04Sensor::measureMicroseconds(long* results) {
- if (results == NULL) results = this->lastMicroseconds;
- bool finished = true;
- bool waiting = true;
- unsigned long startMicros = micros();
- unsigned long currentMicros = 0;
- unsigned long elapsedMicros = 0;
- // Make sure that trigger pin is LOW.
- digitalWrite(triggerPin, LOW);
- delayMicroseconds(4);
-
- // Hold trigger HIGH for 10 microseconds (default), which signals the sensor to measure distance.
- digitalWrite(triggerPin, HIGH);
- delayMicroseconds(this->triggerTime);
- // Set trigger LOW again and wait to give the sensor time for sending the signal without interference
- digitalWrite(triggerPin, LOW);
- delayMicroseconds(this->triggerWait);
-
- // Attach interrupts to echo pins for the starting point
- for (uint8_t i = 0; i < this->echoCount; i++) {
- if (this->echoInts[i] >= 0 && this->echoStages[i] == 0) {
- this->echoStages[i] = 1;
- switch (i) {
- case 0: attachInterrupt(this->echoInts[i], &triggerInterrupt0, RISING); break;
- case 1: attachInterrupt(this->echoInts[i], &triggerInterrupt1, RISING); break;
- case 2: attachInterrupt(this->echoInts[i], &triggerInterrupt2, RISING); break;
- case 3: attachInterrupt(this->echoInts[i], &triggerInterrupt3, RISING); break;
- case 4: attachInterrupt(this->echoInts[i], &triggerInterrupt4, RISING); break;
- case 5: attachInterrupt(this->echoInts[i], &triggerInterrupt5, RISING); break;
- case 6: attachInterrupt(this->echoInts[i], &triggerInterrupt6, RISING); break;
- case 7: attachInterrupt(this->echoInts[i], &triggerInterrupt7, RISING); break;
- case 8: attachInterrupt(this->echoInts[i], &triggerInterrupt8, RISING); break;
- case 9: attachInterrupt(this->echoInts[i], &triggerInterrupt9, RISING); break;
- }
- }
- }
-
- // Wait until all echos are returned or timed out.
- while(true) {
- delayMicroseconds(1);
-
- finished = true;
- waiting = true;
- currentMicros = micros();
- elapsedMicros = currentMicros - startMicros;
- for (uint8_t i = 0; i < this->echoCount; i++) {
- waiting &= elapsedMicros < this->timeout || (this->triggerTimes[i] > 0 && this->echoTimes[i] == 0 && (currentMicros - this->triggerTimes[i]) < this->timeout);
- if (this->echoPorts[i] >= 0 && this->triggerTimes[i] == 0) {
- if (digitalRead(this->echoPorts[i]) == HIGH) this->triggerTimes[i] = micros();
- }
- if (this->triggerTimes[i] > 0 || !waiting) {
- if (this->echoInts[i] >= 0 && (this->echoStages[i] == 1 || !waiting)) {
- if (this->echoStages[i] == 1) this->echoStages[i] = 2;
- detachInterrupt(this->echoInts[i]);
- }
- } else finished &= false;
- if (this->echoInts[i] >= 0 && this->triggerTimes[i] > 0 && this->echoStages[i] == 2 && waiting) {
- this->echoStages[i] = 3;
- switch (i) {
- case 0: attachInterrupt(this->echoInts[i], &echoInterrupt0, FALLING); break;
- case 1: attachInterrupt(this->echoInts[i], &echoInterrupt1, FALLING); break;
- case 2: attachInterrupt(this->echoInts[i], &echoInterrupt2, FALLING); break;
- case 3: attachInterrupt(this->echoInts[i], &echoInterrupt3, FALLING); break;
- case 4: attachInterrupt(this->echoInts[i], &echoInterrupt4, FALLING); break;
- case 5: attachInterrupt(this->echoInts[i], &echoInterrupt5, FALLING); break;
- case 6: attachInterrupt(this->echoInts[i], &echoInterrupt6, FALLING); break;
- case 7: attachInterrupt(this->echoInts[i], &echoInterrupt7, FALLING); break;
- case 8: attachInterrupt(this->echoInts[i], &echoInterrupt8, FALLING); break;
- case 9: attachInterrupt(this->echoInts[i], &echoInterrupt9, FALLING); break;
- }
- }
- if (this->echoPorts[i] >= 0 && this->triggerTimes[i] > 0 && this->echoTimes[i] == 0) {
- if (digitalRead(this->echoPorts[i]) == LOW) this->echoTimes[i] = micros();
- }
-
- if ((this->triggerTimes[i] > 0 && this->echoTimes[i] > 0) || !waiting) {
- if (this->echoInts[i] >= 0 && (this->echoStages[i] == 3 || !waiting)) {
- if (this->echoStages[i] == 3) this->echoStages[i] = 4;
- detachInterrupt(this->echoInts[i]);
- }
- } else finished &= false;
- }
-
- if (!waiting || finished) break;
- }
-
- // Determine the durations of each sensor.
- for (uint8_t i = 0; i < this->echoCount; i++) {
- if (this->echoInts[i] >= 0) this->echoStages[i] = 0;
- if (this->triggerTimes[i] > 0 && this->echoTimes[i] > 0) {
- long resultTime = this->echoTimes[i] - this->triggerTimes[i];
- results[i] = resultTime > 0 ? resultTime : HCSR04_INVALID_RESULT;
- } else if (this->triggerTimes[i] > 0) {
- results[i] = HCSR04_NO_ECHO;
- } else {
- results[i] = HCSR04_NO_TRIGGER;
- }
- this->triggerTimes[i] = 0;
- this->echoTimes[i] = 0;
- }
- }
- void HCSR04Sensor::measureDistanceMm(float temperature, double* results) {
- if (results == NULL) results = this->lastDistances;
- double speedOfSoundInMmPerMs = (331.3 + 0.606 * temperature) / 1000; // Cair ≈ (331.3 + 0.606 ⋅ ϑ) m/s
- long* times = measureMicroseconds();
-
- // Calculate the distance in mm for each result.
- for (uint8_t i = 0; i < this->echoCount; i++) {
- double distanceMm = times[i] / 2.0 * speedOfSoundInMmPerMs;
- if (distanceMm < 10 || distanceMm > 4000) {
- results[i] = HCSR04_INVALID_RESULT;
- } else {
- results[i] = distanceMm;
- }
- }
- }
- void HCSR04Sensor::measureDistanceCm(float temperature, double* results) {
- if (results == NULL) results = this->lastDistances;
- double speedOfSoundInCmPerMs = (331.3 + 0.606 * temperature) / 1000 / 10; // Cair ≈ (331.3 + 0.606 ⋅ ϑ) m/s
- long* times = measureMicroseconds();
-
- // Calculate the distance in cm for each result.
- for (uint8_t i = 0; i < this->echoCount; i++) {
- double distanceCm = times[i] / 2.0 * speedOfSoundInCmPerMs;
- if (distanceCm < 1 || distanceCm > 400) {
- results[i] = HCSR04_INVALID_RESULT;
- } else {
- results[i] = distanceCm;
- }
- }
- }
- void HCSR04Sensor::measureDistanceIn(float temperature, double* results) {
- if (results == NULL) results = this->lastDistances;
- double speedOfSoundInCmPerMs = (331.3 + 0.606 * temperature) * 39.37007874 / 1000 / 1000; // Cair ≈ (331.3 + 0.606 ⋅ ϑ) m/s
- long* times = measureMicroseconds();
- // Calculate the distance in cm for each result.
- for (uint8_t i = 0; i < this->echoCount; i++) {
- double distanceIn = times[i] / 2.0 * speedOfSoundInCmPerMs;
- if (distanceIn < 1 || distanceIn > 157.4804) {
- results[i] = HCSR04_INVALID_RESULT;
- }
- else {
- results[i] = distanceIn;
- }
- }
- }
- void HCSR04Sensor::unlockSensors(eUltraSonicUnlock_t unlock, uint8_t* echoPins) {
- if (unlock == eUltraSonicUnlock_t::unlockSkip) return;
- bool hasLocked = false;
- // Check if any sensor is in a locked state and unlock it if necessary.
- for (uint8_t i = 0; echoPins[i] != 0; i++) {
- if (unlock == eUltraSonicUnlock_t::unlockMaybe && digitalRead(echoPins[i]) == LOW) continue;
- pinMode(echoPins[i], OUTPUT);
- digitalWrite(echoPins[i], LOW);
- hasLocked = true;
- }
-
- if (hasLocked) delay(100);
- // Revert the pinMode after potential unlocking.
- for (uint8_t i = 0; echoPins[i] != 0; i++) {
- pinMode(echoPins[i], INPUT);
- }
-
- if (hasLocked) delay(100);
- }
- void HCSR04Sensor::triggerInterrupt(uint8_t index) {
- if (this->triggerTimes[index] == 0) this->triggerTimes[index] = micros();
- }
- void HCSR04Sensor::echoInterrupt(uint8_t index) {
- if (this->triggerTimes[index] > 0 && this->echoTimes[index] == 0) this->echoTimes[index] = micros();
- }
- void HCSR04Sensor::triggerInterrupt0() { HCSR04.triggerInterrupt(0); }
- void HCSR04Sensor::triggerInterrupt1() { HCSR04.triggerInterrupt(1); }
- void HCSR04Sensor::triggerInterrupt2() { HCSR04.triggerInterrupt(2); }
- void HCSR04Sensor::triggerInterrupt3() { HCSR04.triggerInterrupt(3); }
- void HCSR04Sensor::triggerInterrupt4() { HCSR04.triggerInterrupt(4); }
- void HCSR04Sensor::triggerInterrupt5() { HCSR04.triggerInterrupt(5); }
- void HCSR04Sensor::triggerInterrupt6() { HCSR04.triggerInterrupt(6); }
- void HCSR04Sensor::triggerInterrupt7() { HCSR04.triggerInterrupt(7); }
- void HCSR04Sensor::triggerInterrupt8() { HCSR04.triggerInterrupt(8); }
- void HCSR04Sensor::triggerInterrupt9() { HCSR04.triggerInterrupt(9); }
- void HCSR04Sensor::echoInterrupt0() { HCSR04.echoInterrupt(0); }
- void HCSR04Sensor::echoInterrupt1() { HCSR04.echoInterrupt(1); }
- void HCSR04Sensor::echoInterrupt2() { HCSR04.echoInterrupt(2); }
- void HCSR04Sensor::echoInterrupt3() { HCSR04.echoInterrupt(3); }
- void HCSR04Sensor::echoInterrupt4() { HCSR04.echoInterrupt(4); }
- void HCSR04Sensor::echoInterrupt5() { HCSR04.echoInterrupt(5); }
- void HCSR04Sensor::echoInterrupt6() { HCSR04.echoInterrupt(6); }
- void HCSR04Sensor::echoInterrupt7() { HCSR04.echoInterrupt(7); }
- void HCSR04Sensor::echoInterrupt8() { HCSR04.echoInterrupt(8); }
- void HCSR04Sensor::echoInterrupt9() { HCSR04.echoInterrupt(9); }
- HCSR04Sensor HCSR04;
复制代码 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:
- #include <HCSR04.h>
- HCSR04 hc(5, 6); //initialisation class HCSR04 (trig pin , echo pin)
- //初始化超声波传感器,即表明接口号。
- void setup()
- {
- Serial.begin(9600); //串口初始化
- }
- void loop()
- {
- Serial.println(hc.dist()); // return curent distance in serial
- // hc.dist()会返回超声波传感器检测的距离数据
- delay(60); // 延时60毫秒
- }
复制代码 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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