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、库文件源代码说明
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网站来进行查询下载，然后在Arduino软件中进行导入。
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进行导入库

首先在网页地址框直接输入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：

最后打开Arduino软件，选择【项目】-【导入库】-【添加.ZIP库】然后选择对应的zip文件即可导入成功。

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“书籍”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，当然有些时候要使用的库在软件中查询不到，此时就需要采用第一种方案进行导入。

2、库文件源代码说明

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，用于帮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】文件说明

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.
*/#ifndefHCSR04_H#defineHCSR04_H#include"Arduino.h"#defineHCSR04_INVALID_RESULT-1;#defineHCSR04_NO_TRIGGER-2;#defineHCSR04_NO_ECHO-3;classHCSR04Sensor{public:HCSR04Sensor();~HCSR04Sensor();typedefenumeUltraSonicUnlock{
            unlockSkip =0,
            unlockMaybe =1,
            unlockForced =2} eUltraSonicUnlock_t;voidbegin(uint8_t triggerPin,uint8_t echoPin){begin(triggerPin,newuint8_t[1]{ echoPin },1);}voidbegin(uint8_t triggerPin,uint8_t* echoPins,uint8_t echoCount){begin(triggerPin, echoPins, echoCount,100000, eUltraSonicUnlock_t::unlockSkip);}voidbegin(uint8_t triggerPin,uint8_t echoPin,uint32_t timeout, eUltraSonicUnlock_t unlock){begin(triggerPin,newuint8_t[1]{ echoPin },1, timeout, unlock);}voidbegin(uint8_t triggerPin,uint8_t* echoPins,uint8_t echoCount,uint32_t timeout, eUltraSonicUnlock_t unlock){begin(triggerPin, echoPins, echoCount, timeout,10,10, unlock);}voidbegin(uint8_t triggerPin,uint8_t* echoPins,uint8_t echoCount,uint32_t timeout,uint16_t triggerTime,uint16_t triggerWait, eUltraSonicUnlock_t unlock);voidend();long*measureMicroseconds(){measureMicroseconds(lastMicroseconds);return lastMicroseconds;}voidmeasureMicroseconds(long* results);double*measureDistanceMm(){measureDistanceMm(defaultTemperature, lastDistances);return lastDistances;}voidmeasureDistanceMm(double* results){measureDistanceMm(defaultTemperature, results ==NULL? lastDistances : results);}double*measureDistanceMm(float temperature){measureDistanceMm(temperature, lastDistances);return lastDistances;}voidmeasureDistanceMm(float temperature,double* results);double*measureDistanceCm(){measureDistanceCm(defaultTemperature, lastDistances);return lastDistances;}voidmeasureDistanceCm(double* results){measureDistanceCm(defaultTemperature, results ==NULL? lastDistances : results);}double*measureDistanceCm(float temperature){measureDistanceCm(temperature, lastDistances);return lastDistances;}voidmeasureDistanceCm(float temperature,double* results);double*measureDistanceIn(){measureDistanceIn(defaultTemperature, lastDistances);return lastDistances;}voidmeasureDistanceIn(double* results){measureDistanceIn(defaultTemperature, results ==NULL? lastDistances : results);}double*measureDistanceIn(float temperature){measureDistanceIn(temperature, lastDistances);return lastDistances;}voidmeasureDistanceIn(float temperature,double* results);staticvoidtriggerInterrupt0(void);staticvoidtriggerInterrupt1(void);staticvoidtriggerInterrupt2(void);staticvoidtriggerInterrupt3(void);staticvoidtriggerInterrupt4(void);staticvoidtriggerInterrupt5(void);staticvoidtriggerInterrupt6(void);staticvoidtriggerInterrupt7(void);staticvoidtriggerInterrupt8(void);staticvoidtriggerInterrupt9(void);staticvoidechoInterrupt0(void);staticvoidechoInterrupt1(void);staticvoidechoInterrupt2(void);staticvoidechoInterrupt3(void);staticvoidechoInterrupt4(void);staticvoidechoInterrupt5(void);staticvoidechoInterrupt6(void);staticvoidechoInterrupt7(void);staticvoidechoInterrupt8(void);staticvoidechoInterrupt9(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.volatileuint8_t triggerPin;volatileunsignedlong*volatile triggerTimes;uint8_t echoCount;volatileint16_t*volatile echoStages;volatileint16_t*volatile echoInts;volatileint16_t*volatile echoPorts;volatileunsignedlong*volatile echoTimes;voidtriggerInterrupt(uint8_t);voidechoInterrupt(uint8_t);voidunlockSensors(eUltraSonicUnlock_t,uint8_t*);};extern HCSR04Sensor HCSR04;#endif// HCSR04_H

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();}voidHCSR04Sensor::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 =newlong[echoCount];if(this->lastDistances ==NULL)this->lastDistances =newdouble[echoCount];if(this->triggerTimes ==NULL)this->triggerTimes =newunsignedlong[echoCount];if(this->echoTimes ==NULL)this->echoTimes =newunsignedlong[echoCount];if(this->echoStages ==NULL)this->echoStages =newint16_t[echoCount];if(this->echoInts ==NULL)this->echoInts =newint16_t[echoCount];if(this->echoPorts ==NULL)this->echoPorts =newint16_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);}voidHCSR04Sensor::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;}voidHCSR04Sensor::measureMicroseconds(long* results){if(results ==NULL) results =this->lastMicroseconds;bool finished =true;bool waiting =true;unsignedlong startMicros =micros();unsignedlong currentMicros =0;unsignedlong 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 interferencedigitalWrite(triggerPin, LOW);delayMicroseconds(this->triggerWait);// Attach interrupts to echo pins for the starting pointfor(uint8_t i =0; i <this->echoCount; i++){if(this->echoInts[i]>=0&&this->echoStages[i]==0){this->echoStages[i]=1;switch(i){case0:attachInterrupt(this->echoInts[i],&triggerInterrupt0, RISING);break;case1:attachInterrupt(this->echoInts[i],&triggerInterrupt1, RISING);break;case2:attachInterrupt(this->echoInts[i],&triggerInterrupt2, RISING);break;case3:attachInterrupt(this->echoInts[i],&triggerInterrupt3, RISING);break;case4:attachInterrupt(this->echoInts[i],&triggerInterrupt4, RISING);break;case5:attachInterrupt(this->echoInts[i],&triggerInterrupt5, RISING);break;case6:attachInterrupt(this->echoInts[i],&triggerInterrupt6, RISING);break;case7:attachInterrupt(this->echoInts[i],&triggerInterrupt7, RISING);break;case8:attachInterrupt(this->echoInts[i],&triggerInterrupt8, RISING);break;case9: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){case0:attachInterrupt(this->echoInts[i],&echoInterrupt0, FALLING);break;case1:attachInterrupt(this->echoInts[i],&echoInterrupt1, FALLING);break;case2:attachInterrupt(this->echoInts[i],&echoInterrupt2, FALLING);break;case3:attachInterrupt(this->echoInts[i],&echoInterrupt3, FALLING);break;case4:attachInterrupt(this->echoInts[i],&echoInterrupt4, FALLING);break;case5:attachInterrupt(this->echoInts[i],&echoInterrupt5, FALLING);break;case6:attachInterrupt(this->echoInts[i],&echoInterrupt6, FALLING);break;case7:attachInterrupt(this->echoInts[i],&echoInterrupt7, FALLING);break;case8:attachInterrupt(this->echoInts[i],&echoInterrupt8, FALLING);break;case9: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;}elseif(this->triggerTimes[i]>0){
            results[i]= HCSR04_NO_ECHO;}else{
            results[i]= HCSR04_NO_TRIGGER;}this->triggerTimes[i]=0;this->echoTimes[i]=0;}}voidHCSR04Sensor::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/slong* 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;}}}voidHCSR04Sensor::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/slong* 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;}}}voidHCSR04Sensor::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/slong* 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;}}}voidHCSR04Sensor::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);}voidHCSR04Sensor::triggerInterrupt(uint8_t index){if(this->triggerTimes[index]==0)this->triggerTimes[index]=micros();}voidHCSR04Sensor::echoInterrupt(uint8_t index){if(this->triggerTimes[index]>0&&this->echoTimes[index]==0)this->echoTimes[index]=micros();}voidHCSR04Sensor::triggerInterrupt0(){ HCSR04.triggerInterrupt(0);}voidHCSR04Sensor::triggerInterrupt1(){ HCSR04.triggerInterrupt(1);}voidHCSR04Sensor::triggerInterrupt2(){ HCSR04.triggerInterrupt(2);}voidHCSR04Sensor::triggerInterrupt3(){ HCSR04.triggerInterrupt(3);}voidHCSR04Sensor::triggerInterrupt4(){ HCSR04.triggerInterrupt(4);}voidHCSR04Sensor::triggerInterrupt5(){ HCSR04.triggerInterrupt(5);}voidHCSR04Sensor::triggerInterrupt6(){ HCSR04.triggerInterrupt(6);}voidHCSR04Sensor::triggerInterrupt7(){ HCSR04.triggerInterrupt(7);}voidHCSR04Sensor::triggerInterrupt8(){ HCSR04.triggerInterrupt(8);}voidHCSR04Sensor::triggerInterrupt9(){ HCSR04.triggerInterrupt(9);}voidHCSR04Sensor::echoInterrupt0(){ HCSR04.echoInterrupt(0);}voidHCSR04Sensor::echoInterrupt1(){ HCSR04.echoInterrupt(1);}voidHCSR04Sensor::echoInterrupt2(){ HCSR04.echoInterrupt(2);}voidHCSR04Sensor::echoInterrupt3(){ HCSR04.echoInterrupt(3);}voidHCSR04Sensor::echoInterrupt4(){ HCSR04.echoInterrupt(4);}voidHCSR04Sensor::echoInterrupt5(){ HCSR04.echoInterrupt(5);}voidHCSR04Sensor::echoInterrupt6(){ HCSR04.echoInterrupt(6);}voidHCSR04Sensor::echoInterrupt7(){ HCSR04.echoInterrupt(7);}voidHCSR04Sensor::echoInterrupt8(){ HCSR04.echoInterrupt(8);}voidHCSR04Sensor::echoInterrupt9(){ HCSR04.echoInterrupt(9);}

HCSR04Sensor HCSR04;

三、库文件应用举例

下文以超声波传感器的库HCSR04来进行举例（仅说明代码用法，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。voidsetup(){
    Serial.begin(9600);//串口初始化}voidloop(){
    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}

具体实例可参考文章——Arduino项目式编程教学第四章——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。