android开发分享Arduino蓝牙小车制作（Arduino+APP Inventor）

简介：
小车使用Arduino MEGA2560作为主控，4个TT电机带动4WD底盘,4节18650锂电池供电，2个L298N驱动板驱动电机，采用Android APP作为上位机发布指令，操纵小车运动、播放音乐等，两者通过BT蓝牙通信，同时使用2自由度云台辅助超声波传感器探测距离，躲避障碍，灰度传感器进行PID巡线（待完善）、音频解码器和3W喇叭播放音乐、ws2812LED发彩虹光。

使用材料：

MEGA2560开发板、4WD底盘、TT电机X4、L298N驱动板X2、18650锂电池X4、18650电池盒X2、2自由度云台、SG90舵机X2、HC-02蓝牙模块、DFrobot MiNi音频解码器、3W喇叭、ws812全彩LED模块、HCSR04超声波传感器、灰度传感器X2、手机

实物图：

Arduino代码（不含PID巡线）：

 #include<DFRobotDFPlayerMini.h>//DFrobot音频解码器库 #include<Adafruit_NeoPixel.h>//ws2812全彩LED库 #include<Servo.h>//舵机库 //引脚定义 #define led_pin     22 #define LFwheel_1   50 #define LFwheel_2   52 #define LFpwm       11 #define RFwheel_1   46 #define RFwheel_2   48 #define RFpwm       10 #define LBwheel_1   47 #define LBwheel_2   49 #define LBpwm       13 #define RBwheel_1   51 #define RBwheel_2   53 #define RBpwm       12 #define servopin_1  8 #define servopin_2  9 #define Trig_pin    31 #define Echo_pin    33 //计时变量 unsigned long cur_time=0; //对象实例化 DFRobotDFPlayerMini myDFPlayer; Adafruit_NeoPixel strip = Adafruit_NeoPixel(7, led_pin, NEO_GRB + NEO_KHZ800); Servo myservo1; Servo myservo2; void setup() {   //串口波特率设置   Serial2.begin(9600);   Serial3.begin(9600);   Serial.begin(115200);   //调用初始化函数   Init(); }  void loop() {   //读取字符串   String str="";   while(Serial3.available()){     char ch=(char)Serial3.read();     str+=ch;     delay(2);   }      if(str.length()>0){       Serial.println(str);       if(getKey(str)=="up"){           Forward(map(getValue(str),0,70,0,255));//调用前进函数           Serial.print("Forward:");           Serial.println(str);      }          if(getKey(str)=="down"){          Back_off(map(getValue(str),0,70,0,255));//调用后退函数          Serial.print("Back_off:");          Serial.println(str);      }          if(getKey(str)=="left"){          Turn_left(map(getValue(str),0,70,0,150));//调用左转函数          Serial.print("Turn_left:");          Serial.println(str);      }          if(getKey(str)=="right"){         Turn_right(map(getValue(str),0,70,0,150));//调用右转函数         Serial.print("Turn_right:");         Serial.println(str);      }       if(getKey(str)=="stop"){         Stop();//调用停止函数         Serial.print("Stop:");         Serial.println(str);      }      if(getKey(str)=="music"){        myDFPlayer.play(random(1,10));//调用音乐播放函数，在音乐编号1~10中随机播放        Serial.println("Music play");        }      if(getKey(str)=="mustop"){        myDFPlayer.pause();//调用音乐暂停函数        Serial.println("Music sleep");      }      if(getKey(str)=="next"){        myDFPlayer.next();//调用下一曲函数        Serial.println("Next song");      }      if(getKey(str)=="previous"){        myDFPlayer.previous();//调用上一曲函数        Serial.println("Previous song");      }      if(getKey(str)=="light"){        rainbowCycle(10);//调用彩虹闪烁函数        Serial.println("LED rainbow");      }      if(getKey(str)=="dark"){        colorWipe(strip.Color(0, 0, 0), 50);//关灯        Serial.println("LED dark");      }      if(getKey(str)=="vangle"){         myservo2.write(getValue(str));//舵机2垂直转动         //delay(10);         Serial.print("Vertical Angle:");         Serial.println(getValue(str));      }      if(getKey(str)=="hangle"){         myservo1.write(getValue(str));//舵机1水平转动         //delay(10);         Serial.print("Horizon Angle:");         Serial.println(getValue(str));      }     }    if(millis()-cur_time>3000){     cur_time=millis();     if(getDistance()<30){//超声波测距离，如果距离小于30厘米则亮红灯警示       colorWipe(strip.Color(255, 0, 0), 50);       Serial.println("RED LIGHT WARING");     }     else{       colorWipe(strip.Color(0, 0, 0), 50);//否则关灯       Serial.println("BE SAFE");     }        }  }  //定义初始化函数 void Init(){   for(int i=46;i<=53;i++){     pinMode(i,OUTPUT);     digitalWrite(i,LOW);   }   if (!myDFPlayer.begin(Serial2)) {      Serial.println(F("Unable to begin:"));     Serial.println(F("1.Please recheck the connection!"));     Serial.println(F("2.Please insert the SD card!"));     //while(1);      }   myDFPlayer.volume(20);   strip.begin();   strip.show();    myservo1.attach(servopin_1);   myservo2.attach(servopin_2);   pinMode(Trig_pin, OUTPUT);    pinMode(Echo_pin, INPUT);  } //定义前进函数 void Forward(int v){   //左前轮   analogWrite(LFpwm,v);   digitalWrite(LFwheel_1,HIGH);   digitalWrite(LFwheel_2,LOW);      //右前轮   analogWrite(RFpwm,v);   digitalWrite(RFwheel_1,HIGH);   digitalWrite(RFwheel_2,LOW);    //左后轮   analogWrite(LBpwm,v);   digitalWrite(LBwheel_1,LOW);   digitalWrite(LBwheel_2,HIGH);      //右后轮   analogWrite(RBpwm,v);   digitalWrite(RBwheel_1,LOW);   digitalWrite(RBwheel_2,HIGH);    } //定义后退函数 void Back_off(int v){   //左前轮   analogWrite(LFpwm,v);   digitalWrite(LFwheel_1,LOW);   digitalWrite(LFwheel_2,HIGH);      //右前轮   analogWrite(RFpwm,v);   digitalWrite(RFwheel_1,LOW);   digitalWrite(RFwheel_2,HIGH);    //左后轮   analogWrite(LBpwm,v);   digitalWrite(LBwheel_1,HIGH);   digitalWrite(LBwheel_2,LOW);      //右后轮   analogWrite(RBpwm,v);   digitalWrite(RBwheel_1,HIGH);   digitalWrite(RBwheel_2,LOW);    } //定义左转函数 void Turn_left(int v){   //左前轮   analogWrite(LFpwm,v);   digitalWrite(LFwheel_1,LOW);   digitalWrite(LFwheel_2,HIGH);      //右前轮   analogWrite(RFpwm,v);   digitalWrite(RFwheel_1,HIGH);   digitalWrite(RFwheel_2,LOW);    //左后轮   analogWrite(LBpwm,v);   digitalWrite(LBwheel_1,HIGH);   digitalWrite(LBwheel_2,LOW);      //右后轮   analogWrite(RBpwm,v);   digitalWrite(RBwheel_1,LOW);   digitalWrite(RBwheel_2,HIGH); } //定义右转函数 void Turn_right(int v){   //左前轮   analogWrite(LFpwm,v);   digitalWrite(LFwheel_1,HIGH);   digitalWrite(LFwheel_2,LOW);      //右前轮   analogWrite(RFpwm,v);   digitalWrite(RFwheel_1,LOW);   digitalWrite(RFwheel_2,HIGH);    //左后轮   analogWrite(LBpwm,v);   digitalWrite(LBwheel_1,LOW);   digitalWrite(LBwheel_2,HIGH);      //右后轮   analogWrite(RBpwm,v);   digitalWrite(RBwheel_1,HIGH);   digitalWrite(RBwheel_2,LOW); } //定义停止函数 void Stop(){   for(int i=46;i<=53;i++){     digitalWrite(i,LOW);   } } //定义获取标识符函数 String getKey(String str){   int pos0,pos1;   String key;   for(int i=0;i<str.length();i++){     if(str[i]=='!')       pos0=i;     if(str[i]=='@'){       pos1=i;       break;     }          }  key=str.substring(pos0+1,pos1);   return key; } //定义获取数值函数 int getValue(String str){   int pos0,pos1;   int value;   for(int i=0;i<str.length();i++){     if(str[i]=='@')       pos0=i;     if(str[i]=='*'){       pos1=i;       break;     }         }   value=getInt(str.substring(pos0+1,pos1));   return value; } int getInt(String str){   int num=0;   for(int i=0;i<str.length();i++){     num*=10;     num+=str[i]-'0';       }     return num; } //定义LED彩虹闪烁函数 void rainbowCycle(int wait) {   int i, j;    for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel     for(i=0; i< strip.numPixels(); i++) {       strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));     }     strip.show();     delay(wait);   } }  int Wheel(byte WheelPos) {   if(WheelPos < 85) {    return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);   } else if(WheelPos < 170) {    WheelPos -= 85;    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);   } else {    WheelPos -= 170;    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);   } } //定义LED发光函数 void colorWipe(int c, int wait) {   for(int i=0; i<strip.numPixels(); i++) {       strip.setPixelColor(i, c);       strip.show();       delay(wait);   } } //定义超声波获取距离函数 double getDistance(){   double cm;   digitalWrite(Trig_pin, LOW);    delayMicroseconds(2);    digitalWrite(Trig_pin, HIGH);    delayMicroseconds(10);    digitalWrite(Trig_pin, LOW);     cm = pulseIn(Echo_pin, HIGH)/58.0;    cm = (int(cm * 100.0))/100.0;       return cm; } 

APP Inventor GUI 设计：

APP Inventor 代码块（部分）：

结束语：
灰度传感器买错了，所以巡线的部分还没有写。