Arduino 蓝牙遥控 + 超声避障小车


在上述代码中，ultrasonicOutputPin 连接超声波模块的 Trig 引脚，ultrasonicInputPin连接超声波模块的 Echo 引脚。

基于超声波模块的工作原理，故超声波测距适用于坚硬平整的较大物体，其他场景性能不佳。

## HC-06（HC-05）蓝牙模块

HC-06 和 HC-05 模块大致差不多，对于 Arduino 的用户，一般从淘宝直接买 JY-MCU，本人也不例外。模块使用起来和串口类似。模块提供的[用户指引（User Guide）](https://core-electronics.com.au/attachments/guides/Product-User-Guide-JY-MCU-Bluetooth-UART-R1-0.pdf "用户指引（User Guide）")中提供了丰富详尽的例子，同样在下面的文章中我也会简单介绍。

考虑到小车的拓展性，例如之后可能会接 ESP8266 啥的，暂时先不占用 Arduino 的硬件串口，留着以后使用，蓝牙模块与板子的连接使用软串口的方式。同样软串口相关的内容会在下面进行阐述。

软串口连接蓝牙模块的参考代码如下：

```cpp
#include <SoftwareSerial.h>

SoftwareSerial bluetoothSerial(11, 12); // RX, TX

void setup() {
  // put your setup code here, to run once:
  Serial.begin(57600);
  bluetoothSerial.begin(57600);
   bluetoothSerial.print("AT");
  delay(1000);
  bluetoothSerial.println("AT+VERSION");
  delay(1000);
  bluetoothSerial.println("AT+BAUD7");
  delay(1000);
  bluetoothSerial.println("AT+NAMEarduino_car");
  delay(1000);
}
void bluetoothTaskCallback() {
  if (bluetoothSerial.available()) {
    int bluetoothCmd = (int)bluetoothSerial.read();
    Serial.print("bluttooth Command: ");
    Serial.println(bluetoothCmd);

    // TODO: 蓝牙传入参数校验
    motorCtrl(bluetoothCmd);
  }
  if (Serial.available()) {
    Serial.print("Serial available: ");
    Serial.println(Serial.read());
    bluetoothSerial.write(Serial.read());
  }
}

#include <TaskScheduler.h>
Scheduler runner;
void ultrasonicTaskCallback();
void bluetoothTaskCallback();
Task bluetoothTask(150,TASKFOREVER,&bluetoothTaskCallback, &runner, true);
Task ultrasonicTask(500,TASKFOREVER,&ultrasonicTaskCallback, &runner,true);
void loop() {
  runner.execute();
}

#include <SoftwareSerial.h>
#include <TaskScheduler.h>
#define STOP 0
#define FORWARD 1
#define BACKWARD 2
#define TURNLEFT 3
#define TURNRIGHT 4
#define CHANGESPEED 5
#define DEFAULTVOLTAGE 150
#define MINVOLTAGE 0
#define MAXVOLTAGE 255
#define LOWSPEED 0
#define HIGHSPEED 1
SoftwareSerial bluetoothSerial(11, 12); // RX, TX
 Scheduler runner;
 void ultrasonicTaskCallback();
 void bluetoothTaskCallback();
Task bluetoothTask(150,TASKFOREVER,&bluetoothTaskCallback, &runner, true);
Task ultrasonicTask(500,TASKFOREVER,&ultrasonicTaskCallback, &runner,true);
// declare motor driver module ctrl pin:
int leftMotorPin1 = 7;
int leftMotorPin2 = 6;
int rightMotorPin1 = 5;
int rightMotorPin2 = 4;
int leftPWM = 10;
int rightPWM = 9;
int ultrasonicInputPin = 2; // Echo
int ultrasonicOutputPin = 3; // Trig
int motorAction = STOP;
int motorVoltage = MINVOLTAGE;
int motorSpeedLevel = HIGHSPEED;
int distance = 0;
/
  motor ctrl matrix
  1. stop
  2. forward
  3. backward
  4. turn left
  5. turn right
/
int ctrlMatrix[5][4] = {
  {LOW, LOW, LOW, LOW},
  {LOW, HIGH, LOW, HIGH},
  {HIGH, LOW, HIGH, LOW},
  {HIGH, LOW, LOW, HIGH},
  {LOW, HIGH, HIGH, LOW}
};
void motorRun(int cmd) {
  Serial.print("recv cmd: ");
  Serial.println(cmd);
  digitalWrite(leftMotorPin1, ctrlMatrix[cmd][0]);
  digitalWrite(leftMotorPin2, ctrlMatrix[cmd][1]);
  digitalWrite(rightMotorPin1, ctrlMatrix[cmd][2]);
  digitalWrite(rightMotorPin2, ctrlMatrix[cmd][3]);
}
void changeSpeed(int voltage) {
  Serial.print("recv voltage: ");
  Serial.println(voltage);
  analogWrite(leftPWM, voltage);
  analogWrite(rightPWM, voltage);
}
void changeSpeedLevel(int level) {
  Serial.print("recv voltage level: ");
  Serial.println(level);
  if (level == HIGHSPEED) {
    analogWrite(leftPWM, MAXVOLTAGE);
    analogWrite(rightPWM, MAXVOLTAGE);
  } else {
    analogWrite(leftPWM, DEFAULTVOLTAGE);
    analogWrite(rightPWM, DEFAULTVOLTAGE);
  }
}
void bluetoothTaskCallback() {
  if (bluetoothSerial.available()) {
    int bluetoothCmd = (int)bluetoothSerial.read();
    Serial.print("bluttooth Command: ");
    Serial.println(bluetoothCmd);
    motorCtrl(bluetoothCmd);
  }
  if (Serial.available()) {
    Serial.print("Serial available: ");
    Serial.println(Serial.read());
    bluetoothSerial.write(Serial.read());
  }
}
void ultrasonicTaskCallback() {
  int distance = getDistance();
  if (distance <= 30) {
    motorRun(STOP);
    Serial.print("distance is dangerous: ");
    Serial.println(distance);
    if (bluetoothSerial.available()) {
      bluetoothSerial.print("distance is dangerous: ");
      bluetoothSerial.println(distance);
    }
    changeSpeedLevel(LOWSPEED);
    motorRun(STOP);
  } else if (distance >= 100) {
    if (bluetoothSerial.available()) {
      bluetoothSerial.print("distance is fine,speed up: ");
      bluetoothSerial.println(distance);
    }
    motorRun(motorAction);
    changeSpeedLevel(HIGHSPEED);
  } else {
    if (bluetoothSerial.available()) {
      bluetoothSerial.print("distance is just ok: ");
      bluetoothSerial.println(distance);
    }
    motorRun(motorAction);
  }
}
void setup()
{
  // put your setup code here, to run once:
  Serial.begin(57600);
  bluetoothSerial.begin(57600);
   bluetoothSerial.print("AT");
  delay(1000);
  bluetoothSerial.println("AT+VERSION");
  delay(1000);
  bluetoothSerial.println("AT+BAUD7");
  delay(1000);
  bluetoothSerial.println("AT+NAMEarduino_car");
  delay(1000);
  // set pin mode for motor
  pinMode(leftMotorPin1, OUTPUT);
  pinMode(leftMotorPin2, OUTPUT);
  pinMode(rightMotorPin1, OUTPUT);
  pinMode(rightMotorPin2, OUTPUT);
  pinMode(leftPWM, OUTPUT);
  pinMode(rightPWM, OUTPUT);
  pinMode(ultrasonicInputPin, INPUT);
  pinMode(ultrasonicOutputPin, OUTPUT);
  changeSpeedLevel(motorSpeedLevel);
  runner.startNow();
  Serial.println("setup has been down.");
}
void motorCtrl(int cmd) {
  if (cmd >= STOP && cmd <= TURNRIGHT) {
    motorAction = cmd;
    motorRun(motorAction);
  } else if (cmd > DEFAULTVOLTAGE && cmd <= MAXVOLTAGE) {
    motorVoltage = cmd;
    changeSpeed(cmd);
  } else if (cmd == CHANGESPEED) {
    if (motorSpeedLevel == LOWSPEED) {
      motorSpeedLevel = HIGHSPEED;
    } else {
      motorSpeedLevel = LOWSPEED;
    }
    changeSpeedLevel(motorSpeedLevel);
  }
}
int getDistance () {
  digitalWrite(ultrasonicOutputPin, LOW);
  delayMicroseconds(2);
  digitalWrite(ultrasonicOutputPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(ultrasonicOutputPin, LOW);
  int distance = pulseIn(ultrasonicInputPin, HIGH);
  distance = distance / 58;
  return distance > 0 ? distance: 0;
}
void loop() {
  runner.execute();
}