Arduino 与 Python 之间的通信

Question

我需要用我的笔记本电脑与 Arduino 交谈（发送命令来控制状态机以制作一个简单的自动售货机）当我尝试将命令放入串行监视器时一切看起来都很好但是当我发送命令时通过 python 无效。看起来状态没有像我预期的那样改变。

这里是 python 代码：

def query():
   cmd = "0"
   dev = serial.Serial("COM3", 9600,timeout=5)
   time.sleep(2)
   dev.write(cmd.encode("utf-8"))
   print("Pyhton: Query                  ",dev.readline())
   #time.sleep(1)
   #print(dev.readline())

def up():
   cmd = "1"
   dev = serial.Serial("COM3", 9600)
   time.sleep(2)
   dev.write(cmd.encode("utf-8"))
   print("Pyhton: up                     ",dev.readline())
   #time.sleep(1)
   #print(dev.readline())

def pickup():
   cmd = "2"
   dev = serial.Serial("COM3", 9600)
   time.sleep(2)
   dev.write(cmd.encode("utf-8"))
   print("Pyhton: pickup                  ",dev.readline())
   #time.sleep(1)
   #print(dev.readline())


def ship():
   cmd = "3"
   dev = serial.Serial("COM3", 9600)
   time.sleep(2)
   dev.write(cmd.encode("utf-8"))
   print("Pyhton: ship                 ",dev.readline())
   #time.sleep(1)
   #print(dev.readline())


def origin():
   cmd = "4"
   dev = serial.Serial("COM3", 9600)
   time.sleep(2)
   dev.write(cmd.encode("utf-8"))
   print("Pyhton: origin               ",dev.readline())
   #time.sleep(1)
   #print(dev.readline())


tokenDict = {
   "001":query,
   "002":up,
   "003":ship,
   "004":pickup,
   "005":origin
   }

lineList = [line.rstrip('\n') for line in open("cmd.txt")]

for line in lineList:
   time.sleep(1)
   functionToCall = tokenDict[line]
   functionToCall()

这是 Arduino 代码：

int cmd = 0;
enum {IDLEx, UP, PICKUP, SHIP, ORIGIN};
uint8_t STATE = IDLEx;

void setup() {
  Serial.begin(9600);
  //Serial.flush();
  pinMode(LED_BUILTIN, OUTPUT);
}

void readSerialData() {
  if (Serial.available()>0) {
    delay(300);
    //cmd = Serial.readStringUntil('\n');
    cmd = Serial.read();
    process_serial(cmd, &STATE);
    //test(cmd);
  }
}

  void process_serial(int data, uint8_t *state)
  {
    switch (*state)

    {
      case IDLEx: {
          if (data == '0') {
            *state = IDLEx;
            Serial.println("Arduino: IDLE");

          } else if (data == '1' ) { //go to up state
            *state = UP;
            //Serial.println("Arduino: Up");
          } else if (data == '2') {
            *state = PICKUP;
            //Serial.println("Arduino: PICKUP");
          } else if (data == '3') {
            //Serial.println("Arduino: SHIP");
            *state = SHIP;
          } else if (data == '4') {
            //Serial.println("Arduino: ORIGIN");
            *state = ORIGIN;
          } 
          break;
        }
      case UP: {
          Serial.println("Arduino: UP");
          delay(1000);
          *state = PICKUP;
          break;
        }
      case PICKUP: {
          Serial.println("Arduino: PICKUP");
          delay(1000);
          *state = SHIP;
          break;
        }
      case SHIP: {
          Serial.println("Arduino: SHIP");
          delay(1000);
          *state = ORIGIN;
          break;
        }
      case ORIGIN: {
          Serial.println("Arduino: ORIGIN");
          delay(1000);
          *state = IDLEx;
        }
        break;
    }
  }
  void loop() {
    //Serial.println(STATE);
    readSerialData();
  }

我从文本文件中读取了类似

的命令

这是我期望的输出：

Pyhton: Query                   b'Arduino: IDLE\r\n'
Pyhton: Query                   b'Arduino: IDLE\r\n'
Pyhton: up                      b'Arduino: Up\r\n'
Pyhton: Query                   b'Arduino: Up\r\n'
Pyhton: Query                   b'Arduino: Up\r\n'
Pyhton: ship                  b'Arduino: SHIP\r\n'
Pyhton: Query                   b'Arduino: SHIP\r\n'
Pyhton: pickup                   b'Arduino: PICKUP\r\n'
Pyhton: Query                   b'Arduino: PICKUP\r\n'
Pyhton: origin                b'Arduino: ORIGIN\r\n'

我的问题是当我将数据发送到 Arduino 时，Arduino 似乎没有改变状态（Swith case 作为代码）请注意我使用 Arduino nano 328 和 python 3.x 可以有人建议我吗？我该如何解决这个问题？

Answer 1

在你的每一个函数中你都有这一行：

dev = serial.Serial("COM3", 9600)

该行打开用于重置 Arduino 板的串行端口。为避免这种情况，您应该在程序开始时打开该端口一次，然后每次都继续使用同一个串行端口实例，而不是在每个函数中重新创建它。

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