Python向Arduino 16x2 LCD发送字符串遇串口通信问题求助

Let's tackle this serial communication issue step by step. First, your provided Arduino code cuts off mid-while loop, which is a big part of the problem. Let's fix that and build a robust setup to send strings from Python to your LCD.

Updated Arduino Code #

This version handles serial data reception properly, includes timeout logic, and uses a delimiter to split text across the two LCD lines:

#include <LiquidCrystal.h>
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

// Use a pipe | as a delimiter to separate LCD line 1 and line 2
const char delimiter = '|';
String incomingString = "";
const unsigned long timeout = 10; // 10ms timeout for serial reception

void setup() {
  lcd.begin(16, 2);
  Serial.begin(9600);
  lcd.print("Waiting for data");
}

void loop() {
  incomingString = "";
  unsigned long startTime = millis();

  // Read serial data until timeout or newline (message end)
  while (millis() - startTime < timeout || Serial.available()) {
    if (Serial.available() > 0) {
      char c = Serial.read();
      // Stop reading if we hit a newline (our message terminator)
      if (c == '\n') {
        break;
      }
      incomingString += c;
      startTime = millis(); // Reset timeout when new data arrives
    }
  }

  // If we received a valid string, process it for the LCD
  if (incomingString.length() > 0) {
    int delimiterIndex = incomingString.indexOf(delimiter);
    if (delimiterIndex != -1) {
      // Split the string into two lines
      String line1 = incomingString.substring(0, delimiterIndex);
      String line2 = incomingString.substring(delimiterIndex + 1);

      // Clear LCD and print the lines
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print(line1.substring(0,16)); // Limit to 16 chars for line 1
      lcd.setCursor(0, 1);
      lcd.print(line2.substring(0,16)); // Limit to 16 chars for line 2
    } else {
      // If no delimiter, print everything on line 1
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print(incomingString.substring(0,16));
    }
  }
}

Python Serial Sender Code #

First, install the pyserial library if you haven't already:

pip install pyserial

Then use this script to send text to the Arduino. Replace 'COM3' with your Arduino's serial port (on Linux/macOS this will be /dev/ttyACM0 or similar):

import serial
import time

# Configure serial port
ser = serial.Serial(
    port='COM3',  # Replace with your port
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS,
    timeout=1
)

time.sleep(2)  # Wait for Arduino to initialize

# Send a message: format is "Line1|Line2\n"
message = "Hello from Python|LCD Test!\n"
ser.write(message.encode())

print("Message sent!")
ser.close()

Debugging Tips #

• Check Serial Port: Verify the port in your Python script matches the one in Arduino IDE (Tools > Port).
• Avoid Port Conflicts: Close the Arduino IDE's serial monitor before running the Python script—only one program can access the serial port at a time.
• Test with Serial Monitor: First, send a string like First Line|Second Line\n via the Arduino serial monitor to confirm the LCD works correctly.
• Limit String Length: The 16x2 LCD can only show 16 characters per line, so the code truncates longer strings to prevent overflow.

内容的提问来源于stack exchange，提问作者Enrico Martini