Node.js连接4个Arduino串口异常：仅一个可接收数据其余无响应

Hey there! Let's figure out why only one of your Arduino devices is sending data when connected together. Looking at your code, the issue is pretty clear: you're only listening for data events on the first serial port, and your listener setup is tied to individual client connections in a way that breaks things for multiple devices.

What's Wrong With Your Current Code? #

1. Redundant SerialPort Requires: You don't need to require('serialport') four times—once is enough, and you can create multiple instances from that single import.
2. Missing Listeners for Other Ports: You've initialized serial1, serial2, and serial3, but you never added a data event listener to any of them. That's why only the first port (serial) is sending data to your frontend.
3. Client-Tied Listener Logic: You're binding the serial data listener every time a client connects, and removing it when a client disconnects. If multiple clients connect, you'll end up with duplicate listeners, and disconnecting one client will stop data from that port for everyone else.

Fixed Code Examples #

1. Optimized Serial Port Initialization

First, clean up your port setup—no need for repeated imports:

// Load all required modules once
const http = require('http');
const fs = require('fs');
const path = require('path');
const SerialPort = require('serialport'); // Single import is enough

// Initialize all four serial ports in an array for easier management
const serialPorts = [
  new SerialPort('/dev/cu.usbserial-1411140', { baudRate: 115200 }, () => console.log('1411140 ready')),
  new SerialPort('/dev/cu.usbserial-141120', { baudRate: 115200 }, () => console.log('141120 ready')),
  new SerialPort('/dev/cu.usbmodem-1411301', { baudRate: 115200 }, () => console.log('1411301 ready')),
  new SerialPort('/dev/cu.usbserial-1411130', { baudRate: 115200 }, () => console.log('1411130 ready'))
];

const port = 8080;

2. Updated Socket.IO & Data Forwarding Logic

We'll decouple the serial port listeners from client connections, and add listeners for all ports:

const io = require('socket.io')(server);

// Reusable message forwarding function (works for all ports)
function forwardMessage(data) {
  let message = data.toString().replace(/\n*/, '');
  
  // Forward messages to frontend just like you did before
  if (message.includes('Coinv')) {
    io.emit('CoinvChange', message.substring(7)); // Use io.emit to send to all connected clients
  }
  if (message.includes('Impor')) {
    io.emit('ImporChange', message.substring(7));
  }
  if (message.includes('Piace')) {
    io.emit('PiaceChange', message.substring(7));
  }
  if (message.includes('Cresc')) {
    io.emit('CrescChange', message.substring(7));
  }
  if (message.includes('Press')) {
    io.emit('PressChange', message.substring(7));
  }
}

// Attach the listener to EVERY serial port when the server starts
serialPorts.forEach(port => {
  port.on('data', forwardMessage);
});

io.on('connection', (socket) => {
  console.log('a new client connected');
  socket.emit('greetings', 'You are now connected to the server through Socket IO');

  socket.on('disconnect', () => {
    console.log('client disconnected');
    // No need to remove serial listeners here—they're global and persist for all clients
  });
});

Extra Tips (Optional) #

If you need to tell which Arduino device is sending each message, modify your Arduino code to add a unique prefix to every message (e.g., Device1:Coinv:5). Then update the forwardMessage function to parse that prefix and include it in the Socket.IO emit—this way your frontend can distinguish between data from different devices.

内容的提问来源于stack exchange，提问作者Lab Sintesi