Can't communicate with four Arduino's over serial port node.js

Question

I can't communicate to four Arduino's at the same time. I tried the code below with three serial ports and it worked fine. If I add a fourth Arduino, there is no communication with any Arduino.
Can somebody help me?

var SerialPort = require('serialport');
sport1 = new SerialPort('COM10', { autoOpen: true ,
  parser: SerialPort.parsers.readline('\n'), baudRate: 9600});
sport2 = new SerialPort('COM11', { autoOpen: true ,
  parser: SerialPort.parsers.readline('\n'), baudRate: 9600});
sport3 = new SerialPort('COM12', { autoOpen: true ,
  parser: SerialPort.parsers.readline('\n'), baudRate: 9600});
sport4 = new SerialPort('COM13', { autoOpen: true ,
  parser: SerialPort.parsers.readline('\n'), baudRate: 9600});

var u = 0;
  setInterval(function() {
    if(u==0) {
        sport1.write("a");
        sport2.write("b");
        sport3.write("a");
        sport4.write("b");
    }else {
        sport1.write("b");
        sport2.write("a");
        sport3.write("a");
        sport4.write("b");
    }
    u = !u;
  },500);

How the arduinos connected to your computer? do you use USB hub? — idanp

idanp idanp · Accepted Answer · 2017-02-22T06:55:53

Seems like an hardware issue - USB hub tend to cause issues. I suggest the following:

Don't use USB hub (extend USB from PCI)
Use reliable USB hub
Anyway, connect to your USB hub the 5V input it needs.
Extend the serial ports on your computer instead of using many USB to RS232
Maybe connect all your Arduinos to one RS485 bus instead

Can't communicate with four Arduino's over serial port node.js

1 Answers