Raspberry Pi，Arduino，Node.js和串口

Posted 2021-04-16

我试图从node.js服务器脚本与我的arduino交谈。

这是我的代码：

var app = require('express')()
, server = require('http').createServer(app)
, io = require('socket.io').listen(server)
, SerialPort  = require('serialport').SerialPort;

//SERIAL
var portName = '/dev/ttyACM0';
var sp = new SerialPort(); // instantiate the serial port.
sp.open(portName, { // portName is instatiated to be COM3, replace as necessary
   baudRate: 115200, // this is synced to what was set for the Arduino Code
   dataBits: 8, // this is the default for Arduino serial communication
   parity: 'none', // this is the default for Arduino serial communication
   stopBits: 1, // this is the default for Arduino serial communication
   flowControl: false // this is the default for Arduino serial communication
});

//SERVER
server.listen(80, '127.0.0.5');

app.get('/', function (req, res){
  res.sendfile(__dirname + '/index.html');
});

io.sockets.on('connection', function (socket){
  socket.emit('test', { test: 'Its Working' });
  socket.on('value', function (data){
    console.log(data);
    });
});

我很确定我的设备在/ dev / ttyACM0上，因为：

pi@raspberrypi ~/Programming/node $ dmesg|tail
[91569.773042] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device
[91569.776338] usbcore: registered new interface driver cdc_acm
[91569.776369] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
[92601.131298] usb 1-1.2: USB disconnect, device number 7
[92609.044999] usb 1-1.2: new full-speed USB device number 8 using dwc_otg
[92609.149759] usb 1-1.2: New USB device found, idVendor=2341, idProduct=0043
[92609.149789] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=220
[92609.149806] usb 1-1.2: Manufacturer: Arduino (www.arduino.cc)
[92609.149820] usb 1-1.2: SerialNumber: 74132343430351705051
[92609.156743] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device
pi@raspberrypi ~/Programming/node $

当我尝试运行我的服务器脚本时，我收到错误：

pi@raspberrypi ~/Programming/node $ node server.js
   info  - socket.io started

/home/pi/node_modules/serialport/serialport.js:72
    throw new Error('Invalid port specified: ' + path);
          ^
Error: Invalid port specified: undefined
    at new SerialPort (/home/pi/node_modules/serialport/serialport.js:72:11)
    at Object.<anonymous> (/home/pi/Programming/node/server.js:8:10)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)

我确定我只是遗漏了一些简单的东西，但我不太了解Linux或Node知道它是什么。我需要为驱动程序安装arduino IDE吗？是因为我正在抨击我的覆盆子pi，我知道这使用串口但我想通过USB进行通信。这是可能的还是我只有1个串口，无论是USB还是串口？

编辑我已经安装了IDE，我可以通过IDE与arduino交谈。所以这不是驱动程序或缺少端口。

谢谢你的帮助。

乔

答案

我认为这是因为SerialPort的空参数，你稍后在open中指定

var sp = new SerialPort(); // instantiate the serial port.
//then you open
sp.open(portName, { // portName is instatiated to be COM3, replace as necessary

来自SerialPort npm项目页面

var SerialPort = require("serialport").SerialPort
var serialPort = new SerialPort("/dev/tty-usbserial1");

When opening a serial port, you can specify (in this order).
 1. Path to Serial Port - required.
 2. Options - optional and described below.

所以你应该在SerialPort中指定所有参数而不是open

var portName = '/dev/ttyACM0';
var sp = new SerialPort(portName, {
   baudRate: 115200,
   dataBits: 8,
   parity: 'none',
   stopBits: 1,
   flowControl: false
});

另一答案

我有一个工作nodeJS / arduino / Serialport机器人。

我用过（你需要把串口改成自己的）

  var serialport = require("serialport");
  var SerialPort = serialport.SerialPort; // localize object constructor

  var sp = new SerialPort(comPort, {
     parser: serialport.parsers.readline("
"),
     baudrate: 9600
  });

  sp.on("open", function () {
     sp.write(0x80);
     sp.write('123456
');
     console.log ("comm port ready");
  });

记住当您写入Arduino以“消耗”输出时。我的工作代码，我告诉机器人走向一个特定的方向。

            robotData.setLastCommand(direction);
    sp.write(direction , function(err, results) {
        **sp.drain(function(err, result){**
                //console.log ("drain");
                    //console.log(err, result);
        });
        //console.log ("results -> " + results);
    });

另一答案

也许这段代码可以帮助别人。我在Raspberry PI Zero W上运行它。

它使用解析器获取固定长度的字节（在本例中为16）并检查第一个字符是否为列：

var SerialPort = require('serialport');
var port = new SerialPort('/dev/ttyAMA0', {
   baudRate: 57600,
   dataBits: 8,
   parity: 'none',
   stopBits: 1,
   flowControl: false
});

var ByteLength = require('@serialport/parser-byte-length');
var parser = port.pipe(new ByteLength({length: 16}));


parser.on('data', function (data) {
    var dataUTF8 = data.toString('utf-8');
    if (dataUTF8.substring(0, 1) === ":") {
        console.log('Data: ' + data);
    }
});

注意：这个page对于像我这样在RPI系列上遇到麻烦的人来说非常有用