Alibaba cloud development board haas510 sends the serial port data to the Internet of things platform

Abstract ： Alibaba cloud HaaS510 Development board to 4G Network form networking , Can get rid of wifi rely on , So it can be widely used in the development of all kinds of Internet of things devices . As a module specially used to communicate with Alibaba cloud Internet of things platform , It has a basic and powerful function is to pass the data or instructions obtained through the serial port 4G The network sends it to the Internet of things platform , adopt JavaScript In very short code .

The experiment purpose ： adopt haas510 Receive the serial port instructions from the upper computer , Send it as the attribute value of the IOT device .

Hardware ：haas510 (2.0 edition ）,USB A serial port

Software ：win7 x64,vscode

Catalog

1. Common Internet of things platforms JavaScript Method

 2. Report device attributes json String handling methods

3. Write the report attribute source code

4. Observe the experimental effect

---

1. Common Internet of things platforms JavaScript Method

Common methods are “ Escalation properties ”“ Report the incident ”, And then there is “ Close instance ”“ Register callback function ” etc. .

  This experiment uses postProps Method . The function of this method is to report device attributes . Parameter only 1 individual , It's attribute json Format string . This is in a fixed format , If the format is incorrect, it cannot be reported normally . Generally, it is the attribute name -- The colon --- Property value , But it has to be handled , Please continue to read this article for specific handling methods .

 2. Report device attributes json String handling methods

Suppose our device attribute is text type , The identifier is beizhu.

  So a standard attribute string is       {"beizhu":"xxxxxxxx"}

Use JavaScript When a program reports this property , You cannot predict in advance what data the serial port receives , Therefore, a complete string cannot be directly sent to the IOT platform .

The correct way is to get the serial port data , And half a string . The specific code is

JSON.stringify({beizhu:ArrayToString(data)})

data Is the data received by the serial port , adopt stringify Repeatedly convert the string including curly braces into a complete string json String .

json What is it? ？

JSON = JavaScript Object Notation, Some translated as JS Object shorthand

It can be seen from the literal meaning that it is JavaScript My son ,JavaScript It is supported by default .

This means that JavaScript In dealing with JSON Data doesn't need any special API Or toolkit .

This experiment uses stringify Method , Because it's native , So the amount of code is very small .

3. Write the report attribute source code

This article directly contributes the debugged source code , You can copy and paste .

var iot = require('iot');
var network = require('network');
var uart = require('uart');
var net = network.openNetWorkClient();
/*  For information about device triples, please refer to common In the catalog iot Component description  */
var productKey = 'gcXXXXXvu2';
var deviceName = 'cewSSSSS001';
var deviceSecret = 'ee213aSSSSSSSSSadcdedb3a9';
//  Build Internet of things connection instances 
var device;
var lightSwitch = 0;
 
 
  //  Open the user serial port , stay HaaS in , The serial port number of the user is UART2
  var serial = uart.open({
    id: 'UART2'
  });
 
  var msgbuf = [97, 98, 99, 100];
 
  function ArrayToString(fileData) {
    var dataString = "";
    for (var i = 0; i < fileData.length; i++) {
      dataString += String.fromCharCode(fileData[i]);
    }
    return dataString;
  }
 
//net.on It is used to connect the IOT platform with triple data , The core is to implement a MQTT client 
net.on('connect', function () {
    device = iot.device({
        productKey: productKey,
        deviceName: deviceName,
        deviceSecret: deviceSecret,
        region: 'cn-shanghai',
        success: function () {
            console.log('iot: [success] connect');
        },
        fail: function () {
            console.log('iot: [failed] connect');
        }
    });
})
// Timing procedure , This program implements 5 Second timing , Turn the status of the main light switch every time , Send an array of data to the user serial port 
// Then send the main light switch status to the Internet of things platform 
setInterval(function () {
    lightSwitch = 1 - lightSwitch;
 
    // user uart send data
    serial.write(msgbuf);
    
 
/*  Error model    iot.postProps({
                       payload: {LightSwitch:'0'}
                    })*/
/* Correct demonstration , To send attributes , You have to use stringify Talent */
    device.postProps(
        JSON.stringify({
            LightSwitch: lightSwitch
        })
    );
  
  }, 5000);
 
 
// serial.on Used to respond to serial port data receiving events , What does the user receive through the serial port , Just send notes to the IOT platform through the debugging serial port .
// Be careful , The two serial ports are not the same .
serial.on('data', function(data) {
  console.log('uart receive data is ' + ArrayToString(data));
  device.postProps( 
                  JSON.stringify({
                  beizhu: ArrayToString(data)
                                 })
                   );
});

4. Observe the experimental effect

The hardware connection is shown in the figure below

The experimental results are presented in the following aspects .

First, the device will be online , This is net.on Realized

Secondly, the serial port of the user will be timed 5 Seconds to send 4 Characters （ It's actually an array ） To the upper computer , This is setInterval Realized .

Then when the upper computer sends a string through the serial port ,HaaS510 This string will be sent to the Internet of things platform , As beizhu The value of the property .

  thus , Successful experiment .

One deficiency is that ： When the Internet of things devices are designed only 1 When there are two attributes , In this way, the serial port data can be directly sent to the Internet of things platform . But in the actual R & D work , The attributes of each device cannot have only one attribute , It often has many properties . If you simply report the serial port data as a string , Obviously, it is not what a mature device should have .

therefore , We also need to parse the data sent from the serial port , Extract the value of each attribute , And then send it to the cloud platform .

This is what we need to do next .