Send json from arduino and esp8266 to node.js socket server

Question

I've been trying to send JSON data from arduino mega by using ESP8266 as a wifi shield, and I've used node.js as a socket server. The problem is it seems that a server didn't receive any data. here is my code

   #include <ArduinoJson.h>
#include "SoftwareSerial.h"


String ssid ="ssid";
String password="pwd";
//SoftwareSerial esp(22,23);// RX, TX
String data;
String server = "server ip"; 
byte objlength;
String url = "";
String temp,hum,weight;
StaticJsonBuffer<200> jsonBuffer;
JsonObject& root = jsonBuffer.createObject();
//String uri = "yourURI";

void reset() {

Serial2.println("AT+RST");
delay(1000);
if(Serial2.find("OK") ) Serial.println("Module Reset");


}
void connectWifi() {

String cmd = "AT+CWJAP=\"" +ssid+"\",\"" + password + "\"";
Serial2.println(cmd);
delay(4000);

if(Serial2.find("OK")) {
Serial.println("Connected!");
Serial2.println("AT+CIPSTATUS");
delay(300);
while(Serial2.available()){Serial.print(Serial2.read());}

}
else {
connectWifi();
Serial.println("Cannot connect to wifi"); }
}

void setup() {
delay(5000);
  // put your setup code here, to run once:
Serial2.begin(115200);
Serial.begin(115200);
reset();
connectWifi();

}


void loop() {
temp = 25.60;
hum = 65.3;
weight = 65.3;

root["weight"] = weight;
root["light"] = temp;
root["humid"] = hum;
objlength = root.measureLength();
senddata();
delay(10000);
}
void senddata() 
{
int objlength = root.measureLength();

Serial2.println("AT+CIPSTART=\"TCP\",\"" + server + "\",1336");//start a TCP connection.

delay(500);
if( Serial2.find("OK")) {
Serial.println("TCP connection ready");
} 
else
{
Serial.println("can't establish TCP connection");
}
String sendCmd = "AT+CIPSEND=";//determine the number of caracters to be sent.

Serial2.println(sendCmd);
delay(200);
Serial2.println(objlength);

delay(500);

if(Serial2.find(">")) 
{ 
Serial.println("Sending..");
root.printTo(Serial2);
root.printTo(Serial);
//Serial.println(postRequest);
  delay(2000);
  if( Serial2.find("SEND OK")) 
  { 
    Serial.println("Packet sent");
    delay(200);

    while (Serial2.available()) {
    String tmpResp = Serial2.readString();
    Serial.println(tmpResp);
  }
// close the connection

  }
 //delay(1000);
Serial2.print("+++");
delay(1200);
Serial2.println("AT+CIPCLOSE");
delay(50);
Serial.println("Closed");
}

}

Here's my node.js

var net = require('net');

var server = net.createServer(function(socket){
    socket.write('SEND OK');
//
    socket.pipe(socket);

socket.on('data',function(data){
    //if(typeof data != 'string'){
    var jsontest = JSON.parse(data);
    console.log('Received: ' + data);
    console.log(jsontest.weight);
    console.log(jsontest.light);
    console.log(jsontest.humid);
    //}
    });
socket.on('listening',function(){
    console.log(listen);
});
});
/*server.getConnections(function(err,count){
console.log(count);
});*/
server.listen(1336, '10.42.0.1');

I think that esp8266 can establish a connection with a server , but I don't know why the data won't show. Maybe it's about esp8266 respond time? screenshot As you can see from this screenshot, I run node.js server and arduino ,but data won't show on server side. Due to this,I'm not sure where are the problems that cause this.

Answer 1

I'm not an expert. I'm just learning how to do it but i'd say you are not giving enough time through connections. You are relying on delays rather than timeouts while waiting for a true response. There is a difference.

Add much more time or change your strategy by using serial.available() and read in a loop that last a prudential amount of time, and exit when you got data.

Sorry no pasting some code, but i hope you got the idea.

Also i'm facing a power problem. 3,3v pin in arduino uno could be weak in clone boards. But i dont think that's the case.