Arduino can't show out respond get from mqtt server through esp8266 - arduino

Question

I'm trying to let my Arduino and esp8266 send data to thingsboard and then subscribe to thingsboard's mqtt channel and get a timestamp from it but for some unknown reason, it just doesn't work. Checked server-side and it was ok, tried postman to simulate request and also getting the correct response from the server.
Also, I had read the documentation about esp8266 and it somehow did state that it only can have 1 connection simultaneously. But tried to let my Arduino to only subscribe to channel but it still doesn't work.
My code:(I'm using Arduino Mega for this)
#include "DHT.h"
#include <WiFiEspClient.h>
#include <WiFiEsp.h>
#include <WiFiEspUdp.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
#include <TimeLib.h>
#define WIFI_AP "CEC"
#define WIFI_PASSWORD "#CEC#2017#CEC#"
#define TOKEN "A1_TEST_TOKEN"
// DHT
#define DHTPIN 2
#define DHTTYPE DHT22
char thingsboardServer[] = "192.168.0.250";
// Initialize the Ethernet client object
WiFiEspClient espClient;
// Initialize DHT sensor.
DHT dht(DHTPIN, DHTTYPE);
PubSubClient client(espClient);
int status = WL_IDLE_STATUS;
unsigned long lastSend;
unsigned long lastSync;
void setup() {
// initialize serial for debugging
Serial.begin(9600);
Serial1.begin(9600);
Serial2.begin(9600);
//serial pin
pinMode(LED_RUN_pin, OUTPUT);
//dht.begin();
InitWiFi();
lastSend = 0;
lastSync = 0;
//client subscribe thingsboard rpc PUBLISH msg
client.setServer( thingsboardServer, 1883 );
client.setCallback(on_message);
}
void loop() {
status = WiFi.status();
if ( status != WL_CONNECTED) {
while ( status != WL_CONNECTED) {
Serial.print("Attempting to connect to WPA SSID: ");
Serial.println(WIFI_AP);
// Connect to WPA/WPA2 network
status = WiFi.begin(WIFI_AP, WIFI_PASSWORD);
delay(500);
}
}
if ( !client.connected() ) {
reconnect();
}
if ( millis() - lastSend > 30000 ) { // Update and send after 30 seconds
getAndSendTemperatureAndHumidityData();
lastSend = millis();
}
client.loop();
}
void getAndSendTemperatureAndHumidityData()
{
Serial.println("Collecting temperature data.");
// Reading temperature or humidity takes about 250 milliseconds!
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float t = dht.readTemperature();
// Check if any reads failed and exit early (to try again).
if (isnan(h) || isnan(t)) {
Serial.println("Failed to read from DHT sensor!");
return;
}
Serial.print("Humidity: ");
Serial.print(h);
Serial.print(" %\t");
Serial.print("Temperature: ");
Serial.print(t);
Serial.print(" *C ");
String temperature = String(t);
String humidity = String(h);
// Prepare a JSON payload string
String payload = "{";
payload += "\"temperature\":"; payload += temperature; payload += ",";
payload += "\"humidity\":"; payload += humidity;
payload += "}";
// Send payload
char attributes[100];
payload.toCharArray( attributes, 100 );
client.publish( "v1/devices/me/rpc/request/1", attributes , 1);
//Serial.println( attributes );
}
// Prepare a JSON payload string
String payload = "{method: getTime, params:{}}";
// Send payload
char attributes[100];
payload.toCharArray( attributes, 100 );
client.publish( "v1/A1_TEST_TOKEN/rpc", attributes );
//Serial.println( attributes );
}
void InitWiFi()
{
// initialize serial for ESP module
Serial1.begin(9600);
// initialize ESP module
WiFi.init(&Serial1);
// check for the presence of the shield
if (WiFi.status() == WL_NO_SHIELD) {
Serial.println("WiFi shield not present");
// don't continue
while (false);
}
Serial.println("Connecting to AP ...");
// attempt to connect to WiFi network
while ( status != WL_CONNECTED) {
// Connect to WPA/WPA2 network
status = WiFi.begin(WIFI_AP, WIFI_PASSWORD);
delay(500);
}
}
void reconnect() {
// Loop until we're reconnected
while (!client.connected()) {
//Serial.print("Connecting to Thingsboard node ...");
// Attempt to connect (clientId, username, password)
if ( client.connect("Arduino Uno Device", TOKEN, NULL) ) {
Serial.println( "[DONE]" );
delay(500);
// Serial.println("Subscribing RPC");
client.subscribe("v1/devices/me/rpc/request/+");
} else {
Serial.print( "[FAILED] [ rc = " );
Serial.print( client.state() );
Serial.println( " : retrying in 20 seconds]" );
// Wait 20 seconds before retrying
delay( 20000 );
}
}
}
void printDigits(int digits){
// utility function for digital clock display: prints preceding colon and leading 0
Serial.print(":");
if(digits < 10)
Serial.print('0');
Serial.print(digits);
}
// The callback for when a PUBLISH message is received from the server.
void on_message (char* topic, byte* payload, unsigned int length) {
//Serial.println("On message");
char json[length + 1];
strncpy (json, (char*)payload, length);
json[length] = '\23';
Serial.print("Topic: ");
Serial.println(topic);
Serial.print("Message: ");
Serial.println(json);
// Decode JSON request
StaticJsonBuffer<200> jsonBuffer;
JsonObject& data = jsonBuffer.parseObject((char*)json);
if (!data.success())
{
Serial.println("parseObject() failed");
return;
}
}

Answer 1

Probably a stupid remark, but is your TOKEN a valid Thingsboard device token? I assume you entered the value A1_TEST_TOKEN to hide your real authentication token.
I also assume you are trying to send sensor data (telemetry) to Thingsboard. Why did you decide to use the RPC API for sending data? I think it might be easier to use the MQTT Device API instead.
I don't have any experience in developing for Arduino. I am using Thingsboard together with a Raspberry PI to write and display sensor data. Hope you find a solution for your problem!