Data is sent but not update

I write the code to sent the humidity and temperature from sensor to ThingSpeak. The data is sent but the field grap is not updating. I write code on nodeMCU.

#include <ESP8266WiFi.h>
#include <DHT.h>

//PIN
int FAN_PIN = 0;
int WATER_PIN = 2;
#define DHTTYPE DHT11

//variable
DHT dht;
float tempsetting = 28;
float humidsetting = 80;

//Wifi variables
String apiKey = "xxxxxxxxxxxxxxxx";     //Write API key
long channelID = 1872808;
const char* server = "api.thingspeak.com";

const char* ssid =  "Chan family_2G";
const char*pass =  "yyyyyyyyyyy";

WiFiClient client;

void setup() {
  Serial.begin(9600);
  delay(500);
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  WiFi.begin(ssid, pass);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");

  dht.setup(16);
}

void loop() {
  delay(dht.getMinimumSamplingPeriod());
  float humidity = dht.getHumidity();
  float temperature = dht.getTemperature();
  pinMode(FAN_PIN, OUTPUT);
  pinMode(WATER_PIN, OUTPUT);
  function();
  cloud();
}

void function() {
  float humidity = dht.getHumidity();
  float temperature = dht.getTemperature();

  Serial.print(dht.getStatusString());
  Serial.print("\tHumidity :");
  Serial.print(humidity, 1);
  Serial.print("\t\tTemp C:");
  Serial.println(temperature, 1);
  
  if (humidity >= humidsetting) {
    digitalWrite(WATER_PIN, LOW);
    Serial.print("Water OFF");
  }
  else {
    digitalWrite(WATER_PIN, HIGH);
    Serial.print("Water ON");  
  }
  
  if (temperature <= tempsetting) {
    digitalWrite(FAN_PIN, LOW);
    Serial.println("\tFan OFF"); 
  }
  else {
    digitalWrite(FAN_PIN, HIGH); 
    Serial.println("\tFan ON");   
  } 

  delay(2000);
}

void cloud() {
  float humidity = dht.getHumidity();
  float temperature = dht.getTemperature(); 
  String Humidity = String(humidity);
  String Temperature = String(temperature);
   
  if (isnan(temperature) || isnan(humidity)){
    Serial.println("Failed to read value from sensor!");
    return;
  }

  // Connect to ThingSpeak
  WiFiClient client;
  const int httpPort = 80;
  if (!client.connect("api.thingspeak.com", httpPort)) {
    Serial.println("Failed to connect to ThingSpeak");
    return;
  }

  // Build the URL for the request
  String url = "/update?api_key=";
  url += apiKey;
  url += "&field1=";
  url += String(humidity);
  url += "&field2=";
  url += String(temperature);


  // Make the HTTP GET request
  if (client.connect(server,80)) {
    client.print("POST /update HTTP/1.1\n"); 
    client.print("Host: api.thingspeak.com\n"); 
    client.print("Connection: close\n"); 
    client.print("X-THINGSPEAKAPIKEY: "+apiKey+"\n"); 
    client.print("Content-Type: application/x-www-form-urlencoded\n"); 
    client.print("\n\n");
  }
  
  // Wait for the response from ThingSpeak
  int timeout = millis();
  while (client.available() == 0) {
    if (millis() - timeout > 5000) {
      Serial.println("Timeout while reading response from ThingSpeak");
      client.stop();
      return;
    }
  }

  // Close the connection to ThingSpeak
  client.stop();

  Serial.println(); 
  Serial.print("Humidity: "); 
  Serial.print(humidity);
  Serial.print("% and Temperature: "); 
  Serial.print(temperature);
  Serial.println(" send to ThingSpeak");    

  Serial.println("Waiting...");
  Serial.println();  
  Serial.println();  
  
  // Wait for a short period before sending the next request
  delay(20000);
}

Answer 1

[Christopher Stapels]

Is seems that you are building the url but never sending it to ThingSpeak. This would explain why neither method works. I would recomend switching to the ThingSpeak library, but you could also add lines line these to your post.

client.println( "Content-Length: " + String( url.length() ) );
client.println();
client.println( url );

You can compare to this soil moisture example.

[Panithan Chantubtim]

It's work!! Thanks a lot.

Answer 2

[Christopher Stapels]

We suggest using the ThingSpeak library for Arduino, when you can.

The next thing I would suggest is to see if you can update your channel using a web browser in the address field. See the API keys tab on you channel view for the correct format. You can use the read data fromat on the same tab to see if any data is being written to ThingSpeak, even if your plots are not showing the data. This will allow you to see if the sensor is working or if there is some other spurious data.

Then use your code to write a fixed string or number (not the sensor value) to ThingSpeak. Like this:

  // Build the URL for the request
  String url = "/update?api_key=";
  url += apiKey;
  url += "&field1=25";   
  

Then see if the value of 25 shows up in your channel.

[Panithan Chantubtim]

No, the number is not show up in my channal but the entries number went up.

[Christopher Stapels]

Can you describe in more detail what you tried? There were several suggestions in my post.

If the number of entries went up but you dont see data in the field plots, that usually means you are writing blank or string data to ThingSpeak. You can see the data that you wrote by reading back the data, as I described above.

The read API has this format

https://api.thingspeak.com/channels/949687/feeds.json?api_key=xxxxxxxxxxxxxxxx&results=2

[Panithan Chantubtim]

I change the code to the fixed number like you suggest and it is not update in channal.

[Christopher Stapels]

Were you able to update the channel using the read API in the web browser?

[Panithan Chantubtim]

I can send the data using update API in web