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Integrate Led Status into my DHT Sketch

Hey guys,
I just got my ESP8266. I set up the DHT11 Sensor and got the Code ready. But now i want to have an LED Displaying the Status of the Sensor example Sensor is not working set the Led to Red. But unfortunately it´s not working properly.
Sry for my bad english but it´s not my main language. :slight_smile:
Your Help would be appreciated.

My Code:


    /**************************************************************
     * Blynk is a platform with iOS and Android apps to control
     * Arduino, Raspberry Pi and the likes over the Internet.
     * You can easily build graphic interfaces for all your
     * projects by simply dragging and dropping widgets.
     *
     *
     * Blynk library is licensed under MIT license
     * This example code is in public domain.
     *
     **************************************************************
     * This example shows how value can be pushed from Arduino to
     * the Blynk App.
     *
     * WARNING :
     * For this example you'll need SimpleTimer library:
     *   https://github.com/jfturcot/SimpleTimer
     * and Adafruit DHT sensor library:
     *   https://github.com/adafruit/DHT-sensor-library
     *
     * App project setup:
     *   Value Display widget attached to V5
     *   Value Display widget attached to V6
     *
     **************************************************************/

    #define BLYNK_PRINT Serial    // Comment this out to disable prints and save space
    #include <SPI.h>
    #include <ESP8266WiFi.h>
    #include <BlynkSimpleEsp8266.h>
    #include <SimpleTimer.h>
    #include <DHT.h>

    // You should get Auth Token in the Blynk App.
    // Go to the Project Settings (nut icon).
    char auth[] = "f82eedd4thatsnotmyauth:)4ccf35e3d";

    // Your WiFi credentials.
    // Set password to "" for open networks.
    char ssid[] = "xxxxxxx";
    char pass[] = "xxxxxxxxxx";

    WidgetLED led1(V1);

    BlynkTimer timer;
    bool ledStatus = false;

    #define BLYNK_GREEN   "#23C48E"
    #define BLYNK_RED     "#D3435C"
    #define DHTPIN 2          // What digital pin we're connected to

    // Uncomment whatever type you're using!
    #define DHTTYPE DHT11     // DHT 11
    //#define DHTTYPE DHT22   // DHT 22, AM2302, AM2321
    //#define DHTTYPE DHT21   // DHT 21, AM2301

    DHT dht(DHTPIN, DHTTYPE);


    // This function sends Arduino's up time every second to Virtual Pin (5).
    // In the app, Widget's reading frequency should be set to PUSH. This means
    // that you define how often to send data to Blynk App.
    void sendSensor()
    {
      float h = dht.readHumidity();
      float t = dht.readTemperature(); // or dht.readTemperature(true) for Fahrenheit

      if (isnan(h) || isnan(t)) {
        Serial.println("Failed to read from DHT sensor!");  
        return;
      }
      // You can send any value at any time.
      // Please don't send more that 10 values per second.
      Blynk.virtualWrite(V5, h);
      Blynk.virtualWrite(V6, t);
    }


    void  blinkLedWidget()
    {
      float h = dht.readHumidity();
      float t = dht.readTemperature();
      
      if (isnan(h) || isnan(t)) {
        led1.setColor(BLYNK_RED);
        Serial.println("Led on V1: red");
        ledStatus = true;
      } else {
        led1.setColor(BLYNK_GREEN);
        Serial.println("LED on V1: green");
        ledStatus = false;
      }
    }
    void setup()
    {
      Serial.begin(9600); // See the connection status in Serial Monitor
      Blynk.begin(auth, ssid, pass);

      dht.begin();

      // Setup a function to be called every second
      timer.setInterval(1000L, sendSensor);
    }

    void loop()
    {
      Blynk.run(); // Initiates Blynk
      timer.run(); // Initiates SimpleTimer
    }

Try this:
Blynk.setProperty(V1, “color”, BLYNK_RED);

like this ?


if (isnan(h) || isnan(t)) {
Blynk.setProperty(V1, "color", BLYNK_RED);
Serial.println("Led on V1: red");
ledStatus = true;
} else {
Blynk.setProperty(V1, "color", BLYNK_GREEN);
Serial.println("LED on V1: green");
ledStatus = false;

Exactly. Click on the led widget (i), to get more info on how to use it. The example is like you posted but on the (i) it changed to what I posted

And I can’t find any call to the blinkLedWidget() function.
You must insert another timer to do it:
timer.setInterval(1000L, blinkLedWidget);
But you could just use the same sendSensor function to check the availability of the sensor data and change the led color accordingly

@J4ck I may be mistaken, but I do not see your blinkLedWidget() function being called anywhere. You need to add a timer, timer.setInterval(1000L, blinkLedWidget);

Or, you could eliminate this blinkLedWidget() function and just add the color changing command to the first IF statement, since it is the same conditions, if (isnan(h) || isnan(t)).


void sendSensor(){

float h = dht.readHumidity();
float t = dht.readTemperature(); // or dht.readTemperature(true) for Fahrenheit

if (isnan(h) || isnan(t)) {
Blynk.setProperty(V1, "color", BLYNK_RED);
Serial.println("Failed to read from DHT sensor!");
Serial.println("Led on V1: red");
ledStatus = true;
} else {
Blynk.setProperty(V1, "color", BLYNK_GREEN);
Serial.println("Received reading from DHT sensor!");
Serial.println("LED on V1: green");
ledStatus = false;
}
// You can send any value at any time.
// Please don't send more that 10 values per second.
Blynk.virtualWrite(V5, h);
Blynk.virtualWrite(V6, t);
}

I type too slow. I see you had already advised exactly what I was thinking.

Ha! Jinx! :wink:

Where should i insert timer.setInterval(1000L, blinkLedWidget); ?

but i need to #define BLYNK_GREEN and stuff right ?

Thank you anyway :blush: )

Yes you will need to include the #define for the colors you wish to use.

As for the timer.setInterval(1000L, blinkLedWidget); it should go right before or after timer.setInterval(1000L, blinkLedWidget); in your setup function.

Just write the new timer after the other one:

timer.setInterval(1000L, sendSensor);
timer.setInterval(1000L, blinkLedWidget);

Or just copy the code from @Toro_Blanco and get rid of the blinkLedWidget function

1 Like

Clean up your code and post it here but use this trick:

1 Like

Thanks already did it :slight_smile:

It´s kinda working now, but it´s switching between Received Reading and Failed to Read
it displays this in serial monitor
Failed to read from DHT sensor!
Led on V1: red
Failed to read from DHT sensor!
Led on V1: red
Received reading from DHT sensor!
LED on V1: green
Received reading from DHT sensor!

The Led on the App isn´t lighting up aswell.

You will probably need turn the led on. Add this before the if statement.

led1.on(); //turn on led

Once it receives the reading from the sensor does it continue to receive the readings or does it then fail to receive after that?

Re-post the code you are now using so we can have a look.

Everything is working now but still switching between states some times it stays then it switches to failed again can´t see any patterns

 /**************************************************************
 * Blynk is a platform with iOS and Android apps to control
 * Arduino, Raspberry Pi and the likes over the Internet.
 * You can easily build graphic interfaces for all your
 * projects by simply dragging and dropping widgets.
 *
 * Blynk library is licensed under MIT license
 * This example code is in public domain.
 *
 **************************************************************
 * This example shows how value can be pushed from Arduino to
 * the Blynk App.
 *
 * WARNING :
 * For this example you'll need SimpleTimer library:
 *   https://github.com/jfturcot/SimpleTimer
 * and Adafruit DHT sensor library:
 *   https://github.com/adafruit/DHT-sensor-library
 *
 * App project setup:
 *   Value Display widget attached to V5
 *   Value Display widget attached to V6
 *
 **************************************************************/

#define BLYNK_PRINT Serial    // Comment this out to disable prints and save space
#include <SPI.h>
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h>
#include <DHT.h>

WidgetLED led1(V1);

BlynkTimer timer;
bool ledStatus = false;

#define BLYNK_GREEN   "#23C48E"
#define BLYNK_RED     "#D3435C"
#define DHTPIN 2          // What digital pin we're connected to

// Uncomment whatever type you're using!
#define DHTTYPE DHT11     // DHT 11
//#define DHTTYPE DHT22   // DHT 22, AM2302, AM2321
//#define DHTTYPE DHT21   // DHT 21, AM2301

DHT dht(DHTPIN, DHTTYPE);


// This function sends Arduino's up time every second to Virtual Pin (5).
// In the app, Widget's reading frequency should be set to PUSH. This means
// that you define how often to send data to Blynk App.
void sendSensor(){

float h = dht.readHumidity();
float t = dht.readTemperature(); // or dht.readTemperature(true) for Fahrenheit
led1.on(); //turn on led
  
  if (isnan(h) || isnan(t)) {
Blynk.setProperty(V1, "color", BLYNK_RED);
Serial.println("Failed to read from DHT sensor!");
Serial.println("Led on V1: red");
ledStatus = true;
  } else {
Blynk.setProperty(V1, "color", BLYNK_GREEN);
Serial.println("Received reading from DHT sensor!");
Serial.println("LED on V1: green");
ledStatus = false;
  }
// You can send any value at any time.
// Please don't send more that 10 values per second.
Blynk.virtualWrite(V5, h);
Blynk.virtualWrite(V6, t);
}


void setup()
{
  Serial.begin(9600); // See the connection status in Serial Monitor
  Blynk.begin(auth, ssid, pass);

  dht.begin();

  // Setup a function to be called every second
  timer.setInterval(1000L, sendSensor);
}

void loop()
{
  Blynk.run(); // Initiates Blynk
  timer.run(); // Initiates SimpleTimer
}

Are the readings on v5 and v6 accurate?

Maybe try increasing the timer interval.