Device sometimes offline or does not display value

Need Help With My Project
1

Hi, I am using the WeMos D1 Mini and DHT22 Sensor for my project. I have added 2 devices on my Blynk app, each device has it’s own tab which comes with a gauge and super chart to display the data

I have no clue as to why Device 1 is sometimes online, sometimes offline whereas Device 2 is able to display the data. At times, even when Device 1 is online, the widgets will still not be working… as shown below:

I have tried to work Device 1 alone, it does not work too. Device 1 comes online sometimes but the temperature value still does not appear. It either goes to ‘nan’ or no value. I have tried to change the sensors, wires, cables and even WeMos but it still doesn’t work…

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//DEVICE -1

/*PINS

  V0 =
  V1 = Table
  V2 =
  V3 =
  V4 = Stations Selections
  V5 = LCD
  V6 =
  V7 =
  V8 = RoS1
  V9 = RoS2
  V10= RoS3
  V11 = T1 (Device 1)
  V12 = T2 (Device 2)
  Setpoints = V21(Device 1), V22(Device 2)

*/

//All required libraries
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include "DHT.h"
#define DHTTYPE DHT22
#define dht_dpin D4
DHT dht(dht_dpin, DHTTYPE);

//All variables with their data types
float setpoint1;
int station, RoS1;
int prevValue, pRoS1;



//Your Auth Token
char auth[] = "zQ5IZJvjq3JHkMJrA5_VAYqyRiOrn_l";

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


//For BLYNK LCD
WidgetLCD lcd(V5);

//Assigning values to some variables coming from BLYNK Virtual Pins
BLYNK_WRITE(V4)
{
  station = param.asInt(); // assigning incoming value from pin V4 to a variable
}
BLYNK_WRITE(V8)
{
  RoS1 = param.asInt(); // assigning incoming value from pin V8 to a variable
}
BLYNK_WRITE(V21)
{
  setpoint1 = param.asFloat();
}




void setup()
{
  Blynk.begin(auth, ssid, pass);
  dht.begin();
  Serial.begin(9600);
}

void loop()
{
  Blynk.run();


  prevValue = station;
  pRoS1 = RoS1;

  if (station == 1) {
    //lcd.print(col, row, "TEXT"/VARIABLE );
    lcd.print(0, 0, "Station = 1");
    lcd.print(0, 1, "Rooms =");
    lcd.print(8, 1, RoS1);
    float t = dht.readTemperature();
    Blynk.virtualWrite(V11, t);
    Blynk.virtualWrite(V1, "add", 1, "TEMPERATURES", "SETPOINTS" );
    Blynk.virtualWrite(V1, "add", 2, t , setpoint1);
    
  }
  else if (station == 2) {
    lcd.print(0, 0, "Station = 2");
    Blynk.virtualWrite(V1, "clr");
    Blynk.virtualWrite(V11, 0);
  }

}
2

Clean up your loop() It should look like this:

void loop()
{
  Blynk.run(); // all the Blynk magic happens here
  timer.run(); // BlynkTimer is working...
}

Search the forum!! The DHT sensors have probably been discussed a gazillion times…

3

I’ve deleted your other topic on this subject. Please don’t create multiple topics for the same issue in future.
I’ve also changed this from “Issues and Errors” which is used for bugs in the Blynk app or library, to “Need help…”.

Did you try regenerating the Auth code as I suggested in the previous topic?
Have you checked that the widgets that Device 1 is meant to be updating when it does go online are actually attached to the correct device?

Pete.

4

Yes, I have regenerated a new Auth code and have checked all connections but the device is still offline otherwise there is no value.

5

Pete.

6

Yes. May i know the reason why the device is offline most of the time?

7

Based on the information you’ve provided, I have no idea.

Pete.

8

Take a look at the loop Pete :joy:

2 Likes
9

@distans gave you the solution !