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I was trying to display the readings of my dht11 sensor on the Blynk dashboard but I am struggling a lot. A little help would be really appreciated.

#define BLYNK_PRINT Serial/* Fill in information from Blynk Device Info here */#define BLYNK_TEMPLATE_ID "TMPL3cu_fjr1u"#define BLYNK_TEMPLATE_NAME "DHT11 Example"#define BLYNK_AUTH_TOKEN "bpPlBa8ehOqw0sJLKJeO1thMlulVXUCY"#include <DHT.h>#include <WiFi.h>#include <WiFiClient.h>#include <BlynkSimpleEsp32.h>// Your WiFi credentials.// Set password to "" for open networks.char ssid[] = "***";char pass[] = "***";#define DHTPIN 2          // What digital pin we're connected to// Uncomment whatever type you're using!#define DHTTYPE DHT11     // DHT 11DHT dht(DHTPIN, DHTTYPE);BlynkTimer timer;// This function sends Arduino's up time every second to Virtual Pin (5)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 setup(){  // Debug console  Serial.begin(9600);  dht.begin();  // Setup a function to be called every second  timer.setInterval(1000L, sendSensor);}void loop(){  Blynk.run();  timer.run();}

When I run this, it gets uploaded with no error, but Blynk shows that the device is offline and this is shown in the serial monitor of Arduino IDE:

15:38:20.658 -> ELF file SHA256: 4b7072eae15:38:20.699 -> 15:38:20.735 -> Rebooting...15:38:20.735 -> �[5001] Connecting to 0.0.0.015:38:26.059 -> 15:38:26.092 -> assert failed: xQueueSemaphoreTake queue.c:1709 (( pxQueue ))15:38:26.181 -> 15:38:26.181 -> 15:38:26.181 -> Backtrace: (some lot of characters)15:38:26.512 -> 15:38:26.512 -> 15:38:26.545 -> 15:38:26.545 -> 15:38:26.545 -> ELF file SHA256: 4b7072eae15:38:26.578 -> 15:38:26.578 -> Rebooting...15:38:26.614 -> ��[5001] Connecting to 0.0.0.015:38:35.107 -> 15:38:35.140 -> assert failed: xQueueSemaphoreTake queue.c:1709 (( pxQueue ))15:38:35.206 -> 15:38:35.206 -> 15:38:35.206 -> Backtrace: (some lot of characters)15:38:35.590 -> 15:38:35.590 -> 15:38:35.590 -> 15:38:35.590 -> 15:38:35.626 -> ELF file SHA256: 4b7072eae15:38:35.626 -> 15:38:35.626 -> Rebooting...15:38:35.668 -> �

Please help

Rohit Gupta's user avatar
Rohit Gupta♦
6342 gold badges6 silver badges21 bronze badges
askedApr 8 at 10:17
KnightRiderDutt's user avatar
2
  • 1
    you don't have the necessary WiFi credentials to connect to your LANCommentedApr 8 at 19:20
  • 1
    @jsotola I do, I have removed them before posting the codeCommentedApr 9 at 6:22

2 Answers2

1

CallBlynk.begin(BLYNK_AUTH_TOKEN, ssid, pass) to establish a WiFi connection first.

SeeESP32_WiFi.ino example.

answeredApr 9 at 2:11
hcheung's user avatar
1

You're missing the Blynk.begin(auth, ssid, pass) call. Without it, Blynk never initializes properly, and that causes the queue/semaphore crash. The setup must look like this:

void setup(){  Serial.begin(9600);  delay(1000); // Give time to serial to initialize  Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);  dht.begin();  timer.setInterval(1000L, sendSensor);}
answeredApr 24 at 16:22
tepalia's user avatar

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