Hello,
I’m trying to connect together ESP-01 and DHT22,
but after I’m uploading the code to ESP8266,
I’m always got the same repeated error after blynk was connected:
Failed to read from DHT sensor!
I’m tried to use external 3.3/5v for DHT22 but no luck.
I think the problem is in wrong PIN number for GPIO2 in my ESP-01 for DHT. Am I right?
Have no idea how to solve this problem. Please help!
Pinout:
Arduino IDE flashing params:
Code(all ext libraries is the same as links inside the code):
/*************************************************************
Download latest Blynk library here:
https://github.com/blynkkk/blynk-library/releases/latest
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.
Downloads, docs, tutorials: http://www.blynk.cc
Sketch generator: http://examples.blynk.cc
Blynk community: http://community.blynk.cc
Follow us: http://www.fb.com/blynkapp
http://twitter.com/blynk_app
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 Adafruit DHT sensor libraries:
https://github.com/adafruit/Adafruit_Sensor
https://github.com/adafruit/DHT-sensor-library
App project setup:
Value Display widget attached to V5
Value Display widget attached to V6
*************************************************************/
/* Comment this out to disable prints and save space */
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <DHT.h>
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "";
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "YourNetworkName";
char pass[] = "YourPassword";
#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);
BlynkTimer timer;
// 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 setup()
{
// Debug console
Serial.begin(9600);
Blynk.begin(auth, ssid, pass);
// You can also specify server:
//Blynk.begin(auth, ssid, pass, "blynk-cloud.com", 80);
//Blynk.begin(auth, ssid, pass, IPAddress(192,168,1,100), 8080);
dht.begin();
// Setup a function to be called every second
timer.setInterval(1000L, sendSensor);
}
void loop()
{
Blynk.run();
timer.run();
}
Top power rail is 3.3v bottom power rail is 5v
