A simple project to learn IoT by connecting a DHT11 temperature and humidity sensor with WeMos D1 Mini and interfacing the data to Blynk.

Step 3: Set Up Blynk

After download and installing the Blynk Apps from Google Play Store, you need to make your IoT project apps in Blynk. Here the steps.

• Login to your Blynk App. If you don’t have one, just create it, it’s free
• Create a new project, give your project a name, choose your device : WeMos D1 Mini, connetion type : WiFi
• Then you will receive a notification about Auth Token, just select OK. Your Auth Token wil be sent to your Email
• Then you see your workspace. Go to Widget Box, and select ‘Gauge’. Select the Gauge Widget twice, the first one will be set as the Temperature gauge, the second one will be set as the Humidity gauge.
• After two gauge selected, go to the gauge setting.

For the first gauge:

Name: Temperature

Input: Virtual, V0

Label: °C / °F

Reading Rate: 1 Sec

For the second gauge:

Name: Humidity

Input: Virtual, V1

Label: RH

Reading Rate: 1 Sec

Step 4: Code

Paste the code that i’ve attached, and change the auth code in the program that i’ve attached with your own auth code (check your Email for your auth code).https://www.hackster.io/fattahalf

#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include "DHT.h"
#include <SimpleTimer.h> 
#define DHTTYPE DHT11
#define dht_dpin D4
DHT dht(dht_dpin, DHTTYPE); 
SimpleTimer timer;
char auth[] = "Your Auth Code";
char ssid[] = "Your WiFI";
char pass[] = "Your Wifi Password";
float t;
float h;

void setup()
{
    Serial.begin(9600);
    Blynk.begin(auth, ssid, pass);
    dht.begin();
    timer.setInterval(2000, sendUptime);
}

void loop()
{
  Blynk.run();
  timer.run();
}

void sendUptime()
{
  float h = dht.readHumidity();
  float t = dht.readTemperature(); 
  Serial.println("Humidity and temperature\n\n");
  Serial.print("Current humidity = ");
  Serial.print(h);
  Serial.print("%  ");
  Serial.print("temperature = ");
  Serial.print(t); 
  Blynk.virtualWrite(V0, t);
  Blynk.virtualWrite(V1, h); 
}