DHT12 humidity temperature sensor and ESP32 example

DHT12 sensor and ESP32 example

The DHt12 is an upgraded version of the classic DHT11 humidity temperature sensor, it is fully downward compatible, more precise and adds an I2C interface.

Features:

compact size
low power consumption
low voltage operation
Standard I2C and 1-wire interface.

Sensing range
Temperature: -20 ~ +60 C
Humidity: 20-95 RH
Humidity:
Resolution: 0.1%RH
Repeat: -+ 1%RH
Precision 25C @ -+5RH
Temperature:
Resolution: 0.1C
Repeat: -+0.2C
Precision: 25C @ -+0.5C
Power: DC 2.7-5.5V
Normal current 1mA
Standby current 60uA
Sample cycle: > 2 seconds

Pin interface: 1. VDD 2. SDA 3. GND 4. SCL (connect to GND when use as 1-wire)

Parts Required

Here are the parts I used

you can connect to the sensor using a standard header the classic dupont style jumper wire.

Name	Link
ESP32		Aliexpress link Amazon Ebay
DHT12		Aliexpress link Ebay link Amazon Link
Connecting cables		Aliexpress link Amazon Ebay

Layout

This shows how to connect the DHT12 to a Wemos LOLIN32

esp32 and dht12

Code

This is from https://github.com/xreef/DHT12_sensor_library

#include "Arduino.h"

#include <DHT12.h>

// Set dht12 i2c comunication on default Wire pin
DHT12 dht12;

void setup()
{
Serial.begin(112560);
// Start sensor handshake
dht12.begin();
}
int timeSinceLastRead = 0;

void loop()
{
// Report every 2 seconds.
if(timeSinceLastRead > 2000) {
// Reading temperature or humidity takes about 250 milliseconds!
// Read temperature as Celsius (the default)
float t12 = dht12.readTemperature();
// Read temperature as Fahrenheit (isFahrenheit = true)
float f12 = dht12.readTemperature(true);
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h12 = dht12.readHumidity();

bool dht12Read = true;
// Check if any reads failed and exit early (to try again).
if (isnan(h12) || isnan(t12) || isnan(f12)) {
Serial.println("Failed to read from DHT12 sensor!");

dht12Read = false;
}

if (dht12Read){
// Compute heat index in Fahrenheit (the default)
float hif12 = dht12.computeHeatIndex(f12, h12);
// Compute heat index in Celsius (isFahreheit = false)
float hic12 = dht12.computeHeatIndex(t12, h12, false);
// Compute dew point in Fahrenheit (the default)
float dpf12 = dht12.dewPoint(f12, h12);
// Compute dew point in Celsius (isFahreheit = false)
float dpc12 = dht12.dewPoint(t12, h12, false);

Serial.print("DHT12=> Humidity: ");
Serial.print(h12);
Serial.print(" %\t");
Serial.print("Temperature: ");
Serial.print(t12);
Serial.print(" *C ");
Serial.print(f12);
Serial.print(" *F\t");
Serial.print(" Heat index: ");
Serial.print(hic12);
Serial.print(" *C ");
Serial.print(hif12);
Serial.print(" *F");
Serial.print(" Dew point: ");
Serial.print(dpc12);
Serial.print(" *C ");
Serial.print(dpf12);
Serial.println(" *F");
}
timeSinceLastRead = 0;
}
delay(100);
timeSinceLastRead += 100;

}

Output

DHT12=> Humidity: 33.70 % Temperature: 20.20 *C 68.36 *F Heat index: 19.16 *C 66.48 *F Dew point: 3.60 *C 38.48 *F
DHT12=> Humidity: 39.70 % Temperature: 20.60 *C 69.08 *F Heat index: 19.75 *C 67.55 *F Dew point: 6.34 *C 43.41 *F
DHT12=> Humidity: 44.60 % Temperature: 21.20 *C 70.16 *F Heat index: 20.54 *C 68.97 *F Dew point: 8.64 *C 47.55 *F
DHT12=> Humidity: 47.80 % Temperature: 21.80 *C 71.24 *F Heat index: 21.28 *C 70.31 *F Dew point: 10.25 *C 50.45 *F
DHT12=> Humidity: 48.90 % Temperature: 22.40 *C 72.32 *F Heat index: 21.97 *C 71.55 *F Dew point: 11.16 *C 52.08 *F
DHT12=> Humidity: 53.90 % Temperature: 22.90 *C 73.22 *F Heat index: 22.65 *C 72.78 *F Dew point: 13.14 *C 55.66 *F
DHT12=> Humidity: 55.10 % Temperature: 23.60 *C 74.48 *F Heat index: 23.45 *C 74.22 *F Dew point: 14.15 *C 57.46 *F
DHT12=> Humidity: 54.90 % Temperature: 23.90 *C 75.02 *F Heat index: 23.78 *C 74.80 *F Dew point: 14.37 *C 57.86 *F
DHT12=> Humidity: 45.30 % Temperature: 24.40 *C 75.92 *F Heat index: 24.08 *C 75.34 *F Dew point: 11.80 *C 53.24 *F
DHT12=> Humidity: 40.60 % Temperature: 24.60 *C 76.28 *F Heat index: 24.18 *C 75.52 *F Dew point: 10.28 *C 50.50 *F
DHT12=> Humidity: 37.10 % Temperature: 24.80 *C 76.64 *F Heat index: 24.30 *C 75.75 *F Dew point: 9.09 *C 48.35 *F