Display on the I2C LCD display the temperature and humidity measured by DHT22 connected to ESP32

ESP32 30-01-24

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Tutorial plan

1- How to use the DHT22 sensor by the ESP32 board?

2- The components required to use the DHT22 sensor and I2C LCD display by ESP32 board

3- Mounting the ESP32 board with the DHT22 sensor and the I2C LCD display

4- Program ESP32 with MicroPython to display the temperature and humidity measured by the DHT22 on the I2C LCD display

How to use the DHT22 sensor by the ESP32 board ?

The DHT22 sensor is a digital temperature and humidity sensor that is commonly used in electronics projects for monitoring environmental conditions.This sensor comes in a small package with four pins, and it utilizes a digital signal to communicate temperature and humidity readings to a microcontroller or a computer. The DHT22 sensor is relatively simple to use and can be found in various applications like weather stations, home automation systems, and humidity control devices.

The ESP32 is a powerful microcontroller board that’s widely used in IoT (Internet of Things) and embedded systems development.

Here’s a breakdown of how sensors can be used with ESP32 board:

1- Hardware Connections:

Power: Connect the DHT22 sensor’s power (+) and ground (-) pins to the ESP32’s 3.3V and GND pins, respectively.

Data/Signal: the DHT22 sensor have OUR pin. Connect this pin to any digital or analog pin on the ESP32 (refer to the sensor’s datasheet for specific pin connections).

2- MicroPython (Code):

Utilize MicroPython’s programming language (based on Python) to interface with the sensor.

Use libraries (if available) specific to the DHT22 sensor to simplify code and access sensor readings. For instance, the DHT library for DHT temperature and humidity sensors.

Reading Sensor Data: In the MicroPython program, you’ll write code to read data from the sensor. This might involve initializing the DHT22 sensor, reading digital values, and interpreting sensor outputs into meaningful data (temperature and humidity).

3- Processing Sensor Data: Display the sensor data on an LCD screen connected to the ESP32 board.

The components required to use the DHT22 sensor and I2C LCD display by ESP32 board

To display the temperature and humidity readings from the DHT22 sensor on an I2C LCD display using the ESP32 board, you’ll need the following components:

ESP32 board:

ESP32 card

The ESP32 is a powerful microcontroller developed by Espressif Systems. It’s renowned for its integrated Wi-Fi and Bluetooth capabilities, making it a popular choice for various IoT (Internet of Things) applications.

It is the central control unit for your project.

DHT22 Temperature and Humidity Sensor

DHT22

The DHT22 is a basic, low-cost digital temperature and humidity sensor.

I2C LCD Display (usually 16×2)

This display is used for displaying the temperature and humidity from the DHT22 sensor .

Jumper Wires:

Jumper wires

For making temporary connections and wiring between components.

Breadboard:

Test plate

A breadboard is a useful tool for creating temporary electronic circuits. It allows you to connect components without soldering.

Mounting the ESP32 board with the DHT22 sensor and the I2C LCD display

Mounting the ESP32 board along with the DHT22 sensor and I2C LCD display can be done in various ways based on the preferences for the project’s permanence, aesthetics, and convenience. Here’s a suggestion on how to mount them:

Attaching the I2C LCD Display :

– connect the VCC pin of the display to 5V pin of the ESP32

– connect the GND pin of the display to GND pin of the ESP32

– connect the SDA pin of the display to GPIO21 pin of the ESP32

– connect the SCL pin of the display to GPIO22 pin of the ESP32

Mounting the DHT22 Sensor:

– connect the VCC(+) pin of the DHT22 Sensor to 3.3V pin of the ESP32

– connect the GND(-) pin of the DHT22 to GND pin of the ESP32

– connect the OUT pin of the DHT22 to GPIO23 of the ESP32

Mounting the ESP32 board with the DHT22 sensor and the I2C LCD display

Program ESP32 with MicroPython to display the temperature and humidity measured by the DHT22 on the I2C LCD display

To display the temperature and humidity measured by the DHT22 sensor on an I2C LCD display using the , follow these steps:

1- Ensure you have MicroPython firmware installed on your ESP32 board using this file esp32-20210902-v1.17.bin.

2- Ensure you have the necessary libraries installed: dht, ‘i2c_lcd‘ and ‘lcd_api‘

3- Use this code to read from the DHT22 sensor and display the temperature and humidity on the I2C LCD display.

import machine
from machine import Pin, SoftI2C
from lcd_api import LcdApi
from i2c_lcd import I2cLcd
from time import sleep
import dht

I2C_ADDR = 0x27
totalRows = 2
totalColumns = 16
#initializing the I2C method for ESP32
i2c = SoftI2C(scl=Pin(22), sda=Pin(21), freq=10000)     
lcd = I2cLcd(i2c, I2C_ADDR, totalRows, totalColumns)
# Define DHT22 sensor pin
p23=Pin(23, Pin.IN)
# Initialize DHT22 sensor
d=dht.DHT22(p23)

while True:
    d.measure() #Measurement of temperature and humidity
    t=d.temperature() #read temperature
    h=d.humidity() #read humidity
    lcd.clear()
    #display temperature on LCD display 
    lcd.putstr("tempertature:"+str(int(t)))
    lcd.move_to(0,1)
    #display humidity on LCD display 
    lcd.putstr("humdidity:"+str(int(h))+"%")
    sleep(2)