🌡️ ESP8266 + DHT22 + SSD1306 OLED — Temperature & Humidity Monitor (MicroPython)

🧠 Overview

This project reads temperature and humidity data from a DHT22 sensor and displays it on a 128x64 SSD1306 OLED display using MicroPython on an ESP8266 board.
A minimal, reliable setup for environmental monitoring — ideal for IoT dashboards and smart home systems.

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⚙️ Hardware Setup

Component	ESP8266 Pin	Description
DHT22 Data	GPIO2 (D4)	Temperature & humidity sensor data
OLED SDA	GPIO4 (D2)	I2C data line
OLED SCL	GPIO5 (D1)	I2C clock line
VCC	3.3V	Power supply
GND	GND	Common ground

Connections:

• DHT22 VCC → 3.3V
• DHT22 GND → GND
• DHT22 DATA → GPIO2 (D4)
• OLED SDA → GPIO4 (D2)
• OLED SCL → GPIO5 (D1)

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🧩 Code

from machine import Pin, I2C
import ssd1306
import dht
import utime

# OLED I2C setup
i2c = I2C(sda=Pin(4), scl=Pin(5))  # D1 = SCL, D2 = SDA
display = ssd1306.SSD1306_I2C(128, 64, i2c)

# DHT22 sensor setup
dh = dht.DHT22(Pin(2))  # D4 = GPIO2 (Data)

while True:
    dh.measure()
    tem = dh.temperature()
    hum = dh.humidity()
    utime.sleep_ms(2000)

    # Clear OLED and display readings
    display.fill(0)
    display.text('Temperature:', 0, 0, 1)
    display.text(str(tem), 10, 15, 1)
    display.text('Humidity:', 0, 30, 1)
    display.text(str(hum), 10, 45, 1)
    display.show()

    # Print to serial monitor
    print('Humidity:', hum, 'Temperature:', tem)