ESP32 OLED Web Server — Live Sensor Dashboard

#Introduction

Turn an ESP32 into a tiny web server that reports live temperature and humidity — on a web page and on an OLED display.

#Wiring

• DHT11 data → GPIO 4
• OLED SDA → GPIO 21, SCL → GPIO 22
• Both powered from 3V3 and GND

#Steps

1. Install the ESP32 board package (see our Getting Started tutorial).
2. Install libraries: Adafruit SSD1306, Adafruit GFX, DHT sensor library.
3. Flash the sketch below, editing WIFI_SSID / WIFI_PASS.
4. Open the IP shown on the OLED in your browser.

#How it works

The ESP32 hosts a minimal HTTP server. Every request re-reads the DHT11 and renders an HTML page; the same reading is pushed to the OLED over I2C.

#Troubleshooting

• OLED blank → check I2C address (0x3C vs 0x3D) and wiring.
• DHT reads 0 → most modules need the data pin pulled up (onboard on breakouts).