How to connect Arduino to ESP8266 for networking function?

To connect an Arduino to an ESP8266 module for networking (such as sending data over Wi-Fi), you typically use UART serial communication. The ESP8266 acts as a Wi-Fi modem or module that the Arduino can control via AT commands or use via libraries like WiFiEsp or even ESP-AT firmware.

Common Components

• Arduino UNO/Nano/MEGA

• ESP8266 module (ESP-01 is common, or NodeMCU/ESP-12 variants)

• Logic level shifter or voltage divider (ESP8266 is 3.3V)

• 3.3V power supply (for ESP8266)

• Wires / breadboard

Wiring ESP8266 to Arduino (ESP-01 Example)

Tip: Use a voltage divider on Arduino TX → ESP RX like:

• 1 kΩ from Arduino TX

• 2 kΩ from TX to GND
  This divides 5V down to ~3.3V safely.

Software Setup (AT Command Method)

1. Upload "bare minimum" sketch to Arduino to release Serial:

2. Use Serial Monitor or software like PuTTY or Arduino Serial Monitor with AT commands to test the module.

3. Example AT commands:

Alternative: Use SoftwareSerial on Arduino

If you want to use Serial Monitor and ESP8266 together:

More Advanced: Use ESP8266 as the Main Controller

• If using NodeMCU or ESP-12, you can program it directly with Arduino IDE using the ESP8266 core.

• This removes the need for an Arduino completely and gives full Wi-Fi + microcontroller in one.

 Summary