The ESP8266 ESP-01 Expansion Board Adapter (ESP-01 / ESP-01S Breakout Shield) is a plug-and-play prototyping adapter designed to simplify connecting the popular ESP8266 ESP-01 Wi-Fi module to 5V microcontroller platforms like Arduino UNO, Mega, and Nano. Featuring an on-board 3.3V LDO low-dropout voltage regulator, integrated bi-directional I/O level-shifting circuitry, and a dedicated 2x4-pin female socket, this breakout board allows safe 5V power and 5V TTL logic interfacing without risking damage to the 3.3V-sensitive ESP8266 chip.

Specifications

• Product Type: ESP8266 ESP-01 / ESP-01S Breadboard & Microcontroller Adapter Shield
• Input Operating Voltage: 4.5V to 5.5V DC (Supports standard 5V USB and Arduino 5V rails)
• Operating Logic Level: 5V / 3.3V Compatible (Integrated 5V-to-3.3V bi-directional level shifter)
• On-Board Voltage Regulator: Low-Dropout (LDO) 3.3V Linear Regulator (Supplies up to 500mA continuous peak current)
• Target Socket: 2x4-Pin (8-Pin) 2.54mm Female Header (Accepts ESP-01 and ESP-01S modules)
• Output / Interface Header: 4-Pin 2.54mm Male Header (VCC, GND, TX, RX)
• Current Consumption: Standby ~80mA; Peak Transmission up to ~250mA–300mA
• Operating Temperature: -20°C to +85°C
• Board Dimensions: Approx. 42mm x 24mm x 11mm
• Mounting Type: Breadboard friendly / Direct jumper wire connection

Features

• Built-in 3.3V Voltage Regulator: Solves the common ESP8266 power issue by stepping down noisy 5V rails into a clean, stable 3.3V supply capable of handling peak Wi-Fi transmission bursts.
• On-Board Logic Level Shifter: Converts incoming 5V UART signals from Arduino/MCU pins down to safe 3.3V levels, protecting ESP-01 RX/TX pins from over-voltage damage.
• Direct 5V Arduino Interfacing: Eliminates the need for external resistor dividers, external power modules, or complex breadboard wiring.
• Dedicated 2x4-Pin Socket: Securely seats standard 8-pin ESP-01 / ESP-01S modules in the correct orientation.
• Breadboard & Jumper Ready: Breaks out essential connections (VCC, GND, TX, RX) to a clean 4-pin single-row 2.54mm header for rapid prototyping.

Common Applications

• Arduino IoT Upgrades: Adding Wi-Fi connectivity and MQTT/HTTP IoT cloud support to Arduino UNO, Mega, Nano, and Leonardo boards.
• Home Automation Projects: Interfacing relays, temperature sensors (DHT11/DHT22), and actuators to smart home platforms (Home Assistant, Blynk, Adafruit IO).
• Wireless Sensor Nodes: Quick prototyping of remote battery/DC-powered Wi-Fi telemetry units.
• Serial-to-Wi-Fi Bridge: Transparent wireless UART bridges for industrial equipment and 3D printer controllers.
• STEM & Educational Labs: Easy, damage-proof ESP8266 classroom experiments without soldering.

Usage Tips

• Module Orientation: Insert the ESP-01 / ESP-01S module into the 2x4 female header with the antenna facing outward (away from the breakout board's main PCB components).
• Arduino Connection:
  • VCC: Connect to Arduino 5V pin.
  • GND: Connect to Arduino GND pin.
  • TX: Connect to Arduino SoftwareSerial RX pin (or Hardware RX).
  • RX: Connect to Arduino SoftwareSerial TX pin (or Hardware TX).
• AT Command Baud Rate: Standard factory ESP-01 firmware defaults to 115200 baud (or 9600 baud for older firmware). When using SoftwareSerial on standard Arduino UNO boards, 9600 baud is recommended for stable data transfer.
• Flashing Firmware: This board is designed as an operational running/interfacing adapter. To re-flash custom ESP-01 firmware/sketches, ensure GPIO0 is pulled to GND during boot, or use a dedicated ESP-01 USB UART programmer.

Datasheet