ESP-01S ESP8266 Wi-Fi Module

The ESP-01S is the smallest ESP8266 module: 24.8 × 14.3 mm with 1 MB flash and 8 pins. Out of the box it understands AT commands, so an Arduino Uno can use it as a serial Wi-Fi modem. You can also flash your own Arduino sketch onto it and use its two GPIOs to drive a relay or read a sensor — the basis of countless Wi-Fi relay and DHT boards.

Key features

• ESP8266 Wi-Fi in a 24.8 × 14.3 mm module
• 1 MB flash, ships with AT firmware
• Works as a Wi-Fi modem for Arduino or as a stand-alone controller
• Improved S version with pull-ups and status LED on GPIO2

Specifications

What's in the box

• 1 × ESP-01S module

Ideal for

• Adding Wi-Fi to Arduino Uno / Nano
• ESP-01 relay and sensor shields
• Minimal Wi-Fi switches

Good to know

• Power from 3.3 V only — 5 V will destroy the module.
• Use a USB-to-ESP01 programmer adapter to flash your own firmware.