Overview
The ESP-01 is an ultra-compact, low-cost ESP8266-based Wi-Fi module that provides an easy and affordable way to connect your microcontroller projects to the internet. Despite its small form factor, this module features an onboard antenna and a self-contained SOC (System on a Chip) with an integrated TCP/IP protocol stack.
The ESP-01 can operate in two primary ways:
As a Wi-Fi Adapter: Hook it up to an existing microcontroller (like an Arduino) using standard AT commands via Serial UART.
As a Standalone Microcontroller: Flash your own firmware directly onto its onboard flash memory to run independent programs, utilizing its available GPIO pins.
Key Features
High Integration: Combines an antenna, power management, and RF front-end into a tiny, space-saving footprint.
Dual Operation Modes: Works as a slave device managed by AT commands, or as an independent, standalone Wi-Fi controller.
Low Power Consumption: Features advanced power-save modes (Deep Sleep) suitable for battery-operated IoT applications.
Standard 2x4 Pin Header: Uses a standard 2.54mm pitch 8-pin interface for easy connections (though breadboard-unfriendly without an adapter).
Massive Community Support: Highly compatible with the Arduino IDE and supported by an extensive ecosystem of open-source libraries.
Technical Specifications
Feature | Specification |
Wi-Fi Protocol | 802.11 b/g/n |
Frequency Range | 2.4 GHz – 2.5 GHz (2400M–2483.5M) |
Processor | Tensilica L106 32-bit RISC MCU |
Operating Voltage | 3.3V Only (5V will damage the module) |
Operating Current | Average: ~80mA, Peak: ~300mA (Requires a stable power source) |
Flash Memory | 1 MB (typically, though older variants may have 512 KB) |
Security | WPA / WPA2 / WEP / TKIP / AES |
Network Protocols | IPv4, TCP / UDP / HTTP / FTP |
Serial Baud Rate | 115200 bps (default) |
Antenna Type | Onboard PCB trace antenna |
Pinout Configuration
The ESP-01 module features 8 pins configured in a 2x4 header layout:
GND: Ground (0V).
TX: Transmit Data pin (connected to RX of microcontroller, 3.3V logic).
GPIO2: General Purpose Input/Output pin 2.
CH_PD (EN): Chip Enable/Power Down. Must be pulled HIGH (3.3V) to enable the chip.
GPIO0: General Purpose Input/Output pin 0. Must be pulled LOW to put the module into flash/programming mode.
RST: External Reset pin. Active LOW.
RX: Receive Data pin (connected to TX of microcontroller, 3.3V logic).
VCC: Power supply pin. Must be 3.3V.
Important Usage Notes (Precautions)
⚠️ Voltage Warning: The ESP-01 operates strictly on 3.3V. Connecting the VCC pin to 5V, or connecting standard 5V Arduino RX/TX lines directly to the ESP-01 without a logic level converter, can permanently damage the module.
🔌 Current Demands: The module can pull sharp spikes of current up to 300mA during Wi-Fi transmission. The 3.3V pin on a standard Arduino Uno is often insufficient. It is highly recommended to use a dedicated 3.3V voltage regulator or an ESP-01 Breadboard Adapter with a built-in regulator.
Target Applications
Home Automation: Smart plugs, smart lighting, and remote appliance control.
Wireless Sensor Networks: Logging data from temperature, humidity, or motion sensors straight to the cloud.
IoT Prototyping: Connecting legacy electronics or industrial equipment to a web server.
Web Servers & Clients: Hosting a local webpage to control hardware via a phone browser, or fetching online data (like weather or time updates).
Package Includes
1 x ESP-01 ESP8266 Wi-Fi Module.