How to connect ESP8266-01 with Arduino Uno & use AT Commands.


The ESP8266 is a low-cost Wi-Fi chip with full TCP/IP stack and MCU (Micro Controller Unit) capability produced by a Shanghai-based Chinese manufacturer, Espressif Systems.This small module allows microcontrollers to connect to a Wi-Fi network and make simple TCP/IP connections using Hayes-style commands. However, at the time there was almost no English-language documentation on the chip and the commands it accepted.The very low price and the fact that there were very few external components on the module which suggests that it could eventually be very inexpensive in volume, attracted many hackers to explore the module, chip, and the software on it, as well as to translate the Chinese documentation.


  • 32-bit RISC CPU: Tensilica Xtensa LX106 running at 80 MHz*
  • 64 KiB of instruction RAM, 96 KiB of data RAM
  • External QSPI flash – 512 KiB to 4 MiB* (up to 16 MiB is supported)
  • IEEE 802.11 b/g/n Wi-Fi
    Integrated TR switch, balun, LNA, power amplifier and matching network
    WEP or WPA/WPA2 authentication, or open networks
  • 16 GPIO pins
  • SPI, I²C,
  • I²S interfaces with DMA (sharing pins with GPIO)
  • UART on dedicated pins, plus a transmit-only UART can be enabled on GPIO2
    1 10-bit ADC

Pin-Out Diagram


In order to connect the esp8266-01 with the Arduino in the right way. The connections should be made as shown below

  • The Vcc from the ESP8266 should be connected to the 3.3v on the Arduino.
  • The GND should be connected to the GND on the Arduino.
  • The RXD from the ESP8266 should be connected to the RX pin on the Arduino.
  • The TXD from the ESP8266 should be connected to the TX pin on the Arduino.
  • The CH_PD pin should be Connected to the 3.3v on the Arduino.

AT Commands

AT Commands is a list of Commands which helps in communicating between the User and the ESP8266. These Commands can be sent into ESP8266 via Serial Monitor in your Arduino IDE or  Putty. Here a List of AT Commands


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