What is the ESP8266?

The ESP8266, is a cheap WiFi module which you can address using the UART protocol. It’s been featured on Hackaday and other DIY electronics blogs very recently, and lots of DIY electronics tinkers are very excited at the doors this module opens for their projects. The module is:

  • Small Footprint
  • Easy to integrate with (using UART)
  • Takes care of all other overheads for getting WiFi up-and-running (TCP/IP Stack etc…)
  • . . . and, perhaps more importantly than all the other factors, very cheap – it can be purchased from China in a quantity of one for less than £4 !

There are no market equivalents for the DIY community – the XBee has been a popular choice for adding WiFi to DIY projects up until now, but the ESP8266 module is close to one tenth the price making it easily accessible for all types of low cost applications.

The ESP8266 is the name of the chip it’s self manufactured by a company called Espressif, but it is sold in modules manufactured in China which look as seen below,

ESP8266The module can be addressed using a series of AT commands. These are simple commands sent UART at 115200 baud. For example, once the module is wired up, you can send the command

AT+RST will perform a software reset on the device. AT+CWLAPwill displat all of the currently available WiFi networks etc. – simple enough!

How do I set up the ESP8266 Module?

Here is a simple pin-out for the module (the pin numbers are defined in the table and relate to the image):ESP2866 Vector

Pin Number Pin Function/Name Pin Number Pin Function/name
1 RX 5 GPIO2
4 RST 8 TX


Note: Under normal operation Pin 6 (CH_PD) should be tied high (3V3) to ensure correct operation

As such, you can easily wire up the module to an Arduino or just a simple USB to serial converter and start sending AT commands (Remember: RX on the module joins to TX on the connection device and vice versa!).

What are the drawbacks of using this module?

As we’ve seen above, this is shaping up to be a very good value-for-money solution for adding WiFi capabilities to DIY projects, so what are the limitations.

  • The module is rather ‘power thirsty’. The current supplied via USB to an Arduino is barely enough to power this module. Other websites have recommended that you should have easily 1A available, but I have not measured this myself. This makes integrating the module slightly more tricky as a second, separate voltage regulator is required and it also rules out any battery powered projects.
  • It is temperamental – I’ve had a chance to play with this module, and although it works most of the time, all of the sample code I have found provides far from a solid solution – there are plenty of quirks to using it.

Where can I go from now?

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