Itead Sonoff Basic

Property	Value
Manufacturer	Itead Studio
Product page	https://www.itead.cc/sonoff-wifi-wireless-switch.html
Wiki page	https://www.itead.cc/wiki/Sonoff
Build flag	ITEAD_SONOFF_BASIC

Introduction

The original Sonoff (now renamed Sonoff Basic) has an ESP8266 on board with a 8Mbit flash memory chip, a mains to 3V3 transformer and a relay (GPIO12). It also features a button (GPIO0), an LED (GPIO13) and an unpopulated header you can use to reprogram it.

GPIO	Usage
0	Main button
1	TX
2	(R2) Available in header
3	RX
12	Relay
13	LED (inverted logic)
14	(R1) Available in header

Flashing

The unpopulated header in the Sonoff has all the required pins. My board has a 5 pins header in-line with the button. They are (from the button outwards) 3V3, RX, TX, GND and GPIO14 (or GPIO2).

The last one is not necessary. The button is connected to GPIO0 on the ESP8266 / ESP8285 chip, so to enter flash mode you have to hold the button pressed while powering on the board, then you can release it again.

Issues

The original Sonoff has some connectivity issues. This is probably due to the antenna placement close to live lines. It works fine if it's near the AP, otherwise, it's often reported to lose connectivity.