【ESP8266】 Serial WIFI Module ESP8266 Wireless Transceiver Module 【Compatible】 This module requires a 3.3 volt supply for VCC, and 3.3V logic. It is not 5V tolant,Connect RX or TX on 5V Arduino will destroy this module. 【Design compact】 Model: ESP8266;ISM 2.4GHz;PA +25dBm;802.11b/g/n 【Easy operation】 The 3.3V supply on the Uno has inadequate current capabilit to power this module. 【Interface】 You must provide a separate,higher 3.3V supply(about 300mA or better).You must use a logic level converter, or a 3.3V