Upgraded Version ESP-01, all Flash are upgraded to 1M byte. Also support Cloud service remote transmission. This Upgraded Version module are fully supports the previous firmware.
The latest firmware version 1.0.1, the default baud rate of 115200, (AT + CIOBAUD = to change the baud rate), because the old version of the module is 512k bytes of storage space is not enough, so we can not upgrade the 1.0. 1 version, but also support the cloud services!
Serial Wi-Fi Wireless Adapter Module:
A adapter module for ESP-01 Wi-Fi module. 3.3V voltage regulator circuit and onboard level conversion circuit can make 5V microcontroller easy to use with ESP-01 Wi-Fi module.
Also, the item can be used with Arduino UNO R3 or compatible board.
Here is schenmatic: http://img.banggood.com/file/products/20160408023336ESP-01%20Adapter%20module%20Schenmatic.pdf
Working voltage: 4.5~5.5V (On-board 3.3V LDO Regulator)