this project supposed to be few hours of weekend entertainment. thanks to cheap chinese products, i spent three weeks instead. anyway, it's stable after few hardware modifications and sketch uploads.

source code does not depend any other library, it can be used as template for similar telemetry applications.

i bricked device while testing AT commands, here is how i revived it: http://www.instructables.com/id/Resurrect-Dead-Esp8266/