NodeMCU with ESP8266 Wi-Fi SoC
This implementation of Espressif’s system-on-chip makes for a fantastic platform for wifi connected/controlled devices because of its ability to run off a 5v through micro-USB.
The development board is not much larger than the usb wall adapter that would be used for power.
With four conveniently placed mounting holes.
Silicon Lab’s CP2102 takes care of programming the SoC, a standard usb-to-uart bridge.