Atmega Microcontroller running at 3.3V and 8MHz 

Arduino Compatible 

Power supply by LiPo battery (3.7V) or USB cable

Solar charge controller with JST connector for Solar Panel up to 2.5W

Battery Monitor

DS3231 Real Time Clock and Temperature sensor, clock backup powered by LiPo battery

8 MBit data flash module (AT45DB)

Micro USB connector

12 Grove connectors connecting Digital, Analog and I2C pins

On/Off switch. With the switch in Off position the solar charge circuit is still active and the RTC clock is still powered.

ICSP programming header

Bee socket for Xbee, GPRSbee or other bee style modules

Same size as Raspberry Pi