Power efficiency is a requirement for long term operation at a remote site. Power management is done both by hardware and firmware.
In hardware, every augmented sensor is equipped with rechargeable batteries. They can be recharged by mains electrical power or through USB connection to a PC.
To ensure that the wireless sensor network can autonomously operate for months, hence without requiring the replacement or change of batteries, it is essential that power management is also implemented in the firmware. Thus, the sensors are programmed to be in ultra low power consumption mode when they are idle. Also, radio communication, the most energy consuming operation, is kept to minimum by aggregating as many measurements as possible in the sensor's embedded memory card.