Energy harvesting reference design, 'industry's most efficient'

The wireless energy harvesting system is based on SiLabs' Si10xx wireless microcontroller family, which has been designed to perform control and wireless interface functions at ultra low power levels. The company describes the mcu range as the 'most power efficient' of its kind. The reference design consists of three components: firstly, a solar powered wireless sensor node that measures temperature, light level and charge level, using an Si10xx wireless mcu to control the sensor system and transmit data wirelessly and a thin film battery to store harvested energy. Secondly, a wireless USB adapter connects the wireless sensor node to a pc for displaying sensor data. The adapter features SiLabs' Si4431 EZRadioPRO transceiver with an mcu running USB-HID class software and EZMac wireless software stack. Finally, a wireless sensor network GUI displays data from up to four sensor nodes. The thin film battery used in the energy harvesting reference design has a capacity of 0.7mAh. According to SiLabs, in direct sunlight, the battery can be recharged fully in two hours, while in sleep mode, the wireless sensor node will retain a charge for 7000 hours. If the wireless system is transmitting continuously, it is designed to operate non stop for about three hours and constantly recharges itself at an appropriate level to keep the thin film battery from completely discharging. "As part of our global commitment to green technology, Silicon Labs has advanced the use of energy harvesting technology to free wireless networking systems from the cost, inconvenience and negative environmental impact of conventional batteries," said Mark Thompson, vice president of Silicon Labs' Embedded Mixed Signal products. "By combining ultra low power wireless mcu technology with a state of the art energy harvesting system, Silicon Labs has delivered the industry's most energy efficient, self sustaining wireless networking solution." The reference design is available from today.