RF energy harvested sensory headwear for quadriplegic people

In this work we present engineering optimization of our battery-operated sensory headwear, which uses an inertial measurement unit to detect the head movements and wireless transmits the acquired data. The maneuverability with the head, without the use of hands, makes it ideal for the autonomous use by people with reduced motor skills, such as quadriplegics, for home automation and direct control of actuators. 915MHz radio frequency energy harvester provide additional power to the system, thus increasing the usable time of the headwear and permitting the adoption of a smaller lightweight battery. The harvester, based on commercial chipset, has been conceived to operate with a custom loop antenna integrated on the headwear. In optimal condition, with a fixed RF feeder, an average efficiency as output to input power ratio, around 70% at 5dBm input power level, has been obtained.