SmartStep 2.0 - A completely wireless, versatile insole monitoring system

Insole based wearable sensors are becoming popular in applications such as gait and physical activity monitoring, energy expenditure estimation, in providing biofeedback, fall risk and others. In the existing systems, the insole needs to be taken out of the shoe to recharge the battery, which is not a convenient task. The existing systems are application specific and can be used for a limited purpose. However, the desired system functionality for the shoe based wearable systems depends on factors such as the targeted age group of the individuals and laboratory set up vs free living conditions. We attempt to fill these gaps in this work, as we present the recent advancements in SmartStep monitors - SmartStep 2.0, making it a completely wireless, versatile gait data acquisition device. We discuss the implementation of the seamless wireless charging feature to resolve the battery charging problems, along with the implementation of the base station for charging purposes. In making the SmartStep 2.0 a versatile insole monitor, we discuss the implementation of the Wireless Firmware Upgrade (WFD) feature, which allows the same insole system to be used in different application scenarios. Two example application scenarios for wireless gait data acquisition are discussed, along with the power consumption figures in different modes. Results suggest that the SmartStep 2.0 can potentially be used in the ambulatory monitoring of physical activity and gait in laboratory as well as in free living conditions.