Miniature Pneumatically Driven Electromagnetic Energy Generator Shoe Insert

Applications

Portable and wearable electronics including smart watches, health monitors, emergency locators and radio frequency identification tags
Problem Addressed

Wearable and portable electronics devices are becoming increasingly popular in daily life. Devices such as smart watches, health monitors, radio frequency identification tags and emergency locators are generally battery powered, resulting in limited lifetimes. Currently, a cost-effective method for harvesting waste energy for human motion that provides adequate energy for electronic devices does not exist. One alternative to conventional batteries is to harvest human waste energy to power wearable and portable electronics devices. Human motion is one of the most ubiquitous forms of waste energy.

Technology

The invention provides a method for extracting energy from foot strikes using air pumps and miniature wind turbines. Because foot strike energy is in a low frequency regime and deformation of the shoe heel is quite limited, the pump and turbine are used to compress the air and convert the human energy to electrical energy. The power generated from walking at 1 Hz is approximately 6 mW. Design optimizations are predicted to lead to order-of-magnitude increases in power output with a theoretical power generation of 150 mW. Using the device while running would also increase the power output due to the increased foot strike rate. The device is both small and lightweight, thus no comfort is lost by integrating the invention into running or walking shoes.

Advantages

On the order of 100 mW power production predicted
Simple structure increases reliability and longevity
No loss of comfort from integration of device into walking or running shoes
Light-weight and small