Low-cost and compact piezoelectric energy harvesting floor tile for battery-free Bluetooth smart pavement

With the development of the Internet of Things (IoT) technology, a large number of wireless devices are deployed in our surroundings. The power supply issue of these IoT devices has become increasingly noteworthy. On the other hand, the installation and maintenance of a large number of widely distributed sensors are cumbersome. Taking the smart floor for example, in this article, we introduce a battery-free wireless floor tile design based on piezoelectric energy harvesting (PEH). When being excited by a footstep, the piezoelectric floor tile generates an impulsive voltage, which needs to be properly converted to a stable DC form. An energy management circuit is also necessary for properly carrying out the energy buffer-release procedures. Therefore, the circuit part includes components such as an AC to DC rectifier, an under-voltage lockout module, and a voltage regulator. The obtained stable DC voltage is then used to wake and power the Bluetooth node to properly function. Although there were many similar PEH floor tile designs previously built with the same low-cost piezoelectric buzzers, this design is the most compact and inclusive, as a self-powered Bluetooth beacon module. Compared to many energy harvesting floor tile designs, this one has another benefit of a small stroke distance, less than 1 mm, which brings little discomfort to natural walking. Given its motion-powering feature, the power-supply issue, easy deployment, and maintenance issues are all solved. Such smart pavement has the potential to further provide useful information, such as crowdedness, individual tracking, and fall detection, about pedestrians.