Researchers from Delft University of Technology (TU Delft) and Northwestern University have developed a system that enables battery-free devices to keep time despite power interruptions. This could mean that autonomous IoT devices that harvest their energy from the environment wouldn’t need to be fitted with a backup battery anymore.
If you make their energy requirements low enough, IoT devices could power themselves with energy from (a combination of) light, heat or movement in the environment. But this energy supply isn’t quite steady enough, causing brief but frequent losses of power. Without a backup battery, these devices would therefore be rebooting so much they’d essentially be useless.
This is no different in the newly-developed system for batteryless devices, but with a crucial difference: the time and state of the device right before the power outage can quickly be reconstructed. So quickly, in fact, that the loss of power may even go unnoticed.
Research leaders Przemyslaw Pawelczak (TU Delft) and Josiah Hester (Northwestern) disclosed their system at the Architectural Support for Programming Languages and Operating Systems (ASPLOS) 2020 annual meeting. The team presented two papers: one that outlines hardware for the novel timekeeping circuit and another that demonstrates that the circuit can be used to convert battery-powered devices into battery-free devices.