Harvesting electricity from vibration, ambient light, and thermal energy sources represent a sizable technical challenge — all three are low-voltage and relatively intermittent. MIT doctoral student Saurav Bandyopadhyay rose to this challenge by helping create a single power-regulating chip that can harvest and combine all three into a single output. He explains that "[at] one particular instant, energy is extracted from one source by our chip, but the energy from other sources is stored in capacitors" where it can be used later. The chip uses a high-frequency switching mechanism to quickly adjust to any changes in input power, resulting in a clean and steady power output without the use of a single battery. This kind of battery-free design enables equipment that was previously impractical to make, like biomedical devices and remote environmental sensors.