Overview
- Researchers at the University of Pennsylvania and the University of Michigan integrated computation, sensors, photovoltaics and propulsion on a 200×300×50 micrometer CMOS chip smaller than a grain of salt.
- The robots swim via electrokinetic flow by moving ions in surrounding fluid, reaching roughly one body length per second with no moving parts and operating for months under illumination.
- Microscopic solar cells supply about 75 nanowatts, enabled by ultra-low-voltage circuits that cut computer power by more than 1,000× and a condensed instruction set that fits in tiny memory.
- Light pulses both power and program the devices using unique addresses, and on-chip temperature sensors (~±0.33°C) support behaviors like heat-seeking and motion-encoded data reporting captured by a microscope camera.
- Results appear in Science Robotics and PNAS, with reported unit cost near one cent and prospective uses in medicine and microscale manufacturing described as future directions.