Scientists Crammed a Computer Into a Robot the Size of a Grain of Salt
Researchers from the University of Pennsylvania and University of Michigan have created autonomous robots just 200 by 300 by 50 micrometers in size—roughly the size of a grain of salt. These robots can swim in liquid, sense temperature changes, make basic decisions, and operate for months on minimal power. Their design abandons traditional moving parts; instead, they use electric fields to move charged particles in liquid, dragging water molecules along for propulsion. Each one contains a tiny computer, sensors, and memory, forming a complete system at a new, unprecedented scale, all for about a penny per unit. Powered by LED light and solar panels that deliver only 75 nanowatts, the robots use ultra-efficient circuits and highly condensed software. They sense temperature with high precision and communicate results by encoding data in the movement patterns—observable via microscope. Programmable through light pulses and with unique addresses for each unit, the robots can operate independently or in coordinated swarms. This breakthrough demonstrates a platform for future research, with potential applications ranging from cellular monitoring to complex programmable behavior in microscopic environments.
