Mobile robots with sensors have useful applications but moving them requires significant energy. Batteries have limited lifespans, constraining functionality.

University of Washington researchers created the solar-powered MilliMobile - a small robot that travels 10 meters per hour solely using ambient light. It can carry sensors and cameras nearly triple its weight across various surfaces.

Inspired by intermittent computing, the team broke movement into discrete steps requiring tiny energy bursts. By minimizing size and mass, a little energy rotates the wheels. This incremental motion resembles animal movement.

Tests spanned indoor and outdoor environments from farms to offices. Even in low light, the MilliMobile still moves, albeit slower. But continuous operation, however gradual, enables new possibilities.

Swarms of MilliMobiles could reach areas single fixed sensors cannot, collecting spatial data to map environments. Potential applications range from agricultural monitoring to finding factory equipment faults.

The robot carries light, temperature and humidity sensors, plus Bluetooth. Future plans include more sensors and coordination between swarms for greater insights.

Battery limitations have confined small mobile robots. The MilliMobile's solar-powered perpetual operation lifts these constraints, allowing new data gathering roles through tireless incremental motion.

While speed is limited, this research displays the possibilities of purpose-built miniaturized robots leveraging environmental energy. Their unique mobility could unlock environmental mapping at high resolutions.