Scientists build robots smaller than a grain of salt that can think

Researchers at the University of Pennsylvania and the University of Michigan report fully programmable, light-powered robots about 200×300×50 micrometers in size that can swim, sense temperature, follow simple programs, and operate for months.

Researchers at the University of Pennsylvania and the University of Michigan report the smallest fully programmable autonomous robots to date. Each machine measures about 200 by 300 by 50 micrometers, smaller than a grain of salt, and costs roughly one penny to produce. The light-powered robots can swim through liquid, sense local temperature, follow programmed paths, and operate for months. The work was reported in Science Robotics and Proceedings of the National Academy of Sciences. Key facts: - Size and cost: each robot is roughly 200×300×50 micrometers and costs about one penny to make. - On-board computing: the team placed a processor, memory, and sensors on each sub-millimeter device so the robots can make simple decisions independently. - Propulsion method: electrodes produce an electrical field that moves ions and the surrounding fluid, allowing swimming without moving parts and coordination in groups, at speeds up to about one body length per second. - Sensing and communication: robots include temperature sensors sensitive to about one third of a degree Celsius and relay measurements by encoding values in small motion patterns that are read by microscope camera; light both powers and programs each robot, and each unit has a unique address. - Power and durability: tiny solar panels provide on-board power (about 75 nanowatts), specialized low-power circuits reduce energy needs, and the absence of moving parts helps the devices survive repeated transfers and run for extended periods. - Teams and publication: the work was led by Marc Miskin at Penn and David Blaauw at the University of Michigan and was supported by agencies and foundations including the National Science Foundation, AFOSR, the Army Research Office, and private foundations. Summary: The researchers describe this work as opening a new scale for programmable robots and note potential uses such as monitoring individual cells or assisting in micro-scale manufacturing. Future development described by the teams includes adding more advanced programs, extra sensors, higher speeds, and adaptations for different environments. Undetermined at this time.