Micro-robotics involves the field of miniature robotics dealing with mobile robots that are less than 1 mm in size. Early research in the 1970s by U.S. intelligence agencies explored applications for prisoner rescue and intelligence gathering. Advances in microelectromechanical systems (MEMS) in the 1980s helped enable further development. Due to their small size, microbots could potentially be used in large numbers for applications such as search and rescue in dangerous environments. One challenge is achieving motion with limited power, though microbots may use small batteries or scavenge energy from vibrations or light. Advances in wireless connectivity now allow microbots to coordinate to perform complex tasks.