Robots are becoming security guards. 'Once it gets arms ... it'll replace all of us'

William Santana Li imagines a future where robots will keep Americans safe. Communities, he dreams, will take security into their own hands by investing in wheeled machines that patrol streets, sidewalks and schools -- instantly alerting residents via a mobile app of intruders or criminal behavior. "What if we could crowd-source security?" said Li, co-founder and chief executive of a robotics company, Knightscope, that hopes to eventually do just that. His question is like many posed by Silicon Valley entrepreneurs seeking to modernize, privatize and monetize services once entrusted to the government -- and it's one that has intrigued venture capitalists who have pumped 14 million into his start-up. Already, Knightscope robots are edging into the private security industry, patrolling parking lots, a shopping center and corporate campuses in California.