From robot workers to drone deliveries, Amazon is known for using innovative and futuristic technologies. But the latest patent suggests that the firm wants to take things further, and use technology to track its workers. The patent reveals designs for ultrasonic wristbands that could be used to monitor workers' performance. The latest patent suggests that Amazon wants to take things further, and use technology to track its workers. The patent reveals designs for ultrasonic wristbands that could be used to monitor workers' performance The patent describes'ultrasonic tracking of a worker's hands' that would be used to'monitor performance of assigned tasks.'