A user may routinely wear or hold more than one computing devices. One of the computing devices may be a head-mounted computing-device configured for augmented reality. The head-mounted computing-device may include a camera. While imaging, the camera can consume power and processing resources that diminish a battery of the head-mounted computing device. To improve a battery life and to enhance a user's privacy, imaging of the camera can be deactivated during periods when the user is not interacting with the head-mounted computing device and activated when the user wishes to interact with the head-mounted computing device. The activation of the camera can be triggered by gestured data collected by a computing device other than the head-mounted computing-device.