Methods for detecting an alignment of a robot with a virtual line, including: transmitting, with at least one transmitter of the robot, a first signal; receiving, with a first receiver and a second receiver of a device, the first signal; detecting, with the device, that the robot is aligned with the virtual line when the first receiver and the second receiver of the device simultaneously receive the first signal; transmitting, with at least one transmitter of the device, a second signal indicating that the robot is aligned with the virtual line; receiving, with at least one receiver of the robot, the second signal; actuating, with a processor of the robot, the robot to execute a movement upon receiving the second signal; and marking, with the processor of the robot, the location of the device in a map of an environment of the robot.