In a method for interactive marking by a mobile robot on a vertical surface, a mobile robot that includes a sensor and an actuated marker is displaced across a vertical surface. Features on, in or behind the vertical surface are detected with the sensor. Displacement of the mobile robot and actuation of the actuated marker is controlled in response to the detection of these features.

The present disclosure relates to an electronic device for erasing contents on a writing board. The electronic device comprises a motion detecting unit for detecting movement of the electronic device from resting position which then transmits an activation signal to activate a processing unit and a proximity sensor. The proximity sensor identifies proximity of the electronic device with the writing board. The processing unit receives a signal from the proximity sensor when the electronic device is proximal to the writing board. Further, the processing unit receives selection of colours through user interface on the electronic device for identifying erasable or retainable contents on the writing board. The processing unit transmits a control signal to motion control system to control moveable cleaning surface of the electronic device to perform either pulling or pushing the moveable cleaning surface backward or forward respectively based on the selection of colours.