Digital lampshade system and method

A mobile computing device comprising a camera, a transceiver, a processor, and a non-transitory computer-readable medium storing instructions operative, when executed on the processor, to perform functions comprising:

• sending over the transceiver a message causing display of a spatiotemporally varying position-determining light pattern by a selected lamp;
• operating the camera to capture a time-varying position-determining illumination level from the selected lamp;
• based on the captured time-varying illumination level, determining an orientation of the selected lamp relative to the mobile computing device;
• and
• sending over the transceiver a message instructing the selected lamp to modify illumination in a specified direction.

A method comprising:

• in response to a positioning instruction from a mobile computing device, displaying a spatiotemporally varying position-determining light pattern by a lamp;
• after displaying the spatiotemporally varying position-determining light pattern, receiving an illumination instruction from the mobile computing device to modify illumination of the lamp at least in a direction specified in the illumination instruction;
• and
• modifying illumination by the lamp according to the illumination instruction.