In various embodiments, an energy harvesting unit (102, 402, 502, 602, 702, 902) may be configured to convert captured light into current. Logic (104, 404, 504, 604, 704, 904) operably coupled with the energy harvesting unit may be configured to detect a current fluctuation at the energy harvesting unit. The current fluctuation may be caused by a corresponding fluctuation in light captured by the energy harvesting unit. The logic may be further configured to determine that the detected current fluctuation matches a predefined current fluctuation pattern associated with deliberate modulation of light captured by the energy harvesting unit. In some embodiments, the logic may generate appliance control data for controlling one or more appliances (120, 130, 132) based on the matching predefined current fluctuation pattern. In some embodiments, the logic may control light output by one or more light sources (960).