Connecting networks of toys and smartphones with visible light communication

Light emitting diodes are low-cost and energy- efficient. They are replacing incandescent bulbs as the primary source of illumination in residential and public environments. The brightness of LEDs can be modulated at a high rate, which enables the combination of illumination and wireless communication, imperceptible to humans. Such systems using LEDs as transceivers are called visible light communication systems. LEDs have also been extensively used in consumer electronics such as toys and smartphones, but primarily for reasons other than communication. We show various use cases of devices connected with VLC. Since LEDs can also be used as light receivers in VLC systems, adding microcontrollers to devices (if not already embedded) enables low-cost implementation of a wireless communication interface with VLC. This article reports on experience with several prototypes of practical VLC systems.