This device for the blind is meant to produce sound that correlates to the lighting of the atmosphere, so that the blind can share in the mood of the atmosphere. The device is a warm and touching creation, meant to reach out and let those who are deprived of sight share in the experience of the ambient sunlight. The design of the Diapson features a large tuning fork set in a frame of wood. Although it is not shown, I’m guessing it has a photo sensor that translates the intensity of the sunlight to the wavelength of the tuning fork sound. That will mean brighter sun lighting will make higher pitched sounds, which could stand for a cheerful mood, while darker lighting will produce low pitched sounds, which are often associated with gloominess.
Source: YoungDesigner