Casio exhibited their Visible Light Communication system at the Consumer Electronic Show (CES) in Las Vegas this week.
I was not at CES so this post is based on a number of reports I have obtained from various sources about their VLC prototype. Also, here is the link to their official press release about the prototype.
Casio use the smart phone display to transmit the data which can be captured on the smart phone’s camera. A VLC App is required on both the transmitting and the receiving smart phone devices. The transmitting device sends the data by displaying a large spot on the screen which rapidly changes colour. The receiving device’s camera is pointed towards the spot on the display and the images are processed to decode the information. I am told that it takes a few seconds to transmit the equivalent of a short message or tweet.
According to Nobuo Iizuka, a research manager at Casio, the spots need to be 1cm in diameter for every meter of transmission distance. This means that a small spot could be added to TV commercial adverts, or to electronic billboards to transmit a URL. Several transmit devices can be used simultaneously if they are all within the view of the camera. I did hear about a few operational issues in practice with sunlight, reflections and shadows.
Clearly there are a number of applications that could use this. I do know that my Edinburgh University colleagues have also developed low data rate VLC receivers using standard smart phones. What Casio have done additionally is to use the smart phone display as the transmitter.
I think the important point to note is; if useful applications can be developed based on low data rate VLC systems with unmodified smart phones, then logically even more useful applications can be created if the smart phone has its sensors adapted for much higher data rates.