Visible light communications - Research - Jimmy C. Chau - Boston University
Visible light communications
The Smart Lighting Engineering Research Center aims to integrate visible light communication (VLC) capabilities into future LED lighting systems. Ideally, this integration will ensure the availability of network connectivity wherever artificial lighting is installed, enabling the widespread use of networked devices that form "smart rooms".
Toward this objective, I have developed a range of lighting and visible light communication systems.
Scalabe MIMO VLC receiver architectures for mobile use
In my current research, I am investigating the use of special-purpose cameras as receivers for VLC signals. Such a VLC receiver would be able to track and receive from multiple transmitters simultaneously, enabling the receiver to combine many lower-speed transmissions into one high-speed link with the combined capacity of each transmission.
Lighting Arrays as Modular Parts (LAMP) is a networked, color-controllable luminaire prototype.
SL1 and SL2
The "Smart Lighting One" (SL1) kit and its lower-cost successor, the SL2, provide the capabilities for computers with USB ports to communicate over a visible light communication (VLC) link. Created in 2009 and 2010 respectively, the SL1 and SL2 kits have been manufactured and distributed to industry and research partners as both demonstration units and development platforms.
The SL1 kit contains two VLC transceivers, each with their own power supply and data cable for the USB interface; demonstration software and documentation is included in the kit. Each transmitter produces 400 lumens of white light, suitable for lighting a small part of a room. At a two meter distance, the SL1 transceivers have demonstrated the capability to form a 1Mb/s optical link.
The SL2 reduces costs with a simpler LED driver for the transmitter and by using off-the-shelf photodetector modules as part of the receiver. The new current-mirror-based LED driver is compatible with a variety of LEDs, including white LEDs, monochromatic color LEDs, and infrared LEDs. The SL2's receiver is also compatible with a variety of off-the-shelf photodetector modules. Together, they are able to form links supporting up to 4MHz on-off-keying signals. However, due to AC-coupling in the receiver, the SL2 is unable to reliably carry uncoded serial data.