In this paper, an easy-to-use measurement device for illumination distribution is developed. The device consists of a sensor array module, a control module, and a PC interface. The sensor array module incorporates CIE 1931 color sensors and the ARM-based 96 MHz microcontroller in the control module for measurement and data processing. The sensor array module contains 64 color sensors arranged in a 16 × 4 array. The sensitivity of the sensor array module can be adjusted depending on the illumination level to be measured. The measurement data and control signals are exchanged via USB 2.0 standard. To demonstrate the performance of the device, the illumination distribution is measured for colors of red, green, and blue and is graphically shown. The device can be used for measurement of the illumination distribution, design and adjustment of LED illumination.

A visible light communication to transmit high quality video and audio signal was demonstrated by using illumination LEDs. In the transmitter, by using ultra high speed comparator, the analog video signal was modulated to 15 MHz pulse width modulation (PWM) signal. The analog audio signal was analog-to-digital converted with 192 KHz sampling rate, 24 bits resolution. The video and audio signals are transmitted using the illumination LED transmitter. In the receiver, a photodiode senses the optical signals transmitted from the LED transmitter and the received electrical signal is amplified. And then, the digital signals are recovered. The digital signals are converted into analog signal. Due to the digital transmission based on visible light from the illumination LED, the high-quality video and audio signal transmission is performed.

We report 1 Mb/s data transmission over PWM dimming control signal for a visible light communication (VLC) system based on a simulation. The simulation program is developed using MATLAB and Simulink. In this simulation, the data stream of non-return-to-zero on-off keying (NRZ-OOK) is transmitted together with a dimming signal for brightness control, which has the form of pulse width modulation (PWM). The PWM frame rate is set to 1 kHz to avoid flickering in human eyes. The data rate is set to 20 kb/s and 1 Mb/s. We report eye diagrams of NRZ data streams for 20kb/s and 1Mb/s.