A low-cost surveillance and information system for museum using visible light communication

This paper designed and implemented a low-cost surveillance and information system for museums with two new coding schemes using visible light communication. For security, we use a key in place of the clock in the Manchester coding. For the enhanced data transfer, we use the unbalanced time duration for data one and zero. The prototype system was built with two low-cost microcontrollers, an LED, and linear light sensors. With 1-m distance in a dark environment, the maximum data transfer rate was roughly 1.93 kbits/s with a 10\Phi white LED. Under the dark-to-modest ambient brightness of up to 120 lux, the white LEDs were performed well in terms of the transmission distance, compared with LEDs with different colors. The experiments with flashlights reveal that our system can easily detect the prohibited use of flashlight. Experiments with the mobile phones' flashlight also revealed that photographing with the flashlight would have a worse impact on arts than the continuous illumination. We also measured the distance between arts to avoid inevitable interference between illumination sources in neighbor.