Research On Indoor LED Visible Light Communication Based On STM32

With the development of all-optical communication technology and people’s growing demands for broadband mobile communications, the wireless optical communication technology has been a great concern. It has a large information capacity, low cost, flexibility and easy maintenance. It is a broadband wireless access technology that combines wireless communications technology and optical communication technology. Light signals work as the information carrier and atmosphere works as the information transmission medium to transmit light signals. Since the20th century, the semiconductor lighting technology has developed very rapidly. It is known as the "green light". LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. It works as the light source of the optical communication system because of its short response time, high-speed light-emitting response and high-speed modulation. German physicist Harald Haas and his team in University of Edinburgh invented a patented using the LED light technology. The invisible network signal dependent on a small lamp becomes "visible" network signal. Visible light communications signals work by switching bulbs on and off within nanoseconds, which is too quickly to be noticed by human eyes.In this paper, an indoor LED visible light communication system is designed using LED as a communication source. Source transmitted through serial communication to the MCU where it is modulated. The modulated electrical signals work by switching bulbs on and off within nanoseconds, which is too quickly to be noticed by the human eye. The optical signal projected on the photodetector through free space, the Fresnel lens and the filter. The photodetector converts the received optical signal into an electrical signal. After equalization, judgments and decoding process to restore the information transmitted to the computer on the receiving end. After reduction and decoding process, the electrical signal is transferred to the computer. This paper analyzes the principle of the indoor LED visible light communication system, designs the overall program and complete serial data communication section, power amplification section, the driving circuit module and the receiver section.