Technical University Iași - Faculty of Automatic Control and Computer Science
Microprocessor Systems
Laboratory No.8+
  • L8+.1 Title

    • SMpixel - LiFi protocol communications


  • L8+.2 General presentation, purpose

    • The laboratory work aims to introduce the LiFi universe usable for communications with IoT equipment, represented by the company pureLiFi. Using UART-type communications between RPi and Pico, a transmitter module and a receiver module are presented which allow data transfer represented by light fluxes emitted by a high-power LED. The transmitter is connected to a Web/Linux/RPi server and the receiver to SMpixel/L7+.
    Data format represented by light as well as the accuracy of the transmission are analyzed to allow activation through light of SMpixel modules.
    At the end of the laboratory you will have relevant information about the possibilities of developing a new mode of information transmission using visible light as a carrier medium.


    Research paper1
    Research paper2

  • L8+.3 Resources


    • Hardware: LiFi transmitter, LiFi receiver, SMpixel


    Software: MicroPython

  • L8.4 Example programs

    • 1. Local SMpixel software for LiFi/300bps
    2. RPi software for SMpixel test/300bps
    3. Web page SMpixel LiFi commander/300bps
    4. Character transmission at 300 bps



  • L8+.5 How to conduct/track laboratory

    • The transmission interface is made of a 3W LED interconnected to RPi through a power module composed of 2 transistors represented in the schematic below.



    The reception is performed by using an optical sensor of solar generator type provided with an amplification module and a comparator represented in the following figure.



    The reception module can be interconnected with an RS232/USB converter and using a terminal program like Teraterm the received characters can be viewed, possibly corrections can be made by the potentiometer at the comparator input to compensate the ambient light level.



  • L8+.6 Proposed problems
    • 1. Create a Python script that will allow determining the maximum transmission speed of characters using the 2 LiFi modules.
    2. Create a Python application that will repeatedly emit the character "U" and view with the oscilloscope the edges of the received signals.
    3. Create a LiFi interface that will use Manchester encoding for data.
    4. Create an SMpixel extension with simple LiFi interface;
    5. Analyze data encoding modes for LiFi transmissions and implement on SMpixel a robust solution.

  • L8+.7 The experiment can be extended to:


    • - Implementation of IoT systems with optical interface;
    - Development of automotive applications with possibilities of communication through headlight beams;
    - Development of computer networks in educational spaces and hospitals without the presence of electromagnetic radiation of WiFi type.
    - Development of communication networks with maximum security for military applications
    - Implementation of underwater communication systems.



  • L8+.8 Additional information

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