Design of a Low-Cost Li-Fi Text Transmission Prototype Using an LED and Solar-Panel Receiver, with a Proposed Extension to Files, Images, Audio and Video

Light Fidelity (Li-Fi) uses the intensity of visible light to carry data and is often presented as a complement toWi-Fi in places where radio waves are crowded, restricted or easy to intercept. This paper describes a low-costLi-Fi prototype in which a text file on one laptop is read by a C++ program, sent to an ESP32 that flashes anLED, and received by a solar panel connected to an ESP8266 on a second laptop. The paper explains thesystem architecture, why a solar panel is attractive as a receiver, and its main limitation, which is bandwidth. Itthen proposes a design for extending the system from text to documents, images, audio and video using framing,error detection, retransmission and optional encryption. At this stage, only text transmission has been tested,over a distance of 2 cm on a closed surface, with messages of up to 500 characters sent in one direction only.The extensions to images, audio, video and files, and to two-way communication, are proposed designs thathave not yet been tested, and their feasibility is not yet confirmed. No performance measurements are claimed.The aim is to provide a clear base for later experiments on data rate, range and reliability.