Implementing Underwater OpticalWireless Communication Using Visble Light LEDs: A Practical Prototype Approach

Abstract

This paper presents the design and experimental demonstration of a prototype underwater optical wireless communication (UOWC) system using visible light in the blue and green spectra. The transmitter employs an Arduino to encode and modulate data via serial communication, driving high- intensity blue and green LEDs through TIP122 transistor circuits. Optical signals propagate through a water channel and are detected by a light-dependent resistor (LDR) module coupled with an LM393 comparator circuit. The analog received signal is digitized using an MCP3208 analog-to-digital converter (ADC), and a Raspberry Pi processes the data stream for decoding and display. A 16x2 LCD screen shows decoded information, while real-time visualization of signal strength and data is displayed on a connected monitor for performance analysis. This study compares the underwater communication capabilities of blue and green LEDs, highlighting that blue wavelengths offer deeper pen- etration in water, whereas green wavelengths provide more stable intensity at shorter distances. The system achieves reliable short- range data transmission with cost-effective and scalable hardware components. The results demonstrate the feasibility of using such a UOWC system for applications in marine research, underwater robotic control, and environmental monitoring, addressing the challenges of underwater signal attenuation and bandwidth limitations with practical circuitry and software solutions.