Audio Transmission Using Light Fidelity

Abstract

Li-Fi(LightFidelity)technologyisaninnovativewirelesscommunicationsys- tem that utilizes visible light for data transmission, offering an alternative to traditional radio frequency-based methods like Wi-Fi.In this approach, audio signals are transmitted through modulated LED light and received by a pho- todiode, whichconvertsthe lightbackintoaudio signals. Thesystemallows forreal-time,high-speed audiotransmissionwithminimalinterference,aslightwavesdonotoverlap withradio signals,makingitidealforenvironmentswhere radio frequencies are either restricted or congested.The implementation in- volves key components such as an LED transmitter, photodiode receiver, and circuitsformodulationanddemodulation. Li-Fioffershigh datasecurity, since light cannot pass through walls, reducing the risk of eavesdropping.Despite challenges such as line-of-sight dependency and susceptibility to ambient light interference, Li-Fi shows immense potential for secure, fast, and interference- free audio transmission, paving the way for advanced communication systems in both public and private sectors.

Introduction

Introduction

• Wireless communication is facing RF spectrum congestion due to the rise in connected devices.

• Li-Fi (Light Fidelity) offers an alternative, using visible light instead of radio waves to transmit data.

• Operates via modulated LED light and is:

  • Faster (10,000x larger bandwidth than RF)

  • More secure (light doesn’t penetrate walls)

  • Interference-free, making it ideal for hospitals, aircraft, and military use.

2. Application in Audio Transmission

• Li-Fi can transmit audio signals by modulating light intensity via LEDs.

• A photodetector receives the modulated light and converts it back to an electrical audio signal.

• Offers clear sound transmission in RF-sensitive or interference-prone environments.

3. Literature Review Highlights

• VLC (Visible Light Communication) allows high-speed, short-range data transmission using LEDs.

• Applications include indoor navigation, vehicular communication, and secure data transfer.

• Research has improved receiver sensitivity, modulation techniques, and energy efficiency.

• Real-time audio streaming using VLC shows low-latency, high-fidelity performance.

4. Proposed Methodology

• Audio source (like a phone) sends signal through an AUX cable.

• Signal is used to modulate an LED's brightness, converting it to a light signal.

• A solar panel (photodetector) receives light and reconverts it to an electrical signal.

• Signal is amplified and played through a speaker.

5. System Architecture

Key Components:

• LED transmitter

• Photodetector (solar panel)

• Amplification circuit (TPA3110 Class D amplifier)

• Speaker

Important Features:

• LED modulation enables real-time transmission.

• Amplifier boosts the weak signal from the receiver to ensure clear audio playback.

• The solar panel was chosen over a photodiode due to its larger surface area, aiding signal capture.

6. Hardware Implementation

• Audio Transmission via AUX cable.

• LED modulates brightness based on the audio.

• Solar panel detects light intensity and converts it to audio signal.

• TPA3110 amplifier boosts the signal for speaker output.

• 15W speaker ensures clear and audible output.

7. Results

• Successful real-time audio transmission using Li-Fi.

• Stable connection and low delay confirmed feasibility.

• Amplifier significantly improved sound quality—without it, audio was barely audible.

• Demonstrated the practicality of Li-Fi for audio in enclosed or RF-restricted spaces.

Conclusion

The audio transmission using LiFi successfully demonstrated the feasibility of transmitting an audio signal, fromasmartphonethroughanauxcablewithapeakoutputvoltageof0.447V,whichwasthenusedtomodulateanLED.Thesolarpanel,actingasaphotodetector,capturedtheweakopticalsignal,whichwasthenamplified by the TP3110 IC to drive a 15 W speaker, reproducing the audio with minimal distortion.LiFi’s directional nature ensures secure one-to-one data transfer, minimizing interference risks compared to RF-based systems. The setup highlights LiFi’s potential for short-range, interference-free communication, particularly in EMI- sensitiveenvironments. Furtherimprovementsin LEDmodulationand photodetector sensitivitycouldenhance performance.This experiment validates LiFi’s viability as a high-bandwidth, secure alternative for localized wireless audio and data transmission.

References

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Copyright

Copyright © 2025 Anandhu M T, Evelina D, Ilyas Mubarack, Zaahil P Rawther, Mohitha Thomas, Reenu George. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.