PIXHELL: When Pixels Learn to Scream

TL;DR

This paper introduces a novel method to generate sound by exploiting vibrational noise from LCDs during pixel transitions, enabling new applications in communication and HCI.

Contribution

The paper demonstrates how LCDs can be used as sound sources through pixel modulation, a previously unexplored use of display hardware.

Findings

LCDs produce audible noise during rapid pixel changes.

The system can generate recognizable sound signals.

Potential applications include covert channels and secure communication.

Abstract

This paper presents a technique for generating sound by leveraging the electrical properties of liquid crystal displays (LCDs). The phenomenon occurs due to vibrational noise produced by capacitors within the LCD panel during rapid pixel state transitions. By modulating these transitions through specially crafted bitmap patterns projected onto the screen, we demonstrate how weak yet audible acoustic signals can be generated directly from the display. We designed, implemented, evaluated, and tested a system that repurposes the LCD as a sound-emitting device. Potential applications for this technique include low-power auditory feedback systems, short-range device communication, air-gap covert channels, secure auditory signaling, and innovative approaches to human-computer interaction.