# Experimental Demonstration of Single-Channel EEG Signal Using 32 x 32 Pixel OLED Screen and Camera
## 1 Introduction  
Electroencephalography (EEG), discovered in 1924 by [PERSON], is a non-invasive procedure to diagnose brain diseases. The conventional EEG recording techniques are deployed by using several scalp electrodes, which involves a long preparation time and are tedious. However, the growth of wireless technology has led to wearable EEG headsets that are used for brain monitoring for specific applications, such as Nuerosky, Imec, emotive, etc. [1]. Furthermore, the radiofrequency (RF)-based technology, such as Bluetooth and ZigBee, are used in many EEG machines for data communication, but the RF technologies suffer from lack of frequency spectrum, eavesdropping, and electromagnetic interference [2; 3; 4; 5]. VLC can be used for both for lighting and data communication hence, the useof LED lights, existing everywhere, for data communication is a cost-effective alternative to RF technology, specifically in hospitals and indoor environments [6; 7; 8]. In comparison to RF, the VLC spectrum is 10,000 times the RF spectrum, license free, and unregulated, hence it could be used for data communication [9]. VLC deploys light waves for communication, which are insensitive to electronic equipment; therefore, free from electromagnetic interference and thus best suited in healthcare applications, especially in RF-restricted areas such as intensive care units (ICUs) [10; 11]. Since the lights are easily blocked by non-transparent object such as walls, hence visible light communication is more secure in comparison to RF, infrared (IR) and ultraviolet (UV) communications [12]. Additionally, the light confines the information to optics and within the premises of a VLC-based system, hence VLC does not suffer from eavesdropping [13]. Hence, in past years, several studies were conducted on visible light communication in different areas of research, such as indoor positioning [6; 13; 14; 15; 16], vehicle-to-vehicle communication [7; 17; 18; 19], environmental monitoring [8; 20], and IoT applications [21; 22]. It is due to the capability of providing both illumination and data communication unlike other OWC systems. Nowadays, in VLC systems, the organic light-emitting diode (OLED) is replacing the conventionally-used transmitter, such as the white LED, because of low cost and flexibility [9; 10]; however, the VLC-based LEDs/OLED systems employ a photodiode (PD) as the receiver (Rx). The VLC systems deploying a conventional PD as the receiver requires hardware modifications due to additional filters and amplifier circuitry; therefore, in order to provide low-cost flexible wireless communications, a camera is the best solution to be deployed as the receiver in VLC systems [10; 11]. Cameras are ubiquitous and increasingly being used not just for capturing images but also for communicating information. The universal access of Quick Response Code (QR) codes motivates deploying novel camera communication applications, where pervasive display screens could be modulated to send time varying QR codes to be decoded by video cameras. The pixel elements of the screen and camera can be leveraged to send data through time-varying 2D barcodes [11; 12; 13]. Optical camera communication is a recent development of OWC and an extension of VLC, where image sensors or cameras are used for sensing the light intensity emitted from a light emitter instead of conventional photodiodes. Optical camera communication (OCC) is a pragmatic version of visible light communication (VLC) using a camera as the receiver. OCC operates in the same channel band as VLC with more advantages on receiver characteristics and has been studied in the IEEE 802.15 S67a within the framework of optical wireless communications and considered as a candidate of IEEE 802.15.7 rl [12; 13; 14]. The OCC has an inherent advantage of capturing 2-dimensional (2D) image data, compared with intensity level-based photodiodes in VLC [12].