A Simple Concept of Lifi-Visible light communication for Audio Transmission using a low-cost component.
The technology truly began during the 1990s in countries like Germany, Korea, and Japan where they discovered that LEDs could be used to send information. Harald Haas continues to show the world the potential to use light for communication.
The technology was named LIFI, which can be simply defined as the transmission of data through a LED light bulb that varies intensity faster than the human eye can follow.
HOW LI-FI WORKS
Figure 1 shows the working principle of the Li-Fi system, for data transmission; it can be done by a single LED or multi LED. The lamp driving circuit consists of a control circuit and output stage to modify the data and make it ready to be sent.
The operational procedure is very simple if the LED is on, you transmit a digit ‘1’, or data is transmitted if it is off you transmit a ‘0’, and data is not transmitted.
The receiver side consists of a photodetector connected to an amplifier to demodulate the signals received by the photodetector.
APPLICATIONS
- Underwater Communications.
- Traffic Management.
- Airways.
- Medical Application.
- Blind Indoor Navigation System.
- Disaster Management. Etc
WHAT WE USED FOR SIMPLE AUDIO TRANSMISSION
In our practice experiment, we used some low-cost components bought online to illustrate the working principle of Li-Fi system for Audio Transmission. we illustrate those components in figure 2.
Transmission section
In the transmission section, there is a LED, a battery and an auxiliary cable (AUX) for audio transmission. The AUX also is known as audio jack receive signals form device and transfer analog audio signals to the LED which drives the LED using on-off-keying (OOK) Modulation. If the LED is on, it transmits a digital 1 otherwise it transmits a digital 0. The LEDs is switched on and off quickly to transmit data that can’t be detected by a human eye.
Amplifier Module 1
Description:
Bluetooth voice player. It supports Bluetooth wireless connections. Smart home playback.
From diagrams 1 and 2 are power input.
3 and 4 are for communication (transmission).
2 and 4 are USB Port and AUX port.
1 and 3 are alternative to 2 and 4.
we only use the Bluetooth of the Amplifier Module 1 to receive audio from a device to make the transmission module portable and wireless but we can use an AUX cable for communication between the device and the Amplifier.
Receiving Section
On the receiver section, there is a solar panel, which converts this light into electric signals and it will pass the electric signals to the PAM8403 audio amplifier. The photodetector, in this case, the solar panel absolved the ones and zeros from the LED source. These signals (ones and zeros) are demodulated and amplified by the audio amplifier. The light intensity is absorbed by a solar panel then the audio signal comes out using a speaker.
Amplifier Module 2
Description:
The PAM8403 is a 3W, class-D audio amplifier. It offers low THD+N, allowing it to achieve high-quality sound reproduction.
From figure 6, the AUX cable serves as an input source of the module, we remove the AUX and replace it with a Solar panel which will receive the light signals from our Transmitting module.
The complete conceptual architecture of the design is illustrated in figure 8.
SUMMARY
The point of this presentation is to illustrate and visualize the conceptual design of LIFI for audio transmission using some pre-programmed low-cost module to understand the concept of (VLC) visible light communication and to learn more about visible light communication visit the provided reference.
Thank You for Reading…
REFERENCE
[1] Prerna Chauhan, Ritika Tripathi Jyoti Rani, “Li-Fi (Light Fidelity)-The future technology In Wireless communication,” International Journal of Applied Engineering Research, Nov 2012.
[2] M. Mutthamma, “A survey on Transmission of data through illumination — Li-Fi,” International Journal of Research in Computer and, Dec 2013.
[3] (2015) Wikipedia. [Online]. http://en.wikipedia.org/wiki/Visible_light_communication
[4] Raafat Ali Ali, “Light Fidelity (Li-Fi) Technology ” Higher Institute for Applied Sciences and Technology
Communications Department 4th year, SEMINAR, April 2nd, 2015.
[5] https://www.diodes.com/assets/Datasheets/PAM8403.pdf
