As part of innovative Arduino Robots Projects, this experiment explores Li-Fi technology, which is based on the principle of Visible Light Communication (VLC) — where variations in light intensity represent binary data. Unlike Wi-Fi, which relies on radio frequency signals, Li-Fi uses the visible light spectrum, offering a high-speed, secure, and low-cost method for wireless data transmission.
In this project, the transmitter Arduino reads a message from the Serial input and converts it into binary pulses. An LED then turns ON and OFF rapidly to transmit the 1s and 0s through light. On the receiving end, a solar panel or LDR (Light Dependent Resistor) detects these light pulses. The receiver Arduino interprets the incoming signals, converts them back into readable characters, and displays the message on the Serial Monitor.
This Arduino Robots Projects example demonstrates how microcontrollers can be used to explore advanced communication technologies and introduces learners to the fascinating world of optical data transfer and embedded systems innovation.
Components Required
Component | Quantity | Description |
Arduino Uno / Nano | 2 | One for transmitter, one for receiver |
LED (White or IR) | 1 | For transmitting data via light |
Resistor 220 Ω | 1 | Limits current through LED |
Solar panel or LDR | 1 | Detects transmitted light |
Jumper wires | – | For connections |
Breadboard | 1 | For easy wiring |
USB cables | 2 | For programming and Serial communication |
Circuit Description
Transmitter Side
- LED anode connected to Arduino pin 9 through a 220 Ω resistor.
- LED cathode connected to GND.
- Arduino sends ON/OFF pulses to represent binary data of characters typed in the Serial Monitor.
Receiver Side
- Solar panel +ve (or LDR output node) connected to A0 (analog input).
- Solar panel –ve connected to GND.
- Arduino continuously reads analog values from A0, detects changes in light intensity, and reconstructs the transmitted character.
📘 Tip: Keep LED and solar panel aligned directly facing each other at 5–10 cm distance for best performance.
DIAGRAM
Testing the Hardware
- Step 1 – Test LED Output:
Upload a simple LED blink code to confirm the LED turns ON and OFF properly. - Step 2 – Test Receiver Response:
Upload a small analog read code to check if the receiver (solar panel/LDR) values change when LED blinks. - Step 3 – Align Components:
Keep LED directly facing the solar panel/LDR.
Reduce ambient light for stable readings.
- Step 4 – Upload Final Transmitter and Receiver Codes
Open both Serial Monitors at 9600 baud.
Type text (e.g., HELLO#) in the transmitter Serial Monitor.
The receiver should print the same text.
Troubleshooting Guide
Problem | Possible Cause | Solution |
No data received | LED not connected or misaligned | Check LED wiring and polarity |
Garbled characters (⸮X⸮-) | Timing mismatch | Increase BIT_DELAY to 10–15 ms in both codes |
Receiver shows no light variation | Weak LED or too far distance | Use a brighter LED, reduce distance |
Receiver always shows same value | Solar panel/LDR not facing LED | Adjust alignment or use shield to block other light |
Works in dark but not in bright light | Ambient light interference | Use black tube or cover around LED and receiver to isolate path |
Receiver unstable | Noise in analog readings | Use averaging or add 10 kΩ resistor parallel to sensor |
( This project demonstrates a simple Li-Fi (Light Fidelity) communication system using Arduino, offering an exciting introduction to the world of optical wireless communication. Li-Fi is a form of wireless data transfer that uses visible light instead of traditional radio waves like Wi-Fi, making it faster, more secure, and less prone to electromagnetic interference.
In this setup, one Arduino board acts as the transmitter, converting digital data into rapid LED blinks that represent binary signals (1s and 0s). A solar panel or LDR (Light Dependent Resistor) serves as the receiver, detecting these changes in light intensity and converting them back into electrical signals. The receiving Arduino processes these signals and reconstructs the transmitted message for display on the Serial Monitor.
This project not only highlights the concept of short-distance, secure, and interference-free communication but also demonstrates how Arduino-based systems can be used to explore cutting-edge technologies. It’s an excellent choice for students, hobbyists, and makers interested in learning about Arduino Robot Projects, data transmission principles, and the future of light-based networking in smart devices and IoT systems. )