Very simple and useful project to understand the working of Li-Fi, you can also make your own Li-Fi device with a bit more modifications to the design and code provided. You actually need two arduino's, one to send and the other to receive to make it more fun.

Step 1: Getting Started

Components needed

100 ohm resistor,

1 K resistor,

LED,

LDR,

Arduino Uno

Step 2: Setting Up Connections

Connect one end of 100 ohm resistor to pin number 13 and the other end to the positive terminal of led, the other end of led goes to GND pin. Also connect the ldr as shown. You can also use male to female jumper wires directly for connecting the resistor and ldr.

Step 3: Setting Up Even Light

As the ldr values depend upon the surrounding light and also led cannot emit even light I have used a small paper pipe and placed the led through one end and ldr at the other end of it.

Now you are all set to start coding.

Step 4: Code

//copy this code and start modifying

int sensorPin = A0; // select the input pin for ldr

int sensorValue = 0; // variable to store the value coming from the sensor

int light=0;

int i=0;

int d[32];

int temp=1;

int k=0; int add=0;

int a=1001;//-------------- replace with any value of your choice

void setup()

{ pinMode(13, OUTPUT); //pin connected to the relay

Serial.begin(9600); //sets serial port for communication

Serial.println(sensorPin);

int b;

while(a!=0)

{

b=a%2; //converts binary to decimal

a=a/2;

if(b==1)

{

digitalWrite(13,HIGH);

delay(2);

sensorValue=analogRead(sensorPin);

d[i]=sensorValue; }

else

{

digitalWrite(13,LOW);

delay(2);

sensorValue=analogRead(sensorPin);

d[i]=sensorValue;

}

i++;

} i--;

// for converting binary to decimal

while(i>=0)

{

if(d[i]>=75&&d[i]<700)

{

k=i;

while(k!=0)

{

temp=temp*2;

k--;

}

add=add+temp;

temp=1;

}

i--;

}

Serial.println(add); // Final recieved value gets printed

digitalWrite(13,LOW); }

void loop()

{

}

Step 5: Further Applications

You can make few changes to the code and make it work for characters and also you can use a light bulb instead of led which can give more light evenly than the led which is the actual concept of Li-Fi.

Enjoy.