Li-Fi_Reciver

// Receiver Code: Reads light pulses and decodes binary data

const int sensorPin = A0;  // Light sensor connected to analog pin A0
const int threshold = 750;  // Threshold to detect light intensity
int startRead = 0;
String receivedMessage = "";

void setup() {
  Serial.begin(9600);  // Start serial communication
  pinMode(sensorPin, INPUT);

}

void loop() {
  int sensorValue = analogRead(sensorPin);  // Read light sensor value

      if (sensorValue > threshold && startRead == 0) { // when the sensor recieves the inisilization light, syncing begins. 
      Serial.println("reading");                       // just a bit to see that the computer is actually reading
      delay(2000);                                     //delay allows for computers to be intime with eachother. 
      startRead = 1;
     }
  if (startRead == 1) {
    sensorValue = analogRead(sensorPin);  // Read light sensor value

    if (sensorValue > threshold) { 
        receivedMessage += "1";  // Light detected, make a 1

    } else {
        receivedMessage += "0";  // No light detected, makes a 0
    }
      Serial.println(receivedMessage);

    delay(1000);  // Wait for the next bit
    if (receivedMessage.length() >= 8) {  // Ensure full 8-bit message, nothing less.
        int decimalValue = binaryToDecimal(receivedMessage);  // Convert to decimal
        char asciiChar = (char)decimalValue;  // Convert decimal to ASCII

        Serial.print("Received Binary: ");
        Serial.print(receivedMessage);
        Serial.print(" | Decimal: ");
        Serial.print(decimalValue);
        Serial.print(" | ASCII: ");
        Serial.write(decimalValue);  // Print ASCII character directly
        Serial.println();  // New line for clarity

        receivedMessage = "";  // Clear message for the next cycle
        delay(5000);  // Wait before restarting
    }
}
}
// Function to convert an 8-bit binary string to decimal
int binaryToDecimal(String binary) {
    int decimalValue = 0;

    for (int i = 0; i < 8; i++) {
        if (binary[i] == '1') {
            decimalValue |= (1 << (7 - i));  // Bitwise conversion from string to decimal. 
        }
    }

    return decimalValue;
}