HC-05 Bluetooth
Module Setup Guide

// HC-05 Bluetooth Module — AT Command Bridge
// Use ONLY while the module is in AT mode (see steps above).
// Serial Monitor: 38400 baud, line ending "Both NL & CR"
// Wiring: VCC→5V | GND→GND | TXD→D2 | RXD→D3 (via divider)

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(2, 3); // RX, TX

void setup() {
  Serial.begin(38400);   // Serial Monitor — AT mode baud rate
  BTSerial.begin(38400); // HC-05 AT mode baud rate
  Serial.println("AT bridge ready. Try typing: AT");
}

void loop() {
  if (BTSerial.available()) Serial.write(BTSerial.read());
  if (Serial.available()) BTSerial.write(Serial.read());
}

// HC-05 Bluetooth Module — Serial Passthrough Test
// Tishvi Docs · Wiring: VCC→5V | GND→GND | TXD→D2 | RXD→D3 (via divider)

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(2, 3); // RX, TX — D2←TXD, D3→RXD

void setup() {
  Serial.begin(9600);
  BTSerial.begin(9600); // HC-05 default data-mode baud rate

  Serial.println("HC-05 ready. Pair with 'HC-05' on your phone (PIN 1234 or 0000).");
}

void loop() {
  // Anything from the phone app → printed on Serial Monitor
  if (BTSerial.available()) {
    Serial.write(BTSerial.read());
  }
  // Anything typed in Serial Monitor → sent to the phone app
  if (Serial.available()) {
    BTSerial.write(Serial.read());
  }
}

// HC-05 Bluetooth Module — LED Control
// Send '1' to turn the LED on, '0' to turn it off, from any
// Bluetooth serial terminal app.
// Wiring: VCC→5V | GND→GND | TXD→D2 | RXD→D3 (via divider) | LED→pin 13

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(2, 3); // RX, TX
const int ledPin = 13;

void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
  BTSerial.begin(9600);
  Serial.println("Send '1' or '0' from your phone to control the LED.");
}

void loop() {
  if (BTSerial.available()) {
    char cmd = BTSerial.read();

    if (cmd == '1') {
      digitalWrite(ledPin, HIGH);
      BTSerial.println("LED ON");
    } else if (cmd == '0') {
      digitalWrite(ledPin, LOW);
      BTSerial.println("LED OFF");
    }
  }
}