esp32-bluetooth-relay/esp32_bluetooth_relay/esp32_bluetooth_relay.ino

/*
 * ESP32 8-Channel Bluetooth Relay Controller
 * 
 * Features:
 * - Control 8 relays via Bluetooth Serial
 * - Individual relay on/off control
 * - All relays on/off commands
 * - Status query for all relays
 * - Toggle individual relays
 * - Persistent state (remembers relay states on reboot)
 * 
 * Commands:
 * - ON1-8: Turn on relay 1-8
 * - OFF1-8: Turn off relay 1-8
 * - TOGGLE1-8: Toggle relay 1-8
 * - ALL_ON: Turn all relays on
 * - ALL_OFF: Turn all relays off
 * - STATUS: Get status of all relays
 * - HELP: Show available commands
 */

#include "BluetoothSerial.h"
#include <Preferences.h>

// Check if Bluetooth is enabled
#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to enable it
#endif

// Bluetooth Serial object
BluetoothSerial SerialBT;

// Preferences for persistent storage
Preferences preferences;

// Define relay pins (adjust these based on your ESP32 board)
const int relayPins[8] = {13, 12, 14, 27, 26, 25, 33, 32};

// Relay states (true = ON, false = OFF)
bool relayStates[8] = {false, false, false, false, false, false, false, false};

// Relay names for easier identification
const char* relayNames[8] = {
  "Relay 1", "Relay 2", "Relay 3", "Relay 4",
  "Relay 5", "Relay 6", "Relay 7", "Relay 8"
};

// Device name for Bluetooth
const char* deviceName = "ESP32-Relay-8CH";

// Command buffer
String commandBuffer = "";

void setup() {
  // Initialize serial for debugging
  Serial.begin(115200);
  Serial.println("\nESP32 8-Channel Bluetooth Relay Controller");
  Serial.println("==========================================");
  
  // Initialize preferences
  preferences.begin("relay-states", false);
  
  // Initialize relay pins
  for (int i = 0; i < 8; i++) {
    pinMode(relayPins[i], OUTPUT);
    
    // Load saved state from preferences
    relayStates[i] = preferences.getBool(String("relay" + String(i)).c_str(), false);
    
    // Set initial state (relays are typically active LOW)
    digitalWrite(relayPins[i], relayStates[i] ? LOW : HIGH);
    
    Serial.printf("Pin %d (%s): %s\n", relayPins[i], relayNames[i], 
                  relayStates[i] ? "ON" : "OFF");
  }
  
  // Initialize Bluetooth Serial
  if(!SerialBT.begin(deviceName)) {
    Serial.println("Bluetooth initialization failed!");
    while(1);
  }
  
  Serial.printf("\nBluetooth device \"%s\" is ready to pair!\n", deviceName);
  Serial.println("Waiting for Bluetooth connection...\n");
  
  // Print available commands
  printHelp();
}

void loop() {
  // Check for Bluetooth data
  while (SerialBT.available()) {
    char inChar = (char)SerialBT.read();
    
    // Add character to buffer
    if (inChar == '\n' || inChar == '\r') {
      // Process command when newline is received
      if (commandBuffer.length() > 0) {
        processCommand(commandBuffer);
        commandBuffer = "";
      }
    } else {
      commandBuffer += inChar;
    }
  }
  
  // Small delay to prevent watchdog issues
  delay(10);
}

void processCommand(String command) {
  command.trim();
  command.toUpperCase();
  
  Serial.printf("Received command: %s\n", command.c_str());
  
  // ON commands (ON1 through ON8)
  if (command.startsWith("ON") && command.length() == 3) {
    int relayNum = command.charAt(2) - '0';
    if (relayNum >= 1 && relayNum <= 8) {
      setRelay(relayNum - 1, true);
      return;
    }
  }
  
  // OFF commands (OFF1 through OFF8)
  if (command.startsWith("OFF") && command.length() == 4) {
    int relayNum = command.charAt(3) - '0';
    if (relayNum >= 1 && relayNum <= 8) {
      setRelay(relayNum - 1, false);
      return;
    }
  }
  
  // TOGGLE commands (TOGGLE1 through TOGGLE8)
  if (command.startsWith("TOGGLE") && command.length() == 7) {
    int relayNum = command.charAt(6) - '0';
    if (relayNum >= 1 && relayNum <= 8) {
      toggleRelay(relayNum - 1);
      return;
    }
  }
  
  // ALL_ON command
  if (command == "ALL_ON" || command == "ALLON") {
    setAllRelays(true);
    return;
  }
  
  // ALL_OFF command
  if (command == "ALL_OFF" || command == "ALLOFF") {
    setAllRelays(false);
    return;
  }
  
  // STATUS command
  if (command == "STATUS" || command == "STATE") {
    sendStatus();
    return;
  }
  
  // HELP command
  if (command == "HELP" || command == "?") {
    printHelp();
    return;
  }
  
  // Unknown command
  SerialBT.println("ERROR: Unknown command");
  Serial.println("ERROR: Unknown command");
  SerialBT.println("Type HELP for available commands");
}

void setRelay(int relayIndex, bool state) {
  if (relayIndex < 0 || relayIndex >= 8) return;
  
  relayStates[relayIndex] = state;
  
  // Relays are typically active LOW (relay on when pin is LOW)
  digitalWrite(relayPins[relayIndex], state ? LOW : HIGH);
  
  // Save state to preferences
  preferences.putBool(String("relay" + String(relayIndex)).c_str(), state);
  
  // Send confirmation
  String response = String(relayNames[relayIndex]) + " is now " + 
                    (state ? "ON" : "OFF");
  SerialBT.println(response);
  Serial.println(response);
}

void toggleRelay(int relayIndex) {
  if (relayIndex < 0 || relayIndex >= 8) return;
  
  setRelay(relayIndex, !relayStates[relayIndex]);
}

void setAllRelays(bool state) {
  for (int i = 0; i < 8; i++) {
    relayStates[i] = state;
    digitalWrite(relayPins[i], state ? LOW : HIGH);
    preferences.putBool(String("relay" + String(i)).c_str(), state);
  }
  
  String response = "All relays turned " + String(state ? "ON" : "OFF");
  SerialBT.println(response);
  Serial.println(response);
}

void sendStatus() {
  SerialBT.println("=== Relay Status ===");
  Serial.println("=== Relay Status ===");
  
  for (int i = 0; i < 8; i++) {
    String status = String(relayNames[i]) + ": " + 
                    (relayStates[i] ? "ON" : "OFF");
    SerialBT.println(status);
    Serial.println(status);
  }
  
  SerialBT.println("===================");
  Serial.println("===================");
}

void printHelp() {
  const char* helpText = R"(
=== Available Commands ===
ON1-8      : Turn on relay 1-8 (e.g., ON1, ON5)
OFF1-8     : Turn off relay 1-8 (e.g., OFF1, OFF8)
TOGGLE1-8  : Toggle relay 1-8 (e.g., TOGGLE1)
ALL_ON     : Turn all relays on
ALL_OFF    : Turn all relays off
STATUS     : Get current status of all relays
HELP       : Show this help message
==========================
)";
  
  SerialBT.print(helpText);
  Serial.print(helpText);
}