333 lines
8.4 KiB
Markdown
333 lines
8.4 KiB
Markdown
# ESP32 8-Channel Bluetooth Relay Controller
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A comprehensive ESP32-based 8-channel relay controller with Bluetooth connectivity for wireless control via smartphone or computer.
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## Features
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- ✅ Control 8 independent relays via Bluetooth
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- ✅ Simple text-based command protocol
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- ✅ Individual relay on/off/toggle control
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- ✅ All relays on/off commands
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- ✅ Status query for all relays
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- ✅ Persistent state memory (remembers relay states after reboot)
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- ✅ Easy integration with mobile apps (Serial Bluetooth Terminal, etc.)
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- ✅ Compatible with Home Assistant via Bluetooth Serial integration
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## Hardware Requirements
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### Essential Components
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1. **ESP32 Development Board**
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- Any ESP32 board with Bluetooth (ESP32-DevKitC, ESP32-WROOM, etc.)
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- Minimum 8 GPIO pins available
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2. **8-Channel Relay Module**
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- 5V or 3.3V trigger relay module
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- Recommended: Active LOW trigger relays
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- Options:
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- Single 8-channel relay board
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- Two 4-channel relay boards
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- Individual relay modules
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3. **Power Supply**
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- 5V power supply for ESP32 (USB or external)
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- Separate power for relay coils if using high-current loads
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- Recommended: 5V 2A+ power supply
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4. **Wiring Components**
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- Jumper wires (male-to-male, male-to-female)
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- Breadboard (optional for prototyping)
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- Terminal blocks (for AC/DC load connections)
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### Optional Components
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- Enclosure/project box
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- Status LEDs (already on most relay modules)
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- Fuse holders for safety
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- PCB for permanent installation
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## Wiring Diagram
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### GPIO Pin Assignments (Default)
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| Relay # | ESP32 GPIO | Relay Module Pin |
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|---------|------------|------------------|
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| Relay 1 | GPIO 13 | IN1 |
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| Relay 2 | GPIO 12 | IN2 |
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| Relay 3 | GPIO 14 | IN3 |
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| Relay 4 | GPIO 27 | IN4 |
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| Relay 5 | GPIO 26 | IN5 |
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| Relay 6 | GPIO 25 | IN6 |
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| Relay 7 | GPIO 33 | IN7 |
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| Relay 8 | GPIO 32 | IN8 |
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### Power Connections
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```
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ESP32 8-Channel Relay Module
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----- ----------------------
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GND -----------------> GND
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5V -----------------> VCC (or separate 5V supply)
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GPIO13 -----------------> IN1
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GPIO12 -----------------> IN2
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GPIO14 -----------------> IN3
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GPIO27 -----------------> IN4
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GPIO26 -----------------> IN5
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GPIO25 -----------------> IN6
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GPIO33 -----------------> IN7
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GPIO32 -----------------> IN8
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```
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### Load Connections (Per Relay)
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Each relay has three terminals:
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- **COM (Common)**: Connect to power source
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- **NO (Normally Open)**: Connects to COM when relay is ON
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- **NC (Normally Closed)**: Connects to COM when relay is OFF
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**Example for controlling AC devices:**
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```
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AC Live Wire --> Relay COM
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Relay NO --> Device Live Wire
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AC Neutral --> Device Neutral (direct connection)
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```
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⚠️ **WARNING**: Working with AC power is dangerous! Only attempt if you're qualified. Consider using DC loads for initial testing.
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## Software Setup
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### Arduino IDE Setup
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1. **Install ESP32 Board Support**
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- Open Arduino IDE
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- Go to File → Preferences
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- Add to "Additional Board Manager URLs":
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```
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https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
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```
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- Go to Tools → Board → Board Manager
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- Search for "ESP32" and install
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2. **Configure Board Settings**
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- Board: "ESP32 Dev Module" (or your specific board)
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- Upload Speed: 115200
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- Flash Frequency: 80MHz
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- Partition Scheme: "Default 4MB with spiffs"
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3. **Upload the Code**
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- Open `esp32_bluetooth_relay.ino`
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- Select your ESP32 board and COM port
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- Click Upload
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### PlatformIO Setup (Alternative)
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If using PlatformIO:
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```ini
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[env:esp32dev]
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platform = espressif32
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board = esp32dev
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framework = arduino
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monitor_speed = 115200
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lib_deps =
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BluetoothSerial
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```
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## Usage
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### Connecting via Bluetooth
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1. **Power on the ESP32**
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- The device will appear as "ESP32-Relay-8CH"
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2. **Pair the Device**
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- On your phone/computer, search for Bluetooth devices
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- Connect to "ESP32-Relay-8CH"
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- Default PIN: 1234 (if prompted)
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3. **Use a Serial Bluetooth Terminal**
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- Android: "Serial Bluetooth Terminal" app
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- iOS: "Bluetooth Terminal" app
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- Windows: PuTTY with Bluetooth COM port
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- Linux: `bluetoothctl` and `minicom`
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### Command Reference
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| Command | Description | Example |
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|---------|-------------|---------|
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| `ON1` - `ON8` | Turn on specific relay | `ON1` turns on Relay 1 |
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| `OFF1` - `OFF8` | Turn off specific relay | `OFF5` turns off Relay 5 |
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| `TOGGLE1` - `TOGGLE8` | Toggle specific relay | `TOGGLE3` toggles Relay 3 |
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| `ALL_ON` | Turn all relays on | `ALL_ON` |
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| `ALL_OFF` | Turn all relays off | `ALL_OFF` |
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| `STATUS` | Get status of all relays | `STATUS` |
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| `HELP` | Show available commands | `HELP` |
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Commands are **case-insensitive** and should be sent with a newline character.
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### Example Session
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```
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> STATUS
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=== Relay Status ===
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Relay 1: OFF
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Relay 2: OFF
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Relay 3: ON
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Relay 4: OFF
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Relay 5: OFF
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Relay 6: OFF
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Relay 7: OFF
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Relay 8: OFF
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===================
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> ON1
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Relay 1 is now ON
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> TOGGLE3
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Relay 3 is now OFF
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> ALL_ON
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All relays turned ON
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```
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## Customization
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### Changing GPIO Pins
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Edit the `relayPins` array in the code:
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```cpp
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const int relayPins[8] = {13, 12, 14, 27, 26, 25, 33, 32};
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```
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### Changing Bluetooth Device Name
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Edit the `deviceName` constant:
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```cpp
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const char* deviceName = "YourCustomName";
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```
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### Changing Relay Names
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Edit the `relayNames` array:
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```cpp
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const char* relayNames[8] = {
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"Living Room", "Bedroom", "Kitchen", "Bathroom",
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"Garden", "Garage", "Office", "Workshop"
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};
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```
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### Active HIGH vs Active LOW Relays
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Most relay modules are **active LOW** (relay turns ON when GPIO is LOW). If you have active HIGH relays, change:
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```cpp
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// In setRelay() function, change:
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digitalWrite(relayPins[relayIndex], state ? LOW : HIGH);
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// to:
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digitalWrite(relayPins[relayIndex], state ? HIGH : LOW);
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```
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## Home Assistant Integration
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### Method 1: Bluetooth Serial Integration
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1. Install the Bluetooth Serial integration in Home Assistant
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2. Add to `configuration.yaml`:
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```yaml
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bluetooth_serial:
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- address: "XX:XX:XX:XX:XX:XX" # ESP32 MAC address
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name: "ESP32 Relay Controller"
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switch:
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- platform: template
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switches:
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relay_1:
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friendly_name: "Relay 1"
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turn_on:
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service: bluetooth_serial.send
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data:
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address: "XX:XX:XX:XX:XX:XX"
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message: "ON1\n"
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turn_off:
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service: bluetooth_serial.send
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data:
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address: "XX:XX:XX:XX:XX:XX"
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message: "OFF1\n"
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```
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### Method 2: ESPHome (Alternative Firmware)
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For better Home Assistant integration, consider using ESPHome firmware instead. (Separate implementation recommended)
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## Troubleshooting
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### Bluetooth Not Showing Up
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- Ensure Bluetooth is enabled in your ESP32 build
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- Check if device is already paired with another device
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- Try restarting the ESP32
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### Relays Not Switching
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- Verify wiring connections
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- Check if relay module requires 5V and you're providing it
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- Test with a multimeter
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- Verify GPIO pins are correctly defined
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### Intermittent Connection
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- Move closer to ESP32
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- Check power supply stability
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- Ensure no interference from other Bluetooth devices
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### Relays Switching Opposite Direction
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- Your relay module might be active HIGH instead of active LOW
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- See "Active HIGH vs Active LOW Relays" section above
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## Safety Warnings
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⚠️ **ELECTRICAL SAFETY**
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- Never work on AC wiring while powered
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- Use proper insulation and enclosures
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- Follow local electrical codes
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- Consider hiring a licensed electrician for permanent installations
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- Test with low voltage DC loads first
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⚠️ **RELAY RATINGS**
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- Don't exceed relay current/voltage ratings
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- Use appropriate fuses
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- Account for inductive loads (motors, transformers)
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## License
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This project is open source and available under the MIT License.
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## Contributing
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Contributions are welcome! Please feel free to submit issues or pull requests.
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## Support
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For questions or issues:
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- Open an issue on the repository
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- Check existing issues for solutions
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- Consult ESP32 and Arduino forums
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## Future Enhancements
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Potential additions:
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- [ ] Web interface (ESP32 web server)
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- [ ] MQTT support for Home Assistant
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- [ ] Scheduling/timers
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- [ ] Mobile app development
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- [ ] WiFi connectivity option
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- [ ] Scene/macro support
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- [ ] Energy monitoring
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---
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**Version:** 1.0.0
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**Last Updated:** December 2025
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