ESP32 Smart Intercom Project

A comprehensive ESP32-based itercom system with WiFi connectivity, MQTT communication, GPIO monitoring, and RGB status indication.

Features

• WiFi Connectivity: Automatic connection to WiFi networks with reconnection handling
• MQTT Communication: MQTT5 client with automatic reconnection and message handling
• GPIO Monitoring: ADC monitoring with threshold-based alerts
• RGB Status Indicator: Visual status indication through RGB LED
• Remote Control: GPIO control via MQTT messages
• Over-The-Air Updates (OTA): Remote firmware updates via HTTP
• Modular Architecture: Clean separation of concerns with task-based design

Hardware Requirements

• ESP32 development board
• RGB LED (Common Cathode)
• ADC input sensor/potentiometer (Connect to your Intercom Tube LED)
• GPIO output device (Connect to button to open door)

Pin Configuration

RGB LED

• Red: GPIO 13
• Green: GPIO 12
• Blue: GPIO 14

GPIO Control

• Output Pin: GPIO 2

ADC Monitoring

• Input Channel: ADC1_Channel_6 (GPIO 34)

Project Structure

main/
├── app_main.c              # Main application entry point
├── credentials.example.h    # WiFi and MQTT credentials template
├── intercom_constants.h     # Hardware pin definitions and constants
├── color.h                 # Color utility definitions
└── tasks/
    ├── rgb_state_task.h/.c    # RGB LED control and status indication
    ├── wifi_task.h/.c         # WiFi connection management
    ├── mqtt_task.h/.c         # MQTT client implementation
    ├── gpio_monitor_task.h/.c # ADC monitoring and GPIO control
    └── ota_task.h/.c          # Over-The-Air update functionality

Setup Instructions

1. Clone and Configure

git clone https://github.com/verncat/ESP32-Intercom.git
cd ESP32-Intercom

2. Configure Credentials

Copy the example credentials file and edit with your settings:

cp main/credentials.example.h main/credentials.h

Edit main/credentials.h:

#define WIFI_SSID       "YourWiFiSSID"
#define WIFI_PASS       "YourWiFiPassword"
#define MQTT_BROKER_URL "mqtt://your-mqtt-broker.local"
#define MQTT_USERNAME   "your-mqtt-username"
#define MQTT_PASSWORD   "your-mqtt-password"

// OTA Configuration
#define OTA_FIRMWARE_UPG_URL "http://your-server.local:8080/firmware.bin"
#define OTA_FIRMWARE_RECV_TIMEOUT 10000

3. Build and Flash

idf.py build
idf.py flash monitor

MQTT Topics

Subscribed Topics

• /topic/intercom/open_state: Controls GPIO 2
  • Send "true" or "1" to set GPIO HIGH
  • Send "false" or "0" to set GPIO LOW

Published Topics

• /topic/intercom/dial_value: ADC readings when threshold is exceeded
  • Publishes raw ADC value as string

RGB Status Indicators

The RGB LED provides visual feedback for different system states:

WiFi States

• Light Blue (Blinking): WiFi connecting
• Light Green (Solid): WiFi connected
• Orange (Blinking): WiFi disconnected

MQTT States

• Purple (Blinking): MQTT connecting
• Green (Solid): MQTT connected
• Yellow (Blinking): MQTT disconnected
• Magenta (Blinking): MQTT sending message
• Cyan (Blinking): MQTT receiving message

General States

• Black/Off: System idle
• Red (Blinking): Error state

OTA States

• White (Blinking): OTA update in progress
• Green (Blinking): OTA update successful
• Red (Fast Blinking): OTA update failed

System States

The system tracks the following states:

enum IntercomState {
    ENUM_INTERCOM_STATE_IDLE,
    ENUM_INTERCOM_STATE_WIFI_CONNECTING,
    ENUM_INTERCOM_STATE_WIFI_CONNECTED,
    ENUM_INTERCOM_STATE_WIFI_DISCONNECTED,
    ENUM_INTERCOM_STATE_MQTT_CONNECTING,
    ENUM_INTERCOM_STATE_MQTT_CONNECTED,
    ENUM_INTERCOM_STATE_MQTT_DISCONNECTED,
    ENUM_INTERCOM_STATE_MQTT_SENDING,
    ENUM_INTERCOM_STATE_MQTT_RECEIVING,
    ENUM_INTERCOM_STATE_OTA_UPDATING,
    ENUM_INTERCOM_STATE_OTA_SUCCESS,
    ENUM_INTERCOM_STATE_OTA_FAILURE,
};

Configuration

ADC Monitoring

• Threshold: 2000 (12-bit ADC value)
• Sampling Rate: 1 second
• Resolution: 12-bit (0-4095)

MQTT Settings

• Protocol: MQTT v5.0
• QoS: 1 (At least once delivery)
• Reconnection: Automatic with 3-second delay

Debugging

Enable verbose logging for troubleshooting:

esp_log_level_set("mqtt_client", ESP_LOG_VERBOSE);
esp_log_level_set("wifi", ESP_LOG_VERBOSE);

Monitor output:

idf.py monitor

Architecture

The project uses a modular, task-based architecture:

1. Main Task: Initializes all components and starts other tasks
2. RGB Task: Continuously updates LED status based on system state
3. WiFi Task: Handles WiFi connection and reconnection
4. MQTT Task: Manages MQTT connection and message handling
5. GPIO Monitor Task: Monitors ADC input and publishes values
6. OTA Task: Handles over-the-air firmware updates

Over-The-Air (OTA) Updates

The system supports remote firmware updates via HTTP without requiring physical access to the device.

OTA Configuration

Server Setup

Set up an HTTP server to host firmware files:

# Example using Python HTTP server
cd /path/to/firmware/directory
python3 -m http.server 8080

Firmware Preparation

1. Build your firmware:

   idf.py build

2. Copy the firmware binary:

   cp build/smart-intercom.bin /path/to/firmware/directory/firmware.bin

URL Configuration

Update your credentials.h with the firmware URL:

#define OTA_FIRMWARE_UPG_URL "http://192.168.1.100:8080/firmware.bin"