Merge pull request '[PR] Create lifecycle node' (#10) from 2-imu-reader/lifecycle-node into 2-imu-reader/master

Reviewed-on: http://git.wessel.gg/inholland/ros2-assignments/pulls/10

.gitignore

@@ -31,6 +31,7 @@ qtcreator-*
 
 # Colcon custom files
 COLCON_IGNORE
+!src/*/COLCON_IGNORE
 AMENT_IGNORE
 
 .vscode

doc/architecture/architecture.md

@@ -33,14 +33,23 @@ The system consists of multiple ROS2 nodes that communicate through standardized
 
 *For detailed documentation, see: [IMUDatabaseWriter.md](nodes/IMUDatabaseWriter.md)*
 
-#### 2. LifeCycle Node - NEEDS TO BE EDITED STILL
-**Namespace**: `assignments::one::grade_calculator`
+#### 2. LifeCycle Node
+**Namespace**: `assignments::two::lifecycle_manager`
 
-**Brief Description**: Provides grade calculation service with business logic including bonus points and grade validation.
+**Brief Description**: Configures low level communication and manages the hardware interface to read on either serial or mqtt comunications.
 
-**Key Features**: Average calculation, special student rules, grade bounds validation (10-100)
+**Key Features**: Configuration of communications, device read activation and deactivation.
 
-*For detailed documentation, see: [GradeCalculator.md](nodes/GradeCalculator.md)*
+*For detailed documentation, see: [LifecycleManager.md](nodes/LifecycleManager.md)*
+
+#### 3. Hardware Interface
+**Namespace**: `assignments::two::hardware_interface`
+
+**Brief Description**: Manages low-level communication protocols (Serial/MQTT) for ESP32 data acquisition and forwards raw sensor data to processing nodes.
+
+**Key Features**: Multi-protocol communication support, connection management, raw data parsing and streaming.
+
+*For detailed documentation, see: [HardwareInterface.md](nodes/HardwareInterface.md)*
 
 ### Data Management
 
@@ -65,7 +74,7 @@ The system consists of multiple ROS2 nodes that communicate through standardized
 
 ## System Workflow
 
-### 1. Exam Result Processing
+### 1. Imu data  Processing
 
 1. **Input**: IMU data is sent from the ESP32 to the lifecycle node
 2. **Collection**: The lifcycle node recieves the data via a serial or MQTT connection

doc/architecture/nodes/HardwareInterface.md

@@ -0,0 +1,355 @@
+# HardwareInterface (`assignments::two::g2_2025_lifecycle_node`)
+
+## Overview
+The `HardwareInterface` is a c++ class responsible for managing low-level hardware communication with ESP32-IMU combination via serial/MQTT and provides JSON parsing of sensor data, and publishes standardized `sensor_msgs::msg::Imu` messages to the database writer.
+
+#### Implementation Details
+
+**Public Methods**
+
+- **`start_read()`**: Spawns a background thread that continuously reads JSON payloads from the serial device
+- **`stop_read()`**: Signals the reader thread to exit and joins it for clean shutdown
+- **`write(const std::string& data)`**: Writes data to the serial device
+- **`open_device(const std::string& device_path, int baud_rate)`**: Opens and configures a serial port
+- **`is_device_open()`**: Checks if the serial device is currently open
+- **`close_device()`**: Closes the serial port and releases resources
+- **`mqtt_configure()`**: Initializes MQTT client and broker connection setup
+- **`mqtt_reader()`**: Attaches MQTT callbacks to begin receiving messages
+- **`mqtt_connect()`**: Establishes connection to the MQTT broker and subscribes to topics
+- **`close_mqtt_conn()`**: Disconnects from broker and cleans up MQTT resources
+- **`parse_data(const std::string& data)`**: Parses JSON payload into `sensor_msgs::msg::Imu` and publishes
+- **`publish_imu_data(const sensor_msgs::msg::Imu::SharedPtr msg)`**: Publishes an IMU message to the ROS topic
+
+**Constructor**
+
+```cpp
+HardwareInterface()
+```
+
+- Initializes ROS2 node with name `hardware_interface`
+- Creates a ROS2 publisher for `sensor_msgs::msg::Imu` on topic `imu_data` with queue size 10
+- Logs initialization status
+
+**Member Variables**
+
+- **`serialib serial`**: Encapsulates serial port communication
+- **`std::shared_ptr<mqtt::async_client> mqtt_client`**: Persistent MQTT async client for broker communication
+- **`std::shared_ptr<mqtt::callback> mqtt_cb`**: MQTT callback handler for message arrival events
+- **`std::thread read_thread_`**: Background reader thread for continuous serial data acquisition
+- **`std::atomic_bool reading_`**: Thread-safe flag to signal the reader thread to stop
+- **`std::string partial_buffer_`**: Accumulates fragmented serial reads until complete messages are available
+- **`rclcpp::Publisher<sensor_msgs::msg::Imu>::SharedPtr imu_publisher`**: ROS2 publisher for IMU data
+
+**MQTT Constants**
+
+- **`SERVER_ADDRESS`**: `"tcp://localhost:1883"` — Default MQTT broker address
+- **`CLIENT_ID`**: `"cpp_mqtt_client"` — MQTT client identifier
+- **`TOPIC`**: `"esp32/imu"` — Default subscription topic for IMU data
+
+## Core Functions
+
+### `void start_read()`
+
+Initiates continuous serial data acquisition in a background thread.
+
+**Behavior:**
+- Checks if a reader thread is already running; returns if so
+- Sets the `reading_` atomic flag to true
+- Spawns a thread that:
+  1. Allocates a 116-byte buffer
+  2. Enters a loop that runs while `reading_` is true
+  3. Calls `serial.readString()` with a 1-second timeout
+  4. Accumulates received bytes into `partial_buffer_`
+  5. Splits on newline (`\n`) to extract complete lines
+  6. Trims whitespace and strips leading garbage up to the first `{`
+  7. Validates that a closing `}` exists; if not, waits for more data
+  8. Calls `parse_data()` on each complete JSON line
+- Returns immediately while the thread continues running
+
+**Error Handling:**
+- Invalid JSON lines are logged as errors in `parse_data()` but do not crash the thread
+
+### `void stop_read()`
+
+Cleanly terminates the background reader thread.
+
+**Behavior:**
+- Returns immediately if not currently reading
+- Sets `reading_` atomic flag to false to signal the thread
+- Joins the thread to wait for its completion
+- Ensures all resources are released before returning
+
+**Thread Safety:**
+- Uses atomic flag for lock-free signaling
+- Blocks until thread joins, guaranteeing clean shutdown
+
+### `void parse_data(const std::string& data)`
+
+Deserializes a JSON string into a ROS2 IMU message and publishes it.
+
+**Behavior:**
+- Attempts to parse the input string as JSON using `nlohmann::json`
+- Creates a new `sensor_msgs::msg::Imu` message and populates:
+  - **Header**: Sets `stamp` to current time via `this->now()` and `frame_id` to `"imu_link"`
+  - **Linear Acceleration**: Extracts from JSON `"accel"` object fields `"x"`, `"y"`, `"z"` (defaults to 0.0 if missing)
+  - **Angular Velocity**: Extracts from JSON `"gyro"` object fields `"x"`, `"y"`, `"z"` (defaults to 0.0 if missing)
+- Logs the parsed IMU values at INFO level
+- Calls `publish_imu_data()` to send the message to the ROS topic
+
+**Expected JSON Format:**
+```json
+{
+  "accel": {"x": 0.037, "y": -1.164, "z": 9.775},
+  "gyro": {"x": -0.024, "y": -0.014, "z": -0.001},
+  "Temp": 41.01
+}
+```
+
+**Error Handling:**
+- Catches `nlohmann::json::exception` and logs parsing errors without crashing
+- Handles missing fields gracefully using `.value()` with default 0.0
+
+### `void publish_imu_data(const sensor_msgs::msg::Imu::SharedPtr msg)`
+
+Publishes an IMU message to the ROS2 topic.
+
+**Behavior:**
+- Dereferences the shared pointer and publishes to `imu_publisher`
+- Operation is thread-safe (rclcpp publishers support multi-threaded access)
+
+### `void mqtt_configure()`
+
+Sets up the MQTT infrastructure for broker communication.
+
+**Behavior:**
+- Creates a persistent `mqtt::async_client` pointing to `SERVER_ADDRESS` if not already created
+- Creates a persistent MQTT callback handler if not already created
+- Calls `mqtt_connect()` to establish the connection
+
+**Rationale for Persistence:**
+- Client and callback objects must outlive this function to maintain the connection
+- Using `shared_ptr` ensures proper lifetime management
+
+### `void mqtt_reader()`
+
+Attaches callbacks to the MQTT client to begin receiving messages.
+
+**Behavior:**
+- Sets the callback handler on the async client via `mqtt_client->set_callback(*mqtt_cb)`
+- Logs that the listener has started
+- Returns; the async client handles message reception in background threads
+
+### `void mqtt_connect()`
+
+Establishes connection to the MQTT broker and subscribes to the sensor topic.
+
+**Behavior:**
+- Creates `mqtt::connect_options` with:
+  - Keep-alive interval: 20 seconds
+  - Clean session: true (no prior session state restored)
+- Calls `mqtt_client->connect()` and waits for completion
+- Subscribes to `TOPIC` (default: `"esp32/imu"`) with QoS level 1
+- Logs successful connection and subscription
+
+**Error Handling:**
+- Catches `mqtt::exception` and logs errors; does not throw or crash
+
+### `void close_mqtt_conn()`
+
+Cleanly disconnects from the MQTT broker and cleans up resources.
+
+**Behavior:**
+- Checks if the client is connected before attempting disconnect
+- Calls `mqtt_client->disconnect()` and waits for completion
+- Resets `mqtt_client` and `mqtt_cb` shared pointers to allow object destruction
+- Logs disconnection and cleanup status
+
+**Error Handling:**
+- Catches `mqtt::exception` and logs errors
+- Continues cleanup even if errors occur
+
+### `bool open_device(const std::string& device_path, int baud_rate)`
+
+Opens and configures a serial port device.
+
+**Parameters:**
+- `device_path`: Path to the serial device (e.g., `"/dev/ttyUSB0"`)
+- `baud_rate`: Communication speed in bits per second (e.g., `115200`)
+
+**Returns:**
+- `true` if device opened successfully
+- `false` if an error occurs
+
+**Behavior:**
+- Calls `serial.openDevice()` with the provided path and baud rate
+- Checks if the returned value is 1 (success)
+- Logs success or error status
+
+### `bool is_device_open()`
+
+Queries the current state of the serial device.
+
+**Returns:**
+- `true` if the device is open
+- `false` otherwise
+
+### `void close_device()`
+
+Closes the serial port and releases resources.
+
+**Behavior:**
+- Calls `serial.closeDevice()`
+- Ensures the device is no longer accessible for reads/writes
+
+### `void write(const std::string& data)`
+
+Writes data to the serial device.
+
+**Behavior:**
+- Logs the write operation
+- Calls `serial.writeString()` with the data
+
+## MQTT Callback Handler
+
+### `class callback : public virtual mqtt::callback`
+
+A nested class that implements the Paho MQTT callback interface.
+
+**Method: `message_arrived(mqtt::const_message_ptr msg)`**
+
+- Invoked when a message arrives on a subscribed topic
+- Extracts the payload string via `msg->get_payload_str()`
+- Calls `parse_data()` to deserialize and publish the IMU message
+
+## Data Flow Architecture
+
+### Serial Data Path
+
+```
+Physical IMU Device
+         ↓
+Serial Port (e.g., /dev/ttyUSB0 @ 115200 baud)
+         ↓
+start_read() Background Thread
+         ↓
+serial.readString(buffer, 1000ms timeout)
+         ↓
+Accumulate into partial_buffer_
+         ↓
+Split on '\n' and Extract Complete Lines
+         ↓
+Sanitize (trim, strip garbage before '{')
+         ↓
+Validate JSON Structure (must have '{' and '}')
+         ↓
+parse_data(json_line)
+         ↓
+JSON Parse → sensor_msgs::msg::Imu
+         ↓
+publish_imu_data() → ROS Topic `imu_data`
+```
+
+### MQTT Data Path
+
+```
+MQTT Broker (tcp://localhost:1883)
+         ↓
+MQTT Async Client (mqtt_client)
+         ↓
+Topic Subscription (esp32/imu)
+         ↓
+MQTT Callback (message_arrived)
+         ↓
+parse_data(payload_string)
+         ↓
+JSON Parse → sensor_msgs::msg::Imu
+         ↓
+publish_imu_data() → ROS Topic `imu_data`
+```
+
+## Buffer Management & Message Reconstruction
+
+The `partial_buffer_` member implements a robust strategy for handling fragmented serial reads:
+
+1. **Accumulation**: Each serial read chunk is appended to `partial_buffer_`
+2. **Line Splitting**: Buffer is searched for newline delimiters
+3. **Validation**: Each line is checked for JSON structure (presence of `{` and `}`)
+4. **Sanitization**: Leading garbage (characters before `{`) is stripped
+5. **Incomplete Message Handling**: If a line lacks a closing brace, it's pushed back to the buffer and the loop waits for more data
+6. **Parse & Publish**: Complete JSON lines are parsed and published
+
+**Why This Matters:**
+- Serial reads may return fragments of a JSON message (e.g., `",\"gyro\":{...}"`)
+- Multiple messages can arrive in a single read
+- Buffering ensures robust handling of all edge cases
+
+## Error Handling & Recovery
+
+| Scenario | Behavior | Recovery |
+|----------|----------|----------|
+| Serial read timeout | Loop continues, checks `reading_` flag | Automatic retry on next iteration |
+| Incomplete JSON in buffer | Fragment is retained; waits for next read | No action needed; accumulation handles it |
+| JSON parse error | Error logged; thread continues listening | Move to next message |
+| Serial device disconnect | readString returns 0; loop continues | Application can reconnect via `open_device()` |
+| MQTT broker unreachable | Exception caught and logged | Retry via `mqtt_connect()` |
+| MQTT message error | Exception caught and logged | Connection remains for next message |
+
+## Thread Safety
+
+- **Atomic Flag**: `reading_` uses `std::atomic_bool` for lock-free thread signaling
+- **Publisher Thread-Safety**: rclcpp publishers are thread-safe; `parse_data()` can safely publish from reader thread
+- **Resource Cleanup**: `stop_read()` joins the thread before returning, ensuring clean shutdown
+- **No Shared Mutable State**: Aside from `reading_` and the publisher, thread does not access other class members during execution
+
+---
+
+## Integration with LifecycleManager
+
+The `LifecycleManager` orchestrates `HardwareInterface` lifecycle:
+
+| Lifecycle Phase | LifecycleManager Call | HardwareInterface Action |
+|---|---|---|
+| **Configure** | `hw_interface->open_device()` or `mqtt_configure()` | Open serial port or set up MQTT client |
+| **Activate** | `hw_interface->start_read()` or `mqtt_reader()` | Spawn reader thread or attach MQTT callbacks |
+| **Deactivate** | `hw_interface->stop_read()` or `close_mqtt_conn()` | Stop reader thread and join; disconnect MQTT |
+| **Cleanup** | `hw_interface->close_device()` | Release serial port |
+
+---
+
+## Usage Example
+
+### Direct Instantiation (Advanced)
+
+```cpp
+// Create an instance (normally managed by LifecycleManager)
+auto hw = std::make_shared<HardwareInterface>();
+
+// Serial workflow
+hw->open_device("/dev/ttyUSB0", 115200);
+hw->start_read();
+// ... node spins and publishes IMU data ...
+hw->stop_read();
+hw->close_device();
+
+// MQTT workflow
+hw->mqtt_configure();
+hw->mqtt_reader();
+// ... node spins and publishes IMU data ...
+hw->close_mqtt_conn();
+```
+
+## Design Patterns
+
+1. **Abstraction Pattern**: Encapsulates serial and MQTT complexity behind a unified interface
+2. **Thread Management**: Background reader thread with atomic signaling for clean shutdown
+3. **Buffer Accumulation**: Handles fragmented reads and multi-message batches robustly
+4. **Dual Backend Strategy**: Runtime selection of communication mode (serial or MQTT)
+5. **JSON Deserialization**: Uses industry-standard `nlohmann::json` for robust parsing
+
+## Dependencies
+
+- **rclcpp**: ROS2 C++ client library
+- **sensor_msgs**: ROS2 standard sensor message definitions
+- **paho-mqtt**: Paho C/C++ MQTT client library
+- **nlohmann/json**: Header-only JSON parsing library
+- **serialib**: Custom serial communication wrapper

doc/architecture/nodes/LifecycleManager.md

@@ -0,0 +1,215 @@
+# LifecycleManager (`assignments::two::g2_2025_lifecycle_node`)
+
+## Overview
+The `LifecycleManager` is the core lifecycle-aware node responsible for managing the IMU reader system's operational states and hardware communication. It orchestrates transitions between configuration, activation, and deactivation phases, abstracting the complexity of dual communication backends (serial and MQTT) into a unified interface.
+
+#### Implementation Details
+
+**Parameters**
+
+- **`device_path`** (string, default: "/dev/ttyUSB0"): Serial device path for hardware connection (e.g., USB serial adapter).
+- **`baudrate`** (int, default: 115200): Serial communication baud rate in bits per second.
+- **`comm_t`** (string, default: "serial"): Communication type selector—either "serial" or "mqtt" to determine which backend to use.
+
+**Constructor**
+```cpp
+LifecycleManager()
+```
+- Initializes ROS2 lifecycle node with name `lifecycle_manager`
+- Declares and reads configuration parameters: `device_path`, `baudrate`, and `comm_t`
+- Creates a shared instance of `HardwareInterface` for managing all hardware operations
+- Logs initialization status and readiness
+
+**Core Functions**
+
+**`CallbackReturn on_configure(const State&)`**
+- Enters the *Unconfigured* → *Inactive* transition
+- Checks the `comm_t` parameter to route initialization:
+  - **MQTT mode**: Calls `hw_interface->mqtt_configure()` to set up the MQTT client and broker connection
+  - **Serial mode**: Calls `hw_interface->open_device(device_path_, baudrate_)` to open and configure the serial port
+- Returns `SUCCESS` if device initialization succeeds, `FAILURE` if serial/MQTT setup fails
+- Logs configuration status and any errors
+- Example test code (currently commented) demonstrates direct JSON parsing for validation
+
+**`CallbackReturn on_activate(const State&)`**
+- Enters the *Inactive* → *Active* transition
+- Checks the `comm_t` parameter to start the appropriate reader:
+  - **MQTT mode**: Calls `hw_interface->mqtt_reader()` to attach MQTT callbacks and begin receiving messages
+  - **Serial mode**: Calls `hw_interface->start_read()` to spawn a background thread that continuously reads from the serial device
+- Returns `SUCCESS` after reader startup
+- Logs activation status and selected communication type
+
+**`CallbackReturn on_deactivate(const State&)`**
+- Enters the *Active* → *Inactive* transition
+- Checks the `comm_t` parameter to cleanly stop operations:
+  - **MQTT mode**: Calls `hw_interface->close_mqtt_conn()` to disconnect from the broker and clean up resources
+  - **Serial mode**:
+    - Verifies device state with `hw_interface->is_device_open()`
+    - Calls `hw_interface->stop_read()` to signal the reader thread to exit and joins it
+    - Calls `hw_interface->close_device()` to release the serial port
+- Returns `SUCCESS` after cleanup completes
+- Logs deactivation and resource release
+
+**`CallbackReturn on_shutdown(const State&)`**
+- Enters the *Inactive* → *Finalized* transition
+- Performs final shutdown logging
+- Returns `SUCCESS`
+
+**`CallbackReturn on_cleanup(const State&)`**
+- Called during error recovery or explicit cleanup commands
+- Performs resource cleanup and state logging
+- Returns `SUCCESS`
+
+
+## Communication Architecture
+
+### Dual Backend Support
+
+The `LifecycleManager` provides a flexible, pluggable communication architecture via the `comm_t` parameter:
+
+#### Serial Communication Path
+1. **Configuration Phase** (`on_configure`):
+   - Opens the serial device at the path specified by `device_path` and baudrate
+   - Validates device readiness
+
+2. **Activation Phase** (`on_activate`):
+   - Spawns a background reader thread via `hw_interface->start_read()`
+   - Thread continuously polls the serial device with a timeout
+   - Reads are accumulated in a partial buffer, split on newline, and parsed as JSON
+   - Each valid JSON IMU payload is parsed into a `sensor_msgs::msg::Imu` and published to the ROS topic `imu/data`
+
+3. **Deactivation Phase** (`on_deactivate`):
+   - Signals the reader thread to stop via atomic flag
+   - Joins the thread to ensure clean termination
+   - Closes the serial device
+
+#### MQTT Communication Path
+1. **Configuration Phase** (`on_configure`):
+   - Creates a persistent MQTT async client pointing to the broker at `SERVER_ADDRESS` (default: `tcp://localhost:1883`)
+   - Initializes MQTT callback infrastructure
+
+2. **Activation Phase** (`on_activate`):
+   - Attaches MQTT callbacks to the client
+   - Subscribes to the topic specified by `TOPIC` (default: `esp32/imu`)
+   - The async client runs background threads to receive messages
+
+3. **Deactivation Phase** (`on_deactivate`):
+   - Disconnects from the broker
+   - Cleans up MQTT client and callback resources
+
+## Lifecycle Commands
+
+To interact with the `LifecycleManager` from the command line, use the following ROS2 lifecycle service calls:
+
+```bash
+# List current lifecycle state
+ros2 lifecycle list /LifecycleManager
+
+# Transition: UNCONFIGURED -> INACTIVE
+ros2 lifecycle set /LifecycleManager configure
+
+# Transition: INACTIVE -> UNCONFIGURED
+ros2 lifecycle set /LifecycleManager cleanup
+
+# Transition: INACTIVE -> ACTIVE
+ros2 lifecycle set /LifecycleManager activate
+
+# Transition: ACTIVE -> INACTIVE
+ros2 lifecycle set /LifecycleManager deactivate
+
+# Transition: INACTIVE -> FINALIZED
+ros2 lifecycle set /LifecycleManager shutdown
+```
+![img](https://design.ros2.org/img/node_lifecycle/life_cycle_sm.png)
+
+## Data Flow
+
+### Serial Data Flow
+```
+Hardware Device
+      ↓
+Serial Port (/dev/ttyUSB0)
+      ↓
+Background Reader Thread (start_read)
+      ↓
+Partial Buffer Accumulation
+      ↓
+JSON Line Extraction & Sanitization
+      ↓
+parse_data() ← Deserializes JSON to sensor_msgs::msg::Imu
+      ↓
+imu_publisher → ROS2 Topic (`imu_data`)
+```
+
+### MQTT Data Flow
+```
+MQTT Broker (localhost:1883)
+      ↓
+MQTT Async Client (Background Thread)
+      ↓
+Subscription to Topic (esp32/imu)
+      ↓
+MQTT Callback Handler
+      ↓
+parse_data() ← Deserializes JSON to sensor_msgs::msg::Imu
+      ↓
+imu_publisher → ROS2 Topic (`imu_data`)
+```
+
+## Error Handling
+
+- **Serial Device Failures**: If `open_device()` fails during configuration, `on_configure()` returns `FAILURE` and the system remains in the `UNCONFIGURED` state
+- **Communication Errors**: JSON parse errors from invalid payloads are caught and logged without crashing the node; the reader continues listening for the next message
+- **Thread Safety**: The reader thread uses an atomic flag (`reading_`) for clean stop signaling and ensures all resources are properly joined before returning from `on_deactivate()`
+
+## Design Patterns
+
+1. **Strategy Pattern**: The `comm_t` parameter enables runtime selection of communication backend without changing node code
+2. **Lifecycle Pattern**: Follows ROS2 managed node pattern for predictable initialization, startup, and shutdown sequences
+3. **Thread Safety**: Atomic flags and resource cleanup ensure the reader thread can be safely started and stopped
+4. **Buffer Accumulation**: Partial message buffering handles fragmented serial reads and ensures complete JSON objects are parsed
+
+## Integration with HardwareInterface
+
+The `LifecycleManager` delegates all hardware operations to the `HardwareInterface` class:
+
+| Operation | Method | Lifecycle Phase |
+|-----------|--------|-----------------|
+| Open serial device | `open_device(path, baud)` | on_configure |
+| Start reading | `start_read()` | on_activate |
+| Stop reading | `stop_read()` | on_deactivate |
+| Close serial device | `close_device()` | on_deactivate |
+| Configure MQTT | `mqtt_configure()` | on_configure |
+| Start MQTT reading | `mqtt_reader()` | on_activate |
+| Close MQTT connection | `close_mqtt_conn()` | on_deactivate |
+| Parse JSON payload | `parse_data(json_string)` | on_activate (continuous) |
+| Publish IMU message | `publish_imu_data(imu_msg)` | on_activate (continuous) |
+
+## Usage Example
+
+```bash
+# Launch the node with serial communication at /dev/ttyUSB0, 115200 baud
+ros2 run g2_2025_imu_reader_pkg g2_2025_lifecycle_node \
+  --ros-args \
+  -p device_path:=/dev/ttyUSB0 \
+  -p baudrate:=115200 \
+  -p comm_t:=serial
+
+# Alternatively, launch with MQTT communication
+ros2 run g2_2025_imu_reader_pkg g2_2025_lifecycle_node \
+  --ros-args \
+  -p comm_t:=mqtt
+
+# In another terminal, configure and activate the lifecycle
+ros2 lifecycle set /LifecycleManager configure
+ros2 lifecycle set /LifecycleManager activate
+
+# Subscribe to published IMU data
+ros2 topic echo /imu_data
+
+# Deactivate and shutdown
+ros2 lifecycle set /LifecycleManager deactivate
+ros2 lifecycle set /LifecycleManager shutdown
+```
+
+---

doc/installation/installation.md

@@ -10,6 +10,22 @@
 - Colcon build tool
 - Docker compose
 
+### Paho MQTT library
+
+For this project the Paho MQTT library is needed, which can be built with the following commands:
+
+```bash
+git clone https://github.com/eclipse/paho.mqtt.cpp
+cd paho.mqtt.cpp
+git co v1.5.4
+
+git submodule init
+git submodule update
+
+cmake -Bbuild -H. -DPAHO_WITH_MQTT_C=ON -DPAHO_BUILD_EXAMPLES=ON
+sudo cmake --build build/ --target install
+```
+
 ### Clone the Repository
 
 ```bash
@@ -38,6 +54,22 @@ You can configure specific database settings in the `docker-compose.yaml` in the
 
 ### Start the IMU Reader program
 ```bash
-ros2 launch g2_2025_imu_reader_pkg imu_reader.launch.xml
+# For Serial:
+ros2 launch g2_2025_imu_reader_pkg serial.launch.xml
+
+# For MQTT:
+ros2 launch g2_2025_imu_reader_pkg mqtt.launch.xml
 ```
 To change parameters when using the launch file it will need to be edited in the `src/g2_2025_imu_reader_pkg/launch` folder. All parameters are already added to this document and thus only the values will need to be changed
+
+### Use the Lifecycle Node
+
+To setup the lifecycle node the following commands can be used. They must be used in this order.
+```bash
+ros2 lifecycle set /LifecycleManager configure
+ros2 lifecycle set /LifecycleManager cleanup
+ros2 lifecycle set /LifecycleManager activate
+ros2 lifecycle set /LifecycleManager deactivate
+ros2 lifecycle set /LifecycleManager shutdown
+```
+![img](https://design.ros2.org/img/node_lifecycle/life_cycle_sm.png)

doc/tests/LifecycleManager.md

@@ -0,0 +1,229 @@
+# LifecycleManager Unit Tests
+
+Unit tests for `LifecycleManager` are implemented in `src/g2_2025_imu_reader_pkg/test/LifecycleManager.test.cpp` using Google Test and ROS2 lifecycle test utilities. The tests are designed to validate all lifecycle state transitions, parameter handling, and hardware integration without requiring actual hardware or MQTT broker connectivity.
+
+## Test Cases
+
+### 1. ConstructorTest
+
+**Description:** Verifies that LifecycleManager can be instantiated without crashing and parameters are correctly declared.
+
+- **Test Action:** Create LifecycleManager instance with default parameters
+- **Expected Result:** Instance created successfully; parameters `device_path`, `baudrate`, and `comm_t` are registered with their defaults
+
+---
+
+### 2. ParameterDeclarationTest
+
+**Description:** Tests that all required parameters are declared during construction with correct default values.
+
+- **Test Action:**
+  - Create LifecycleManager
+  - Query parameters: `device_path`, `baudrate`, `comm_t`
+- **Expected Result:**
+  - `device_path` defaults to `"/dev/ttyUSB0"`
+  - `baudrate` defaults to `115200`
+  - `comm_t` defaults to `"serial"`
+
+---
+
+### 3. ParameterRuntimeReadTest
+
+**Description:** Verifies parameters can be read at runtime and affect behavior.
+
+- **Test Action:**
+  - Set parameters via ROS2 parameter API: `device_path="/dev/ttyACM0"`, `comm_t="mqtt"`
+  - Verify LifecycleManager reads the updated values
+- **Expected Result:** Parameters are correctly read and stored in member variables
+
+---
+
+### 4. InitialStateTest
+
+**Description:** Tests that the node starts in the `UNCONFIGURED` state.
+
+- **Test Action:** Create LifecycleManager and check lifecycle state
+- **Expected Result:** Node is in `UNCONFIGURED` state
+
+---
+
+### 5. ConfigureSerialModeTest
+
+**Description:** Tests the `on_configure` callback in serial communication mode.
+
+- **Test Action:**
+  - Set `comm_t` parameter to `"serial"`
+  - Call `on_configure()` with valid device path (e.g., `/dev/null` for testing)
+- **Expected Result:**
+  - Transition succeeds
+  - Node moves to `INACTIVE` state
+  - `HardwareInterface::open_device()` is called with correct parameters
+
+---
+
+### 6. ConfigureMQTTModeTest
+
+**Description:** Tests the `on_configure` callback in MQTT communication mode.
+
+- **Test Action:**
+  - Set `comm_t` parameter to `"mqtt"`
+  - Call `on_configure()`
+- **Expected Result:**
+  - Transition succeeds
+  - Node moves to `INACTIVE` state
+  - `HardwareInterface::mqtt_configure()` is called
+
+---
+
+### 7. ConfigureSerialFailureTest
+
+**Description:** Tests graceful failure when serial device cannot be opened.
+
+- **Test Action:**
+  - Set `device_path` to non-existent path (e.g., `/dev/invalid_device`)
+  - Set `comm_t` to `"serial"`
+  - Call `on_configure()`
+- **Expected Result:**
+  - Transition handled gracefully (node doesn't crash)
+  - Error logging occurs
+
+---
+
+### 8. DeactivateSerialModeTest
+
+**Description:** Tests the `on_deactivate` callback in serial communication mode.
+
+- **Test Action:**
+  - Configure to `INACTIVE` state in serial mode
+  - Call `on_deactivate()`
+- **Expected Result:**
+  - Transition handled gracefully
+  - Resources are properly released
+
+---
+
+### 9. ResourceCleanupTest
+
+**Description:** Tests that all resources are properly cleaned up on deactivation and shutdown.
+
+- **Test Action:**
+  - Configure node with serial settings
+  - Let node go out of scope
+  - Verify no crashes or resource leaks
+- **Expected Result:**
+  - No memory leaks
+  - File descriptors are closed
+  - No segmentation faults on cleanup
+
+---
+
+### 10. ErrorLoggingTest
+
+**Description:** Tests that error handling works during configuration attempts.
+
+- **Test Action:**
+  - Set invalid device path and attempt configuration
+  - Verify error is handled gracefully
+- **Expected Result:**
+  - Node doesn't crash on error
+  - Error logging occurs
+
+---
+
+### 11. HardwareInterfaceIntegrationTest
+
+**Description:** Tests the complete integration between LifecycleManager and HardwareInterface.
+
+- **Test Action:**
+  - Create LifecycleManager instance
+  - Verify HardwareInterface instance is created and accessible
+  - Verify we can call HardwareInterface methods
+- **Expected Result:**
+  - HardwareInterface is properly initialized
+  - No segmentation faults when accessing interface methods
+
+---
+
+### 12. DevicePathParameterTest
+
+**Description:** Tests that device_path parameter correctly controls serial device selection.
+
+- **Test Action:**
+  - Set `device_path` to `/dev/null`
+  - Call `on_configure()` in serial mode
+  - Verify correct device path is used
+- **Expected Result:**
+  - Configuration succeeds with correct device path
+
+---
+
+### 13. BaudRateParameterTest
+
+**Description:** Tests that baudrate parameter is correctly configured.
+
+- **Test Action:**
+  - Set `baudrate` to valid value (e.g., 115200)
+  - Call `on_configure()` in serial mode
+- **Expected Result:**
+  - Correct baud rate is passed to the hardware interface
+
+---
+
+### 14. ParameterUpdateBehaviorTest
+
+**Description:** Tests that parameter changes are respected across state transitions.
+
+- **Test Action:**
+  - Set `comm_t` to `"serial"`, configure
+  - Deactivate and transition back to UNCONFIGURED
+  - Change `comm_t` to `"mqtt"`
+  - Re-configure with new communication mode
+- **Expected Result:**
+  - Communication mode switches work correctly
+  - Parameter changes are respected
+
+---
+
+## Test Organization
+
+Tests are organized into logical groups:
+
+1. **Construction & Initialization** (Tests 1-3): Basic object creation and parameter setup
+2. **State Transitions & Configuration** (Tests 4-7): Lifecycle callbacks and state validation
+3. **Parameter Validation** (Tests 12-13): Parameter binding and influence on behavior
+4. **Complete Sequences** (Test 14): Parameter switching across state transitions
+5. **Resource & Thread Safety** (Tests 8-9): Resource cleanup and safe deactivation
+6. **Error Handling & Integration** (Tests 10-11): Error resilience and component integration
+
+---
+
+## Test Execution
+
+### Run All Tests
+
+```bash
+# From workspace root
+colcon test --packages-select g2_2025_imu_reader_pkg
+```
+
+### Run Specific Test Suite
+
+```bash
+# Run only LifecycleManager tests
+colcon test --packages-select g2_2025_imu_reader_pkg --ctest-args -R "LifecycleManager"
+```
+
+### Run with Verbose Output
+
+```bash
+colcon test --packages-select g2_2025_imu_reader_pkg --ctest-args --verbose
+```
+
+### Run Tests Directly
+
+```bash
+# From workspace root
+./build/g2_2025_imu_reader_pkg/g2_2025_imu_reader_pkg_test_lifecycle_manager
+```
+
+---

src/IMU/main/mpu6886.c

@@ -291,6 +291,9 @@ void app_main(void)
     }
 
     init_button();
+    gpio_reset_pin(LED_GPIO);
+    gpio_set_direction(LED_GPIO, GPIO_MODE_OUTPUT);
+
     mpu6886_t mpu;
     mpu.i2c_port = I2C_NUM_0;
     mpu.address = MPU6886_ADDR;
@@ -311,11 +314,13 @@ void app_main(void)
             wifi_init();
             mqtt_app_start();
             ESP_LOGI("BOOT", "Boot button pressed: starting MQTT mode");
+            gpio_set_level(LED_GPIO, 1);
             toggle_completed = true;
         } else if (!mqtt_toggle && !toggle_completed && wifi_initialized) {
             mqtt_app_stop();
             wifi_deinit();
             ESP_LOGI("BOOT", "Boot button not pressed: starting serial-only mode");
+            gpio_set_level(LED_GPIO, 0);
             toggle_completed = true;
         }
         mpu6886_read_accel(&mpu, &accel);

src/IMU/main/mpu6886.h

@@ -26,6 +26,7 @@
 #define I2C_MASTER_TIMEOUT_MS       1000
 
 #define BOOT_BUTTON_GPIO 0 // GPIO number for boot mode selection button
+#define LED_GPIO 33         // GPIO number for onboard LED
 
 #define MPU6886_ADDR 0x68
 
@@ -71,7 +72,7 @@ typedef struct {
     vec3_t accel_offset;
 } mpu6886_t;
 
-bool mqtt_toggle = false;
+bool mqtt_toggle = true;
 bool toggle_completed = false;
 bool wifi_initialized = false;
 

src/IMU/sdkconfig

@@ -448,8 +448,6 @@ CONFIG_I2C_MASTER_SDA=21
 CONFIG_I2C_MASTER_FREQUENCY=100000
 # end of I2C Master Configuration
 
-CONFIG_ENV_MQTT_ENABLED=y
-
 #
 # MQTT Configuration
 #

src/g2_2025_imu_reader_pkg/CMakeLists.txt

@@ -8,13 +8,21 @@ endif()
 # external packages
 include(FetchContent)
 
-fetchcontent_declare(
+FetchContent_Declare(
     tomlplusplus
     GIT_REPOSITORY https://github.com/marzer/tomlplusplus.git
     GIT_TAG v3.4.0
 )
 
-fetchcontent_makeavailable(tomlplusplus)
+FetchContent_MakeAvailable(tomlplusplus)
+
+FetchContent_Declare(
+    nlohmann_json
+    GIT_REPOSITORY https://github.com/nlohmann/json.git
+    GIT_TAG v3.12.0
+)
+
+FetchContent_MakeAvailable(nlohmann_json)
 
 # find dependencies
 find_package(ament_cmake REQUIRED)
@@ -22,6 +30,7 @@ find_package(rclcpp REQUIRED)
 find_package(rclcpp_action REQUIRED)
 find_package(std_msgs REQUIRED)
 find_package(sensor_msgs REQUIRED)
+find_package(rclcpp_lifecycle REQUIRED)
 
 add_executable(g2_2025_imu_database_writer_node
     src/g2_2025_imu_database_writer_node/Main.cpp
@@ -29,6 +38,7 @@ add_executable(g2_2025_imu_database_writer_node
     src/config/ConfigManager.cpp
     src/g2_2025_imu_database_writer_node/nodes/IMUDatabaseWriter.cpp
 )
+
 target_include_directories(g2_2025_imu_database_writer_node PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}/src
     ${CMAKE_CURRENT_SOURCE_DIR}/src/g2_2025_imu_database_writer_node
@@ -36,12 +46,39 @@ target_include_directories(g2_2025_imu_database_writer_node PRIVATE
 ament_target_dependencies(g2_2025_imu_database_writer_node rclcpp sensor_msgs)
 target_link_libraries(g2_2025_imu_database_writer_node pqxx pq tomlplusplus::tomlplusplus)
 
+add_executable(g2_2025_lifecycle_node
+    src/g2_2025_lifecycle_node/Main.cpp
+    src/g2_2025_lifecycle_node/nodes/HardwareInterface.cpp
+    src/g2_2025_lifecycle_node/nodes/LifecycleManager.cpp
+    lib/serialib.cpp
+)
+
+target_include_directories(g2_2025_lifecycle_node PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/src
+    ${CMAKE_CURRENT_SOURCE_DIR}/lib
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/g2_2025_lifecycle_node
+)
+ament_target_dependencies(g2_2025_lifecycle_node rclcpp rclcpp_lifecycle std_msgs sensor_msgs)
+
+target_link_libraries(g2_2025_lifecycle_node
+  paho-mqttpp3
+  paho-mqtt3c
+  nlohmann_json::nlohmann_json
+)
+
 install(
     TARGETS
         g2_2025_imu_database_writer_node
+        g2_2025_lifecycle_node
     DESTINATION lib/${PROJECT_NAME}
 )
 
+install(
+    DIRECTORY launch
+    DESTINATION share/${PROJECT_NAME}/
+)
+set_target_properties(g2_2025_lifecycle_node PROPERTIES INSTALL_RPATH "/usr/local/lib")
+
 if(BUILD_TESTING)
   find_package(ament_cmake_gtest REQUIRED)
 
@@ -95,6 +132,30 @@ if(BUILD_TESTING)
     pqxx pq tomlplusplus::tomlplusplus
   )
 
+  ament_add_gtest(${PROJECT_NAME}_test_lifecycle_manager
+    test/LifecycleManager.test.cpp
+    src/g2_2025_lifecycle_node/nodes/LifecycleManager.cpp
+    src/g2_2025_lifecycle_node/nodes/HardwareInterface.cpp
+    lib/serialib.cpp
+  )
+  target_include_directories(${PROJECT_NAME}_test_lifecycle_manager PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/src
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/g2_2025_lifecycle_node
+    ${CMAKE_CURRENT_SOURCE_DIR}/lib
+  )
+  ament_target_dependencies(${PROJECT_NAME}_test_lifecycle_manager
+    rclcpp
+    rclcpp_lifecycle
+    std_msgs
+    sensor_msgs
+  )
+  target_link_libraries(${PROJECT_NAME}_test_lifecycle_manager
+    paho-mqttpp3
+    paho-mqtt3c
+    nlohmann_json::nlohmann_json
+  )
+  set_target_properties(${PROJECT_NAME}_test_lifecycle_manager PROPERTIES INSTALL_RPATH "/usr/local/lib")
+
   # Add Python integration tests
   #   find_package(ament_cmake_pytest REQUIRED)
   #   ament_add_pytest_test(${PROJECT_NAME}_integration_test test/test_integration_system.py

src/g2_2025_imu_reader_pkg/launch/mqtt.launch.xml

@@ -0,0 +1,6 @@
+<launch>
+    <node pkg="g2_2025_imu_reader_pkg" exec="g2_2025_imu_database_writer_node"/>
+    <node pkg="g2_2025_imu_reader_pkg" exec="g2_2025_lifecycle_node">
+        <param name="comm_t" value="mqtt"/>
+    </node>
+</launch>

src/g2_2025_imu_reader_pkg/launch/serial.launch.xml

@@ -0,0 +1,8 @@
+<launch>
+    <node pkg="g2_2025_imu_reader_pkg" exec="g2_2025_imu_database_writer_node"/>
+    <node pkg="g2_2025_imu_reader_pkg" exec="g2_2025_lifecycle_node">
+        <param name="device_path" value="/dev/ttyUSB0"/>
+        <param name="baudrate" value="115200"/>
+        <param name="comm_t" value="serial"/>
+    </node>
+</launch>

src/g2_2025_imu_reader_pkg/lib/serialib.h

@@ -0,0 +1,270 @@
+/*!
+\file    serialib.h
+\brief   Header file of the class serialib. This class is used for communication over a serial device.
+\author  Philippe Lucidarme (University of Angers)
+\version 2.0
+\date    december the 27th of 2019
+This Serial library is used to communicate through serial port.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM,
+DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+This is a licence-free software, it can be used by anyone who try to build a better world.
+*/
+
+
+#ifndef SERIALIB_H
+#define SERIALIB_H
+
+#if defined(__CYGWIN__)
+    // This is Cygwin special case
+    #include <sys/time.h>
+#endif
+
+// Include for windows
+#if defined (_WIN32) || defined (_WIN64)
+#if defined(__GNUC__)
+    // This is MinGW special case
+    #include <sys/time.h>
+#else
+    // sys/time.h does not exist on "actual" Windows
+    #define NO_POSIX_TIME
+#endif
+    // Accessing to the serial port under Windows
+    #include <windows.h>
+#endif
+
+// Include for Linux
+#if defined (__linux__) || defined(__APPLE__)
+    #include <stdlib.h>
+    #include <sys/types.h>
+    #include <sys/shm.h>
+    #include <termios.h>
+    #include <string.h>
+    #include <iostream>
+    #include <sys/time.h>
+    // File control definitions
+    #include <fcntl.h>
+    #include <unistd.h>
+    #include <sys/ioctl.h>
+#endif
+
+/*! To avoid unused parameters */
+#define UNUSED(x) (void)(x)
+
+/**
+ * number of serial data bits
+ */
+enum SerialDataBits {
+    SERIAL_DATABITS_5, /**< 5 databits */
+    SERIAL_DATABITS_6, /**< 6 databits */
+    SERIAL_DATABITS_7, /**< 7 databits */
+    SERIAL_DATABITS_8,  /**< 8 databits */
+    SERIAL_DATABITS_16,  /**< 16 databits */
+};
+
+/**
+ * number of serial stop bits
+ */
+enum SerialStopBits {
+    SERIAL_STOPBITS_1, /**< 1 stop bit */
+    SERIAL_STOPBITS_1_5, /**< 1.5 stop bits */
+    SERIAL_STOPBITS_2, /**< 2 stop bits */
+};
+
+/**
+ * type of serial parity bits
+ */
+enum SerialParity {
+    SERIAL_PARITY_NONE, /**< no parity bit */
+    SERIAL_PARITY_EVEN, /**< even parity bit */
+    SERIAL_PARITY_ODD, /**< odd parity bit */
+    SERIAL_PARITY_MARK, /**< mark parity */
+    SERIAL_PARITY_SPACE /**< space bit */
+};
+
+/*!  \class     serialib
+     \brief     This class is used for communication over a serial device.
+*/
+class serialib
+{
+public:
+
+    //_____________________________________
+    // ::: Constructors and destructors :::
+
+
+
+    // Constructor of the class
+    serialib    ();
+
+    // Destructor
+    ~serialib   ();
+
+
+
+    //_________________________________________
+    // ::: Configuration and initialization :::
+
+
+    // Open a device
+    char openDevice(const char *Device, const unsigned int Bauds,
+                    SerialDataBits Databits = SERIAL_DATABITS_8,
+                    SerialParity Parity = SERIAL_PARITY_NONE,
+                    SerialStopBits Stopbits = SERIAL_STOPBITS_1);
+
+    // Check device opening state
+    bool isDeviceOpen();
+
+    // Close the current device
+    void    closeDevice();
+
+
+
+
+    //___________________________________________
+    // ::: Read/Write operation on characters :::
+
+
+    // Write a char
+    int     writeChar   (char);
+
+    // Read a char (with timeout)
+    int     readChar    (char *pByte,const unsigned int timeOut_ms=0);
+
+
+
+
+    //________________________________________
+    // ::: Read/Write operation on strings :::
+
+
+    // Write a string
+    int     writeString (const char *String);
+
+    // Read a string (with timeout)
+    int     readString  (   char *receivedString,
+                            char finalChar,
+                            unsigned int maxNbBytes,
+                            const unsigned int timeOut_ms=0);
+
+
+
+    // _____________________________________
+    // ::: Read/Write operation on bytes :::
+
+
+    // Write an array of bytes
+    int     writeBytes(const void *Buffer, const unsigned int NbBytes, unsigned int *NbBytesWritten);
+    int     writeBytes  (const void *Buffer, const unsigned int NbBytes);
+
+    // Read an array of byte (with timeout)
+    int     readBytes   (void *buffer,unsigned int maxNbBytes,const unsigned int timeOut_ms=0, unsigned int sleepDuration_us=100);
+
+
+
+
+    // _________________________
+    // ::: Special operation :::
+
+
+    // Empty the received buffer
+    char    flushReceiver();
+
+    // Return the number of bytes in the received buffer
+    int     available();
+
+
+
+
+    // _________________________
+    // ::: Access to IO bits :::
+
+
+    // Set CTR status (Data Terminal Ready, pin 4)
+    bool    DTR(bool status);
+    bool    setDTR();
+    bool    clearDTR();
+
+    // Set RTS status (Request To Send, pin 7)
+    bool    RTS(bool status);
+    bool    setRTS();
+    bool    clearRTS();
+
+    // Get RI status (Ring Indicator, pin 9)
+    bool    isRI();
+
+    // Get DCD status (Data Carrier Detect, pin 1)
+    bool    isDCD();
+
+    // Get CTS status (Clear To Send, pin 8)
+    bool    isCTS();
+
+    // Get DSR status (Data Set Ready, pin 9)
+    bool    isDSR();
+
+    // Get RTS status (Request To Send, pin 7)
+    bool    isRTS();
+
+    // Get CTR status (Data Terminal Ready, pin 4)
+    bool    isDTR();
+
+
+private:
+    // Read a string (no timeout)
+    int             readStringNoTimeOut  (char *String,char FinalChar,unsigned int MaxNbBytes);
+
+    // Current DTR and RTS state (can't be read on WIndows)
+    bool            currentStateRTS;
+    bool            currentStateDTR;
+
+
+
+
+
+#if defined (_WIN32) || defined( _WIN64)
+    // Handle on serial device
+    HANDLE          hSerial;
+    // For setting serial port timeouts
+    COMMTIMEOUTS    timeouts;
+#endif
+#if defined (__linux__) || defined(__APPLE__)
+    int             fd;
+#endif
+
+};
+
+
+
+/*!  \class     timeOut
+     \brief     This class can manage a timer which is used as a timeout.
+   */
+// Class timeOut
+class timeOut
+{
+public:
+
+    // Constructor
+    timeOut();
+
+    // Init the timer
+    void                initTimer();
+
+    // Return the elapsed time since initialization
+    unsigned long int   elapsedTime_ms();
+
+private:
+#if defined (NO_POSIX_TIME)
+    // Used to store the previous time (for computing timeout)
+    LONGLONG       counterFrequency;
+    LONGLONG       previousTime;
+#else
+    // Used to store the previous time (for computing timeout)
+    struct timeval      previousTime;
+#endif
+};
+
+#endif // serialib_H

src/g2_2025_imu_reader_pkg/src/g2_2025_lifecycle_node/Main.cpp

@@ -0,0 +1,23 @@
+/* main.cpp
+ * Entry point for lifecycle node
+ *
+ * Reviewed by: <x>
+ * Changelog:
+ * [23-09-2025] Wessel T: Simplified main.cpp to entry point only
+ */
+
+#include "rclcpp/rclcpp.hpp"
+
+#include "nodes/HardwareInterface.hpp"
+#include "nodes/LifecycleManager.hpp"
+
+int main(int argc, char *argv[]) {
+    rclcpp::init(argc, argv);
+
+    auto node = std::make_shared<assignments::two::g2_2025_lifecycle_node::LifecycleManager>();
+
+    rclcpp::spin(node->get_node_base_interface());
+    rclcpp::shutdown();
+
+    return 0;
+}

src/g2_2025_imu_reader_pkg/src/g2_2025_lifecycle_node/nodes/HardwareInterface.cpp

@@ -0,0 +1,218 @@
+#include "HardwareInterface.hpp"
+
+namespace assignments::two::g2_2025_lifecycle_node {
+
+HardwareInterface::HardwareInterface(MQTTParameters mqtt_config)
+: Node("HardwareInterface")
+, mqtt_config_(mqtt_config)
+{
+    RCLCPP_INFO(this->get_logger(), "created HardwareInterface node");
+
+    imu_publisher_ = this->create_publisher<sensor_msgs::msg::Imu>("imu_data", 10);
+    RCLCPP_INFO(this->get_logger(), "created IMU Publisher on topic 'imu_data'");
+}
+
+HardwareInterface::~HardwareInterface() {
+    uart_stop_read();
+
+    if (uart_device_is_open()) {
+        uart_close_device();
+    }
+
+    mqtt_close_connection();
+}
+
+void HardwareInterface::parse_and_publish_imu_data(const std::string& data) {
+    try {
+        auto json_data = nlohmann::json::parse(data);
+        auto imu_msg = std::make_shared<sensor_msgs::msg::Imu>();
+
+        imu_msg->header.stamp = this->now();
+        imu_msg->header.frame_id = "imu_link";
+
+        // angular velocity
+        if (json_data.contains("accel") && json_data["accel"].is_object()) {
+            imu_msg->linear_acceleration.x = json_data["accel"].value("x", 0.0);
+            imu_msg->linear_acceleration.y = json_data["accel"].value("y", 0.0);
+            imu_msg->linear_acceleration.z = json_data["accel"].value("z", 0.0);
+        }
+
+        // linear acceleration
+        if (json_data.contains("gyro") && json_data["gyro"].is_object()) {
+            imu_msg->angular_velocity.x = json_data["gyro"].value("x", 0.0);
+            imu_msg->angular_velocity.y = json_data["gyro"].value("y", 0.0);
+            imu_msg->angular_velocity.z = json_data["gyro"].value("z", 0.0);
+        }
+
+        RCLCPP_INFO(this->get_logger(),
+            "Publishing IMU Data - Accel: [%.3f, %.3f, %.3f], Gyro: [%.3f, %.3f, %.3f]",
+            imu_msg->linear_acceleration.x, imu_msg->linear_acceleration.y, imu_msg->linear_acceleration.z,
+            imu_msg->angular_velocity.x, imu_msg->angular_velocity.y, imu_msg->angular_velocity.z
+        );
+
+        imu_publisher_->publish(*imu_msg);
+    } catch (const nlohmann::json::exception& e) {
+        RCLCPP_ERROR(this->get_logger(), "JSON parsing error: %s", e.what());
+    }
+}
+
+void HardwareInterface::uart_start_read() {
+    if (uart_reading_.load()) {
+        return;
+    }
+
+    uart_reading_.store(true);
+
+    uart_read_thread_ = std::thread([this]() {
+        char buffer[116];
+        RCLCPP_INFO(this->get_logger(), "reader thread started");
+
+        while (uart_reading_.load()) {
+            int ret = serial_.readString(buffer, '\n', sizeof(buffer), 1000);
+            if (ret > 0) {
+                RCLCPP_INFO(this->get_logger(), "Received buffer: %s", buffer);
+                parse_and_publish_imu_data(buffer);
+            }
+        }
+
+        RCLCPP_INFO(this->get_logger(), "reader thread exiting");
+    });
+}
+
+void HardwareInterface::uart_stop_read() {
+    if (!uart_reading_.load()) return;
+    uart_reading_.store(false);
+
+    if (uart_read_thread_.joinable()) {
+        uart_read_thread_.join();
+    }
+}
+
+bool HardwareInterface::uart_open_device(const std::string& device_path, int baud_rate) {
+    char errorOpening = serial_.openDevice(device_path.c_str(), baud_rate);
+
+    if (errorOpening != 1) {
+        RCLCPP_ERROR(this->get_logger(), "Error opening serial_ port: %d", errorOpening);
+        return false;
+    }
+
+    RCLCPP_INFO(this->get_logger(), "serial_ port opened successfully.");
+    return true;
+}
+
+bool HardwareInterface::uart_device_is_open() {
+    return serial_.isDeviceOpen();
+}
+
+void HardwareInterface::uart_close_device() {
+    serial_.closeDevice();
+}
+
+void HardwareInterface::mqtt_message_callback(
+    const std::string& topic,
+    const std::string& payload,
+    HardwareInterface* self
+) {
+    if (self) {
+        RCLCPP_INFO(self->get_logger(), "Message received on topic %s: %s", topic.c_str(), payload.c_str());
+
+        self->parse_and_publish_imu_data(payload);
+    }
+}
+
+void HardwareInterface::mqtt_configure() {
+    try {
+        RCLCPP_INFO(this->get_logger(), "Creating MQTT client with server: %s, client_id: %s",
+            mqtt_config_.server_address.c_str(), mqtt_config_.client_id.c_str()
+        );
+
+        // Create client with basic constructor (no persistence, no create options)
+        mqtt_client_ = std::make_unique<mqtt::client>(
+            mqtt_config_.server_address,
+            mqtt_config_.client_id
+        );
+
+        RCLCPP_INFO(this->get_logger(), "MQTT client created successfully");
+
+        mqtt_connect();
+    } catch (const std::exception& e) {
+        RCLCPP_ERROR(this->get_logger(), "Exception in mqtt_configure: %s", e.what());
+        throw;
+    }
+}
+
+void HardwareInterface::mqtt_start_listen() {
+    RCLCPP_INFO(this->get_logger(), "MQTT listener started - consuming messages synchronously");
+
+    // Start a background thread to consume messages
+    if (!mqtt_reading_.load()) {
+        mqtt_reading_.store(true);
+        mqtt_read_thread_ = std::thread([this]() {
+            RCLCPP_INFO(this->get_logger(), "MQTT consumer thread started");
+
+            try {
+                while (mqtt_reading_.load() && mqtt_client_ && mqtt_client_->is_connected()) {
+                    mqtt::const_message_ptr msg;
+                    if (mqtt_client_->try_consume_message(&msg)) {
+                        mqtt_message_callback(msg->get_topic(), msg->get_payload_str(), this);
+                    } else {
+                        // No message available, sleep briefly to avoid busy-waiting
+                        std::this_thread::sleep_for(std::chrono::milliseconds(100));
+                    }
+                }
+            } catch (const mqtt::exception& exc) {
+                RCLCPP_ERROR(this->get_logger(), "MQTT consumer error: %s", exc.what());
+            }
+
+            RCLCPP_INFO(this->get_logger(), "MQTT consumer thread exiting");
+        });
+    }
+}
+
+void HardwareInterface::mqtt_connect() {
+    if (!mqtt_client_) {
+        RCLCPP_ERROR(this->get_logger(), "MQTT client is not initialized");
+        return;
+    }
+
+    try {
+        RCLCPP_INFO(this->get_logger(), "Connecting to MQTT broker...");
+
+        mqtt_client_->connect();
+        RCLCPP_INFO(this->get_logger(), "Connected to broker");
+
+        RCLCPP_INFO(this->get_logger(), "Subscribing to topic: %s", mqtt_config_.topic.c_str());
+        mqtt_client_->subscribe(mqtt_config_.topic, 1);
+        RCLCPP_INFO(this->get_logger(), "Subscribed to topic: %s", mqtt_config_.topic.c_str());
+    } catch (const mqtt::exception& exc) {
+        RCLCPP_ERROR(this->get_logger(), "MQTT Error: %s", exc.what());
+        throw;
+    }
+}
+
+void HardwareInterface::mqtt_stop_listen() {
+    if (mqtt_reading_.load()) {
+        mqtt_reading_.store(false);
+        if (mqtt_read_thread_.joinable()) {
+            mqtt_read_thread_.join();
+        }
+    }
+}
+
+void HardwareInterface::mqtt_close_connection() {
+    try {
+        mqtt_stop_listen();
+
+        if (mqtt_client_) {
+            if (mqtt_client_->is_connected()) {
+                mqtt_client_->disconnect();
+                RCLCPP_INFO(this->get_logger(), "Disconnected MQTT client");
+            }
+            mqtt_client_.reset();
+        }
+    } catch (const mqtt::exception& exc) {
+        RCLCPP_ERROR(this->get_logger(), "Error while disconnecting MQTT: %s", exc.what());
+    }
+}
+
+} // namespace assignments::two::g2_2025_lifecycle_node

src/g2_2025_imu_reader_pkg/src/g2_2025_lifecycle_node/nodes/HardwareInterface.hpp

@@ -0,0 +1,73 @@
+/* nodes/HardwareInterface.hpp
+ * Hardware interface implementation for the IMU reader system.
+ *
+ * Manages the serial communication with the IMU hardware, including initialization,
+ * data acquisition, and shutdown procedures.
+ *
+ * Changelog:
+ * [28-10-2025] M.khalaf: Implemented template.
+ * [28-10-2025] M.khalaf: Added serial communication support.
+ * [30-10-2025] M.khalaf: Added MQTT support.
+ * [20-10-2025] M.khalaf: Refactored code for readability.
+ * [30-10-2025] M.khalaf: Improved error handling.
+ * [31-10-2025] M.khalaf: Fixed serial read and mqtt configurations.
+ * [06-11-2025] Wessel T, Vincent W: Clean up code, remove uncessary imports
+ */
+#pragma once
+
+#include <memory>
+#include <thread>
+#include <atomic>
+#include <string>
+#include <nlohmann/json.hpp>
+#include <mqtt/client.h>
+
+#include "serialib.h"
+
+#include "rclcpp/rclcpp.hpp"
+#include "sensor_msgs/msg/imu.hpp"
+
+#include "MQTTParameters.hpp"
+
+namespace assignments::two::g2_2025_lifecycle_node {
+
+class HardwareInterface : public rclcpp::Node {
+
+public:
+    HardwareInterface(MQTTParameters mqtt_config);
+    ~HardwareInterface();
+
+    bool uart_open_device(const std::string& device_path, int baud_rate);
+    bool uart_device_is_open();
+    void uart_close_device();
+
+    void uart_start_read();
+    void uart_stop_read();
+
+    void mqtt_configure();
+    void mqtt_connect();
+
+    void mqtt_start_listen();
+    void mqtt_stop_listen();
+    void mqtt_close_connection();
+
+    void parse_and_publish_imu_data(const std::string& data);
+
+private:
+    rclcpp::Publisher<sensor_msgs::msg::Imu>::SharedPtr imu_publisher_;
+
+    serialib serial_;
+
+    MQTTParameters mqtt_config_;
+    std::unique_ptr<mqtt::client> mqtt_client_;
+
+    std::thread uart_read_thread_;
+    std::atomic_bool uart_reading_ {false};
+
+    std::thread mqtt_read_thread_;
+    std::atomic_bool mqtt_reading_ {false};
+
+    static void mqtt_message_callback(const std::string& topic, const std::string& payload, HardwareInterface* self);
+};
+
+}  // namespace assignments::two::g2_2025_lifecycle_node

src/g2_2025_imu_reader_pkg/src/g2_2025_lifecycle_node/nodes/LifecycleManager.cpp

@@ -0,0 +1,121 @@
+#include "LifecycleManager.hpp"
+#include "HardwareInterface.hpp"
+
+namespace assignments::two::g2_2025_lifecycle_node {
+
+LifecycleManager::LifecycleManager() : rclcpp_lifecycle::LifecycleNode("LifecycleManager") {
+    mqtt_config_.server_address =
+        this->declare_parameter<std::string>("mqtt_server_address", "tcp://localhost:1883");
+
+    mqtt_config_.client_id =
+        this->declare_parameter<std::string>("mqtt_client_id", "cpp_mqtt-client");
+
+    mqtt_config_.topic =
+        this->declare_parameter<std::string>("mqtt_subscribe_topic", "esp32/imu");
+
+    RCLCPP_INFO(this->get_logger(), "LifecycleManager node is ready");
+    device_path_ = this->declare_parameter<std::string>("device_path", "/dev/ttyUSB0");
+    baudrate_ = this->declare_parameter<int>("baudrate", 115200);
+    communication_type_ = this->declare_parameter<std::string>("comm_t", "serial");
+
+    hw_interface = std::make_shared<HardwareInterface>(mqtt_config_);
+}
+
+rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+LifecycleManager::on_error(const rclcpp_lifecycle::State&) {
+    RCLCPP_ERROR(this->get_logger(), "Error occurred in lifecycle...");
+    return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::FAILURE;
+}
+
+rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+LifecycleManager::on_configure(const rclcpp_lifecycle::State&) {
+    RCLCPP_INFO(this->get_logger(), "configuring lifecycle...");
+
+    if (communication_type_ == "mqtt") {
+        RCLCPP_INFO(this->get_logger(), "Setting up MQTT communication...");
+        hw_interface->mqtt_configure();
+    } else {
+        RCLCPP_INFO(this->get_logger(), "Using serial communication.");
+
+        if (!hw_interface->uart_open_device(device_path_, baudrate_)) {
+            RCLCPP_ERROR(this->get_logger(), "Failed to open hardware device during configuration.");
+            return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::FAILURE;
+        }
+    }
+
+    RCLCPP_INFO(this->get_logger(), "Lifecycle configured successfully.");
+    return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+}
+
+rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+LifecycleManager::on_cleanup(const rclcpp_lifecycle::State&) {
+    RCLCPP_INFO(this->get_logger(), "cleaning up lifecycle...");
+    if (communication_type_ == "mqtt") {
+        hw_interface->mqtt_close_connection();
+    } else {
+        if (hw_interface->uart_device_is_open()) {
+            hw_interface->uart_stop_read();
+            hw_interface->uart_close_device();
+        }
+    }
+
+    return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+}
+
+rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+LifecycleManager::on_activate(const rclcpp_lifecycle::State&) {
+    RCLCPP_INFO(this->get_logger(), "activating lifecycle...");
+
+    if (communication_type_ == "mqtt") {
+        RCLCPP_INFO(this->get_logger(), "Reading on MQTT...");
+        hw_interface->mqtt_start_listen();
+        return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+
+    } else {
+        RCLCPP_INFO(this->get_logger(), "Reading on Serial...");
+        hw_interface->uart_start_read();
+    }
+
+    return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+}
+
+rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+LifecycleManager::on_deactivate(const rclcpp_lifecycle::State&) {
+    RCLCPP_INFO(this->get_logger(), "deactivating lifecycle...");
+
+    if (communication_type_ == "mqtt")
+    {
+        hw_interface->mqtt_stop_listen();
+        return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+
+    } else
+    {
+        if (!hw_interface->uart_device_is_open()) {
+            RCLCPP_ERROR(this->get_logger(), "Hardware device is not open during activation.");
+            hw_interface->uart_close_device();
+        }
+        RCLCPP_INFO(this->get_logger(), "Hardware device is open,closing device...");
+        hw_interface->uart_stop_read();
+
+        RCLCPP_INFO(this->get_logger(), "Lifecycle deactivated successfully.");
+        return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+    }
+}
+
+rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+LifecycleManager::on_shutdown(const rclcpp_lifecycle::State&) {
+    if (communication_type_ == "mqtt") {
+        hw_interface->mqtt_close_connection();
+        return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+    } else {
+        if (hw_interface->uart_device_is_open()) {
+            hw_interface->uart_stop_read();
+            hw_interface->uart_close_device();
+        }
+    }
+
+    RCLCPP_INFO(this->get_logger(), "shutting down lifecycle...");
+    return rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::SUCCESS;
+}
+
+}  // namespace assignments::two::g2_2025_lifecycle_node

src/g2_2025_imu_reader_pkg/src/g2_2025_lifecycle_node/nodes/LifecycleManager.hpp

@@ -0,0 +1,51 @@
+/* nodes/LifecycleManager.hpp
+ * Lifecycle node implementation for managing the lifecycle of the IMU reader system.
+ *
+ * Manages the different states of the lifecycle node, including configuration,
+ * and hardware interface management.
+ *
+ * Changelog:
+ * [28-10-2025] M.khalaf: Implemented template.
+ */
+#pragma once
+
+#include "rclcpp/rclcpp.hpp"
+#include "rclcpp_lifecycle/lifecycle_node.hpp"
+#include "std_msgs/msg/string.hpp"
+#include "HardwareInterface.hpp"
+
+#include "MQTTParameters.hpp"
+
+namespace assignments::two::g2_2025_lifecycle_node {
+
+class LifecycleManager : public rclcpp_lifecycle::LifecycleNode {
+public:
+    LifecycleManager();
+
+    // Hardware interface to interact with the IMU device. Made public for testing purposes
+    std::shared_ptr<HardwareInterface> hw_interface;
+
+private:
+    std::string device_path_;
+    int baudrate_;
+    std::string communication_type_;
+
+    MQTTParameters mqtt_config_ {};
+
+    rclcpp::Publisher<sensor_msgs::msg::Imu>::SharedPtr imu_publisher_;
+
+    rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+        on_error(const rclcpp_lifecycle::State&);
+    rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+        on_cleanup(const rclcpp_lifecycle::State&);
+    rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+        on_configure(const rclcpp_lifecycle::State&);
+    rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+        on_activate(const rclcpp_lifecycle::State&);
+    rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+        on_deactivate(const rclcpp_lifecycle::State&);
+    rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn
+        on_shutdown(const rclcpp_lifecycle::State&);
+};
+
+}  // namespace assignments::two::g2_2025_lifecycle_node

src/g2_2025_imu_reader_pkg/src/g2_2025_lifecycle_node/nodes/MQTTParameters.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <string>
+
+namespace assignments::two {
+
+struct MQTTParameters {
+  std::string server_address;
+  std::string client_id;
+  std::string topic;
+};
+
+} // namespace assignments::two

src/g2_2025_imu_reader_pkg/test/LifecycleManager.test.cpp

@@ -0,0 +1,235 @@
+#include <gtest/gtest.h>
+#include <rclcpp/rclcpp.hpp>
+#include <rclcpp_lifecycle/lifecycle_node.hpp>
+#include <lifecycle_msgs/msg/state.hpp>
+
+#include "g2_2025_lifecycle_node/nodes/LifecycleManager.hpp"
+
+using namespace assignments::two::g2_2025_lifecycle_node;
+
+class LifecycleManagerTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        // Initialize ROS2
+        rclcpp::init(0, nullptr);
+    }
+
+    void TearDown() override {
+        // Shutdown ROS2
+        rclcpp::shutdown();
+    }
+};
+
+TEST_F(LifecycleManagerTest, ConstructorTest) {
+    // Test 1: Verifies that LifecycleManager can be instantiated without crashing
+    ASSERT_NO_THROW({
+        auto node = std::make_shared<LifecycleManager>();
+        EXPECT_NE(node, nullptr);
+    });
+}
+
+TEST_F(LifecycleManagerTest, ParameterDeclarationTest) {
+    // Test 2: Verify all required parameters are declared with correct defaults
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Check that parameters exist
+    auto device_path = node->get_parameter("device_path").as_string();
+    auto baudrate = node->get_parameter("baudrate").as_int();
+    auto comm_t = node->get_parameter("comm_t").as_string();
+
+    EXPECT_EQ(device_path, "/dev/ttyUSB0");
+    EXPECT_EQ(baudrate, 115200);
+    EXPECT_EQ(comm_t, "serial");
+}
+
+TEST_F(LifecycleManagerTest, ParameterRuntimeReadTest) {
+    // Test 3: Verify parameters can be read at runtime
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Set new parameter values
+    node->set_parameter(rclcpp::Parameter("device_path", "/dev/ttyACM0"));
+    node->set_parameter(rclcpp::Parameter("comm_t", "mqtt"));
+
+    // Verify new values are read
+    auto device_path = node->get_parameter("device_path").as_string();
+    auto comm_t = node->get_parameter("comm_t").as_string();
+
+    EXPECT_EQ(device_path, "/dev/ttyACM0");
+    EXPECT_EQ(comm_t, "mqtt");
+}
+
+
+TEST_F(LifecycleManagerTest, InitialStateTest) {
+    // Test 4: Verify node starts in UNCONFIGURED state
+    auto node = std::make_shared<LifecycleManager>();
+
+    EXPECT_EQ(node->get_current_state().id(), lifecycle_msgs::msg::State::PRIMARY_STATE_UNCONFIGURED);
+}
+
+TEST_F(LifecycleManagerTest, ConfigureSerialModeTest) {
+    // Test 5: Test on_configure in serial communication mode
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Use /dev/null as a safe test device
+    node->set_parameter(rclcpp::Parameter("device_path", "/dev/null"));
+    node->set_parameter(rclcpp::Parameter("comm_t", "serial"));
+
+    // Attempt to configure
+    node->configure();
+
+    // Check state after configure
+    auto state_id = node->get_current_state().id();
+    // Should be INACTIVE (2) if successful or UNCONFIGURED (0) if failed
+    EXPECT_TRUE(state_id == lifecycle_msgs::msg::State::PRIMARY_STATE_INACTIVE ||
+                state_id == lifecycle_msgs::msg::State::PRIMARY_STATE_UNCONFIGURED);
+}
+
+TEST_F(LifecycleManagerTest, ConfigureMQTTModeTest) {
+    // Test 6: Test on_configure in MQTT communication mode
+    auto node = std::make_shared<LifecycleManager>();
+
+    node->set_parameter(rclcpp::Parameter("comm_t", "mqtt"));
+
+    // Attempt to configure (MQTT setup doesn't require actual broker)
+    node->configure();
+
+    //should be INACTIVE or UNCONFIGURED
+    auto state_id = node->get_current_state().id();
+    EXPECT_TRUE(state_id == lifecycle_msgs::msg::State::PRIMARY_STATE_INACTIVE ||
+                state_id == lifecycle_msgs::msg::State::PRIMARY_STATE_UNCONFIGURED);
+}
+
+TEST_F(LifecycleManagerTest, ConfigureSerialFailureTest) {
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Use /dev/null which should open successfully for this test
+    node->set_parameter(rclcpp::Parameter("device_path", "/dev/null"));
+    node->set_parameter(rclcpp::Parameter("comm_t", "serial"));
+
+    // Attempt to configure
+    node->configure();
+
+    SUCCEED();
+}
+
+TEST_F(LifecycleManagerTest, DeactivateSerialModeTest) {
+    // Test 8: Test on_deactivate in serial communication mode
+    auto node = std::make_shared<LifecycleManager>();
+
+    node->set_parameter(rclcpp::Parameter("device_path", "/dev/null"));
+    node->set_parameter(rclcpp::Parameter("comm_t", "serial"));
+
+    // Configure to INACTIVE state
+    node->configure();
+    auto config_state = node->get_current_state().id();
+
+    if (config_state == lifecycle_msgs::msg::State::PRIMARY_STATE_INACTIVE) {
+        // Deactivate from INACTIVE
+        node->deactivate();
+        auto final_state = node->get_current_state().id();
+        // Should still be in INACTIVE or return to UNCONFIGURED
+        EXPECT_TRUE(final_state == lifecycle_msgs::msg::State::PRIMARY_STATE_INACTIVE ||
+                    final_state == lifecycle_msgs::msg::State::PRIMARY_STATE_UNCONFIGURED);
+    }
+}
+
+
+TEST_F(LifecycleManagerTest, DevicePathParameterTest) {
+    // Test 24: Verify device_path parameter is correctly used
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Test multiple device paths
+    std::vector<std::string> device_paths = {"/dev/ttyUSB0", "/dev/ttyACM0", "/dev/null"};
+
+    for (const auto& path : device_paths) {
+        node->set_parameter(rclcpp::Parameter("device_path", path));
+        auto retrieved_path = node->get_parameter("device_path").as_string();
+        EXPECT_EQ(retrieved_path, path);
+    }
+}
+
+TEST_F(LifecycleManagerTest, BaudRateParameterTest) {
+    // Test 25: Verify baudrate parameter is correctly used
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Test multiple baud rates
+    std::vector<int> baud_rates = {9600, 115200, 230400};
+
+    for (int baud : baud_rates) {
+        node->set_parameter(rclcpp::Parameter("baudrate", baud));
+        auto retrieved_baud = node->get_parameter("baudrate").as_int();
+        EXPECT_EQ(retrieved_baud, baud);
+    }
+}
+
+TEST_F(LifecycleManagerTest, ParameterUpdateBehaviorTest) {
+    // Test 19: Test that parameter changes are respected across transitions
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Start with serial
+    node->set_parameter(rclcpp::Parameter("comm_t", "serial"));
+    node->set_parameter(rclcpp::Parameter("device_path", "/dev/null"));
+
+    auto comm_type = node->get_parameter("comm_t").as_string();
+    EXPECT_EQ(comm_type, "serial");
+
+    // Switch to MQTT
+    node->set_parameter(rclcpp::Parameter("comm_t", "mqtt"));
+    comm_type = node->get_parameter("comm_t").as_string();
+    EXPECT_EQ(comm_type, "mqtt");
+
+    // Switch back to serial
+    node->set_parameter(rclcpp::Parameter("comm_t", "serial"));
+    comm_type = node->get_parameter("comm_t").as_string();
+    EXPECT_EQ(comm_type, "serial");
+}
+
+TEST_F(LifecycleManagerTest, ResourceCleanupTest) {
+    // Test 9: Verify resources are properly cleaned up
+    {
+        auto node = std::make_shared<LifecycleManager>();
+
+        node->set_parameter(rclcpp::Parameter("device_path", "/dev/null"));
+        node->set_parameter(rclcpp::Parameter("comm_t", "serial"));
+
+        // Just configure, don't activate (avoid thread spawning)
+        node->configure();
+
+        // Node goes out of scope; verify no crashes
+    }
+
+    // If we reach here without crashes, cleanup was successful
+    SUCCEED();
+}
+
+TEST_F(LifecycleManagerTest, ErrorLoggingTest) {
+    // Test 10: Verify error messages are logged during failures
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Set invalid device path to trigger error
+    node->set_parameter(rclcpp::Parameter("device_path", "/dev/nonexistent_device_xyz"));
+    node->set_parameter(rclcpp::Parameter("comm_t", "serial"));
+
+    // This should attempt to configure
+    node->configure();
+
+    // The node may still transition state, but we verify it handles errors gracefully
+    // by not crashing
+    SUCCEED();
+}
+
+TEST_F(LifecycleManagerTest, HardwareInterfaceIntegrationTest) {
+    // Test 11: Verify complete integration with HardwareInterface
+    auto node = std::make_shared<LifecycleManager>();
+
+    // Verify HardwareInterface instance is created
+    EXPECT_NE(node->hw_interface, nullptr);
+
+    // Verify we can make method calls on the hardware interface
+    EXPECT_FALSE(node->hw_interface->uart_device_is_open());
+}
+
+int main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}