# Software Feature Specification

## SF-DAQ: Sensor Data Acquisition

**Software Feature ID:** SF-DAQ  
**Mapped System Feature:** F-DAQ (Sensor Data Acquisition Features)  
**Version:** 1.0  
**Date:** 2025-02-01  

## 1. Feature Overview

The Sensor Data Acquisition software feature implements the capability to acquire, process, and prepare environmental sensor data for persistence and communication. This feature provides the software implementation of multi-sensor data acquisition, high-frequency sampling with local filtering, and timestamped data generation.

### 1.1 Mapped System Features

- **F-DAQ-01**: Multi-Sensor Data Acquisition
- **F-DAQ-02**: High-Frequency Sampling and Local Filtering  
- **F-DAQ-03**: Timestamped Sensor Data Generation

## 2. Static View - Component Architecture

```mermaid
graph TB
    subgraph "Application Layer"
        SM[Sensor Manager]
        DP[Data Pool]
    end
    
    subgraph "Driver Layer"
        SD_TEMP[Temperature Driver]
        SD_HUM[Humidity Driver]
        SD_CO2[CO2 Driver]
        SD_NH3[Ammonia Driver]
        SD_VOC[VOC Driver]
        SD_LIGHT[Light Driver]
    end
    
    subgraph "Hardware Abstraction"
        I2C[I2C Wrapper]
        ADC[ADC Wrapper]
        GPIO[GPIO Wrapper]
    end
    
    SM --> SD_TEMP
    SM --> SD_HUM
    SM --> SD_CO2
    SM --> SD_NH3
    SM --> SD_VOC
    SM --> SD_LIGHT
    
    SD_TEMP --> I2C
    SD_HUM --> I2C
    SD_CO2 --> I2C
    SD_NH3 --> ADC
    SD_VOC --> ADC
    SD_LIGHT --> ADC
    
    I2C --> GPIO
    ADC --> GPIO
    
    SM --> DP
```

### 2.1 Component Interfaces

#### 2.1.1 Sensor Manager Interfaces

**Provided Interfaces:**
- `ISensorManager`: Main sensor management interface
- `ISensorCallback`: Sensor data callback interface

**Required Interfaces:**
- `ISensorDriver`: Generic sensor driver interface
- `IDataPool`: Data storage interface
- `IEventSystem`: Event notification interface

#### 2.1.2 Sensor Driver Interfaces

**Provided Interfaces:**
- `ISensorDriver`: Generic sensor driver interface
- `ITemperatureSensor`: Temperature-specific interface
- `IHumiditySensor`: Humidity-specific interface
- `ICO2Sensor`: CO2-specific interface

**Required Interfaces:**
- `II2C`: I2C communication interface
- `IADC`: ADC interface
- `IGPIO`: GPIO interface

## 3. Dynamic View - Sensor Acquisition Sequence

```mermaid
sequenceDiagram
    participant SM as Sensor Manager
    participant SD as Sensor Driver
    participant HW as Hardware Layer
    participant DP as Data Pool
    participant ES as Event System
    
    SM->>SM: Start Acquisition Cycle
    loop For each enabled sensor
        SM->>SD: initiateSampling()
        loop N samples (configurable)
            SD->>HW: readRawValue()
            HW-->>SD: raw_value
        end
        SD->>SD: applyFilter(samples[])
        SD-->>SM: filtered_value
        SM->>SM: generateTimestamp()
        SM->>DP: storeSensorData(sensor_id, value, timestamp, validity)
        SM->>ES: publishSensorEvent(sensor_data)
    end
    SM->>SM: Schedule Next Cycle
```

## 4. Software Constraints

### 4.1 Performance Constraints
- **SWC-DAQ-001**: Sensor acquisition cycle must complete within 100ms per sensor
- **SWC-DAQ-002**: Memory allocation for sensor data must be deterministic and bounded
- **SWC-DAQ-003**: Sensor sampling must not block system-critical tasks

### 4.2 Resource Constraints
- **SWC-DAQ-004**: Maximum 10 concurrent sensor instances supported
- **SWC-DAQ-005**: Sensor data buffer size limited to 1KB per sensor
- **SWC-DAQ-006**: Filter algorithms must execute in O(n) time complexity

### 4.3 Reliability Constraints
- **SWC-DAQ-007**: Sensor failure must not affect other sensor operations
- **SWC-DAQ-008**: Invalid sensor data must be marked with appropriate validity flags
- **SWC-DAQ-009**: Sensor warmup periods must be enforced before data publication

## 5. Traceability Matrix - Software Requirements

| Software Requirement ID | Feature Mapping | Component | Verification Method |
|-------------------------|-----------------|-----------|-------------------|
| SWR-DAQ-001 | F-DAQ-01 | Sensor Manager | Unit Test |
| SWR-DAQ-002 | F-DAQ-01 | Sensor Drivers | Integration Test |
| SWR-DAQ-003 | F-DAQ-01 | Sensor Manager | Unit Test |
| SWR-DAQ-004 | F-DAQ-02 | Sensor Manager | Unit Test |
| SWR-DAQ-005 | F-DAQ-02 | Sensor Drivers | Unit Test |
| SWR-DAQ-006 | F-DAQ-02 | Sensor Manager | Integration Test |
| SWR-DAQ-007 | F-DAQ-03 | Sensor Manager | Unit Test |
| SWR-DAQ-008 | F-DAQ-03 | Sensor Manager | Unit Test |
| SWR-DAQ-009 | F-DAQ-03 | Data Pool | Integration Test |
| SWR-DAQ-010 | F-DAQ-02 | Sensor Manager | Performance Test |
| SWR-DAQ-011 | F-DAQ-04 | Sensor Manager | State Machine Test |
| SWR-DAQ-012 | F-DAQ-04 | Sensor Manager | Unit Test |
| SWR-DAQ-013 | F-DAQ-04 | Sensor Drivers | Integration Test |

## 6. Implementation Notes

### 6.1 Sensor Driver Architecture
- Each sensor type implements the `ISensorDriver` interface
- Drivers are responsible for hardware-specific communication protocols
- Filter algorithms are pluggable and configurable via Machine Constants

### 6.2 Data Flow
- Raw sensor data flows from drivers to Sensor Manager
- Filtered data is stored in Data Pool for persistence
- Sensor events are published via Event System for communication

### 6.3 Error Handling
- Sensor communication errors are logged and reported via diagnostics
- Failed sensors are marked as invalid but do not stop other sensor operations
- Sensor state machine tracks initialization, warmup, stable, and failed states