# Feature Specification: Data Quality & Calibration
# Feature ID: F-DQC (F-DQC-001 to F-DQC-005)

**Document Type:** Feature Specification  
**Version:** 1.0  
**Date:** 2025-01-19  
**Feature Category:** Data Quality & Calibration  

## 1. Feature Overview

### 1.1 Feature Purpose

The Data Quality & Calibration feature ensures that all sensor data generated by the ASF Sensor Hub is valid, trustworthy, correctly classified, and calibrated throughout the system lifecycle. This feature provides mechanisms for automatic sensor identification, compatibility enforcement, failure detection, and centralized calibration management.

### 1.2 Feature Scope

**In Scope:**
- Automatic sensor detection and identification
- Sensor-slot compatibility enforcement
- Real-time sensor failure detection and isolation
- Machine constants and calibration parameter management
- Redundant sensor support and sensor fusion

**Out of Scope:**
- Sensor hardware manufacturing and design
- External calibration equipment and procedures
- Main Hub calibration algorithms
- Sensor replacement and maintenance procedures

## 2. Sub-Features

### 2.1 F-DQC-001: Automatic Sensor Detection

**Description:** Dynamic detection and identification of connected sensors using hardware-based presence detection mechanisms.

**Detection Methods:**
- **GPIO Presence Pins:** Dedicated detection signals per sensor slot
- **I2C Device Scanning:** Automatic I2C address enumeration
- **Device ID Reading:** Sensor-specific identification protocols
- **Electrical Signature:** Voltage/resistance-based detection

**Detection Process:**
```mermaid
sequenceDiagram
    participant SM as Sensor Manager
    participant DD as Device Detector
    participant SD as Sensor Driver
    participant MC as Machine Constants
    
    Note over SM,MC: Sensor Detection Cycle
    
    SM->>DD: scanForSensors()
    
    loop For each sensor slot
        DD->>DD: checkPresencePin(slot_id)
        alt Presence detected
            DD->>SD: probeSensorType(slot_id)
            SD->>SD: readDeviceID()
            SD-->>DD: sensor_type_info
            DD->>MC: validateSensorSlot(slot_id, sensor_type)
            MC-->>DD: validation_result
        end
    end
    
    DD-->>SM: detected_sensors_list
    SM->>SM: updateSensorRegistry()
```

### 2.2 F-DQC-002: Sensor Type Enforcement

**Description:** Enforcement of sensor-slot compatibility to prevent incorrect sensor installation and configuration errors.

**Enforcement Mechanisms:**
- **Physical Slot Design:** Mechanical keying for sensor types
- **Electrical Validation:** Pin configuration verification
- **Software Validation:** Machine constants cross-reference
- **Protocol Validation:** Communication interface verification

**Slot Mapping Table:**
| Slot ID | Sensor Type | Interface | Detection Pin | Validation Method |
|---------|-------------|-----------|---------------|-------------------|
| SLOT_01 | Temperature | I2C/Analog | GPIO_12 | Device ID + Range |
| SLOT_02 | Humidity | I2C | GPIO_13 | Device ID + Protocol |
| SLOT_03 | CO2 | UART/I2C | GPIO_14 | Device ID + Calibration |
| SLOT_04 | NH3 | Analog/I2C | GPIO_15 | Range + Sensitivity |
| SLOT_05 | VOC | I2C | GPIO_16 | Device ID + Algorithm |
| SLOT_06 | PM | UART/I2C | GPIO_17 | Protocol + Range |
| SLOT_07 | Light | Analog/I2C | GPIO_18 | Range + Spectral |

### 2.3 F-DQC-003: Sensor Failure Detection

**Description:** Continuous monitoring of sensor behavior to detect and isolate failures in real-time.

**Failure Detection Methods:**
- **Communication Timeouts:** I2C/UART/SPI response monitoring
- **Range Validation:** Out-of-specification value detection
- **Trend Analysis:** Abnormal rate-of-change detection
- **Cross-Validation:** Multi-sensor consistency checking
- **Health Monitoring:** Sensor self-diagnostic features

**Failure Classification:**
```c
typedef enum {
    SENSOR_FAILURE_NONE = 0,
    SENSOR_FAILURE_COMMUNICATION,    // Timeout, NACK, protocol error
    SENSOR_FAILURE_OUT_OF_RANGE,     // Values outside physical limits
    SENSOR_FAILURE_STUCK_VALUE,      // No change over time
    SENSOR_FAILURE_ERRATIC,          // Excessive noise or variation
    SENSOR_FAILURE_CALIBRATION,      // Drift beyond acceptable limits
    SENSOR_FAILURE_HARDWARE,         // Self-diagnostic failure
    SENSOR_FAILURE_UNKNOWN           // Unclassified failure
} sensor_failure_type_t;
```

### 2.4 F-DQC-004: Machine Constants & Calibration Management

**Description:** Centralized management of sensor configuration, calibration parameters, and system identity information.

**Machine Constants Structure:**
```c
typedef struct {
    // System Identity
    char device_id[32];
    char site_id[16];
    char house_id[16];
    uint32_t firmware_version;
    
    // Sensor Configuration
    sensor_config_t sensors[MAX_SENSORS];
    
    // Calibration Parameters
    calibration_params_t calibration[MAX_SENSORS];
    
    // Communication Settings
    comm_config_t communication;
    
    // System Limits
    system_limits_t limits;
    
    // Validation
    uint32_t checksum;
    uint64_t timestamp;
} machine_constants_t;

typedef struct {
    uint8_t sensor_id;
    sensor_type_t type;
    bool enabled;
    uint32_t sampling_rate;
    filter_config_t filter;
    float min_value, max_value;
    char unit[8];
} sensor_config_t;

typedef struct {
    float offset;
    float scale;
    float[] polynomial_coeffs;
    uint8_t coeff_count;
    uint64_t calibration_date;
    uint32_t calibration_interval;
} calibration_params_t;
```

### 2.5 F-DQC-005: Redundant Sensor Support

**Description:** Support for redundant sensors and sensor fusion for critical measurements.

**Redundancy Strategies:**
- **Dual Sensors:** Two sensors of same type for critical parameters
- **Cross-Validation:** Different sensor types measuring related parameters
- **Voting Logic:** Majority voting for multiple sensors
- **Graceful Degradation:** Fallback to single sensor operation

**Sensor Fusion Algorithm:**
```mermaid
graph TB
    subgraph "Sensor Fusion Process"
        S1[Sensor 1] --> V[Validator]
        S2[Sensor 2] --> V
        S3[Sensor 3] --> V
        V --> F[Fusion Algorithm]
        F --> O[Output Value]
        F --> C[Confidence Level]
    end
    
    subgraph "Fusion Methods"
        AVG[Weighted Average]
        MED[Median Filter]
        KAL[Kalman Filter]
        VOT[Voting Logic]
    end
    
    F --> AVG
    F --> MED
    F --> KAL
    F --> VOT
```

## 3. Requirements Coverage

### 3.1 System Requirements (SR-XXX)

| Feature | System Requirements | Description |
|---------|-------------------|-------------|
| **F-DQC-001** | SR-DQC-001, SR-DQC-002 | Automatic sensor detection and enumeration |
| **F-DQC-002** | SR-DQC-003, SR-DQC-004 | Sensor type enforcement and slot validation |
| **F-DQC-003** | SR-DQC-005, SR-DQC-006 | Failure detection and isolation |
| **F-DQC-004** | SR-DQC-007, SR-DQC-008 | Machine constants management and persistence |
| **F-DQC-005** | SR-DQC-009, SR-DQC-010 | Redundant sensor support and fusion |

### 3.2 Software Requirements (SWR-XXX)

| Feature | Software Requirements | Implementation Details |
|---------|---------------------|----------------------|
| **F-DQC-001** | SWR-DQC-001, SWR-DQC-002, SWR-DQC-003 | Detection algorithms, device probing, registry management |
| **F-DQC-002** | SWR-DQC-004, SWR-DQC-005, SWR-DQC-006 | Slot mapping, validation logic, error reporting |
| **F-DQC-003** | SWR-DQC-007, SWR-DQC-008, SWR-DQC-009 | Health monitoring, failure classification, isolation |
| **F-DQC-004** | SWR-DQC-010, SWR-DQC-011, SWR-DQC-012 | MC structure, persistence, update mechanisms |
| **F-DQC-005** | SWR-DQC-013, SWR-DQC-014, SWR-DQC-015 | Fusion algorithms, redundancy management, voting logic |

## 4. Component Implementation Mapping

### 4.1 Primary Components

| Component | Responsibility | Location |
|-----------|---------------|----------|
| **Machine Constant Manager** | MC loading, validation, update coordination | `application_layer/business_stack/machine_constant_manager/` |
| **Sensor Manager** | Detection coordination, failure monitoring | `application_layer/business_stack/sensor_manager/` |
| **Device Detector** | Hardware detection, sensor probing | `drivers/device_detector/` |
| **Calibration Manager** | Calibration algorithms, parameter management | `application_layer/calibration/` |

### 4.2 Supporting Components

| Component | Support Role | Interface |
|-----------|-------------|-----------|
| **Sensor Drivers** | Hardware interface, device identification | `drivers/sensors/` |
| **Event System** | Detection events, failure notifications | `application_layer/business_stack/event_system/` |
| **Data Persistence** | MC storage, calibration data persistence | `application_layer/DP_stack/persistence/` |
| **Diagnostics Task** | Failure logging, health reporting | `application_layer/diag_task/` |

### 4.3 Component Interaction Diagram

```mermaid
graph TB
    subgraph "Data Quality & Calibration Feature"
        MCM[Machine Constant Manager]
        SM[Sensor Manager]
        DD[Device Detector]
        CAL[Calibration Manager]
    end
    
    subgraph "Supporting Components"
        SD[Sensor Drivers]
        ES[Event System]
        DP[Data Persistence]
        DIAG[Diagnostics Task]
    end
    
    subgraph "Hardware"
        SENSORS[Physical Sensors]
        GPIO[Detection Pins]
        I2C[I2C Bus]
        UART[UART Interface]
    end
    
    MCM <--> DP
    MCM --> SM
    MCM --> CAL
    
    SM <--> ES
    SM --> DD
    SM --> DIAG
    
    DD --> SD
    DD --> GPIO
    
    CAL --> MCM
    CAL <--> DP
    
    SD --> I2C
    SD --> UART
    SD --> SENSORS
    
    ES -.->|Detection Events| SM
    ES -.->|Failure Events| DIAG
    DIAG -.->|Health Data| SM
```

### 4.4 Detection and Validation Flow

```mermaid
sequenceDiagram
    participant HW as Hardware
    participant DD as Device Detector
    participant SD as Sensor Driver
    participant SM as Sensor Manager
    participant MCM as MC Manager
    participant ES as Event System
    participant DIAG as Diagnostics
    
    Note over HW,DIAG: Sensor Detection and Validation
    
    SM->>DD: initiateSensorScan()
    
    loop For each sensor slot
        DD->>HW: checkPresencePin(slot_id)
        HW-->>DD: presence_status
        
        alt Sensor present
            DD->>SD: probeSensorType(slot_id)
            SD->>HW: readDeviceID()
            HW-->>SD: device_info
            SD-->>DD: sensor_type_info
            
            DD->>MCM: validateSensorSlot(slot_id, sensor_type)
            MCM-->>DD: validation_result
            
            alt Validation successful
                DD->>SM: registerSensor(slot_id, sensor_info)
                SM->>ES: publish(SENSOR_DETECTED, sensor_info)
            else Validation failed
                DD->>DIAG: reportValidationError(slot_id, error)
                DIAG->>ES: publish(SENSOR_VALIDATION_FAILED, error)
            end
        end
    end
    
    DD-->>SM: scanComplete(detected_sensors)
    SM->>ES: publish(SENSOR_SCAN_COMPLETE, summary)
```

## 5. Feature Behavior

### 5.1 Normal Operation Flow

1. **System Initialization:**
   - Load machine constants from persistent storage
   - Validate MC integrity and version compatibility
   - Initialize sensor detection and calibration systems
   - Perform initial sensor scan and validation

2. **Sensor Detection Cycle:**
   - Scan all sensor slots for presence
   - Identify sensor types and validate compatibility
   - Register detected sensors in system registry
   - Configure sensors according to machine constants

3. **Continuous Monitoring:**
   - Monitor sensor health and communication status
   - Detect failures and classify failure types
   - Apply calibration corrections to sensor data
   - Manage redundant sensors and sensor fusion

4. **Configuration Management:**
   - Handle machine constants updates from Main Hub
   - Validate new configurations before application
   - Coordinate system teardown for MC updates
   - Persist updated configurations to storage

### 5.2 Error Handling

| Error Condition | Detection Method | Response Action |
|----------------|------------------|-----------------|
| **Sensor Mismatch** | Type validation against MC | Reject sensor, log diagnostic event |
| **Communication Failure** | Timeout or protocol error | Mark sensor as faulty, continue with others |
| **Calibration Drift** | Value trend analysis | Flag for recalibration, continue operation |
| **MC Corruption** | Checksum validation | Use backup MC, request update from Main Hub |
| **Detection Hardware Failure** | GPIO or I2C failure | Disable detection, use last known configuration |

### 5.3 State-Dependent Behavior

| System State | Feature Behavior |
|-------------|------------------|
| **INIT** | Load MC, detect sensors, validate configuration |
| **RUNNING** | Continuous monitoring, failure detection, calibration |
| **WARNING** | Enhanced monitoring, diagnostic reporting |
| **FAULT** | Minimal operation, preserve sensor states |
| **MC_UPDATE** | Stop monitoring, update MC, re-detect sensors |
| **SERVICE** | Full diagnostic access, manual sensor control |
| **SD_DEGRADED** | Continue operation, no MC persistence |

## 6. Feature Constraints

### 6.1 Timing Constraints

- **Detection Cycle:** Maximum 5 seconds for complete sensor scan
- **Failure Detection:** Maximum 3 seconds to detect communication failure
- **MC Update:** Maximum 30 seconds for complete MC reload
- **Calibration Application:** Maximum 100ms per sensor

### 6.2 Resource Constraints

- **Memory Usage:** Maximum 8KB for MC data and sensor registry
- **Detection Frequency:** Maximum once per minute for presence scan
- **Calibration Storage:** Maximum 1KB per sensor for calibration data
- **Failure History:** Maximum 100 failure events in memory

### 6.3 Quality Constraints

- **Detection Accuracy:** 99.9% accurate sensor presence detection
- **Type Validation:** 100% prevention of incorrect sensor installation
- **Failure Detection:** 95% of failures detected within 10 seconds
- **Calibration Accuracy:** Within ±2% of reference standards

## 7. Interface Specifications

### 7.1 Machine Constant Manager API

```c
// Machine constants management
bool mcMgr_initialize(void);
bool mcMgr_loadMachineConstants(machine_constants_t* mc);
bool mcMgr_validateMachineConstants(const machine_constants_t* mc);
bool mcMgr_updateMachineConstants(const machine_constants_t* new_mc);
bool mcMgr_backupMachineConstants(void);

// Sensor configuration access
bool mcMgr_getSensorConfig(uint8_t sensor_id, sensor_config_t* config);
bool mcMgr_getCalibrationParams(uint8_t sensor_id, calibration_params_t* params);
bool mcMgr_validateSensorSlot(uint8_t slot_id, sensor_type_t sensor_type);

// System configuration
bool mcMgr_getSystemIdentity(system_identity_t* identity);
bool mcMgr_getCommunicationConfig(comm_config_t* config);
bool mcMgr_getSystemLimits(system_limits_t* limits);
```

### 7.2 Device Detector API

```c
// Detection operations
bool detector_initialize(void);
bool detector_scanSensors(detected_sensor_t* sensors, size_t* count);
bool detector_probeSensorType(uint8_t slot_id, sensor_type_info_t* info);
bool detector_validateSensorPresence(uint8_t slot_id);

// Hardware interface
bool detector_checkPresencePin(uint8_t slot_id);
bool detector_readDeviceID(uint8_t slot_id, device_id_t* id);
bool detector_testCommunication(uint8_t slot_id, comm_interface_t interface);
```

### 7.3 Calibration Manager API

```c
// Calibration operations
bool cal_initialize(void);
bool cal_applyCalibratio(uint8_t sensor_id, float raw_value, float* calibrated_value);
bool cal_updateCalibrationParams(uint8_t sensor_id, const calibration_params_t* params);
bool cal_validateCalibration(uint8_t sensor_id, validation_result_t* result);

// Calibration management
bool cal_scheduleRecalibration(uint8_t sensor_id, uint32_t interval_days);
bool cal_isCalibrationExpired(uint8_t sensor_id);
bool cal_getCalibrationStatus(uint8_t sensor_id, calibration_status_t* status);
```

## 8. Testing and Validation

### 8.1 Unit Testing

- **Detection Logic:** Mock hardware for detection algorithm testing
- **Validation Rules:** Sensor-slot compatibility matrix testing
- **Calibration Math:** Known input/output calibration validation
- **MC Management:** Configuration loading and validation testing

### 8.2 Integration Testing

- **Hardware Detection:** Real sensor hardware detection testing
- **Communication Interfaces:** I2C, UART, SPI sensor communication
- **Event Integration:** Detection and failure event publication
- **Persistence Integration:** MC storage and retrieval testing

### 8.3 System Testing

- **Multi-Sensor Detection:** All 7 sensor types simultaneously
- **Failure Scenarios:** Sensor disconnection and failure injection
- **MC Update Testing:** Complete configuration update scenarios
- **Long-Duration Testing:** 48-hour continuous monitoring

### 8.4 Acceptance Criteria

- All supported sensor types correctly detected and identified
- 100% prevention of incorrect sensor-slot configurations
- Failure detection within specified timing constraints
- Machine constants updates complete without data loss
- Calibration accuracy within specified tolerances
- No false positive or negative detection events

## 9. Dependencies

### 9.1 Internal Dependencies

- **Sensor Manager:** Sensor lifecycle and state management
- **Event System:** Detection and failure event communication
- **Data Persistence:** Machine constants and calibration storage
- **Diagnostics Task:** Failure logging and health reporting

### 9.2 External Dependencies

- **ESP-IDF Framework:** GPIO, I2C, UART, SPI drivers
- **Hardware Sensors:** Physical sensor devices and interfaces
- **Detection Hardware:** Presence pins and identification circuits
- **Main Hub:** Machine constants updates and calibration data

## 10. Future Enhancements

### 10.1 Planned Improvements

- **AI-Based Detection:** Machine learning for sensor identification
- **Predictive Calibration:** Drift prediction and automatic correction
- **Advanced Fusion:** Multi-sensor data fusion algorithms
- **Remote Calibration:** Over-the-air calibration updates

### 10.2 Scalability Considerations

- **Additional Sensor Types:** Framework supports easy extension
- **Enhanced Validation:** Multi-level validation mechanisms
- **Cloud Calibration:** Cloud-based calibration management
- **Sensor Networks:** Cross-hub sensor validation and fusion

---

**Document Status:** Final for Implementation Phase  
**Component Dependencies:** Verified against architecture  
**Requirements Traceability:** Complete (SR-DQC, SWR-DQC)  
**Next Review:** After component implementation