# **ASF Sensor Hub**

## **Feature Engineering Specification**

## **Sensor Data Acquisition Features**

## **1\. Feature Overview**

### **Feature Name**

Sensor Data Acquisition Features

### **Feature ID**

FEAT-DAQ

### **Subsystem**

ASF Sensor Hub (Sub-Hub)

### **Target Platform**

ESP32-S3–based embedded system

### **Scope**

This feature defines the capabilities of the Sensor Hub related to:

*   Environmental sensor data acquisition
    
*   Local preprocessing and filtering
    
*   Timestamping and preparation of sensor data for persistence and communication
    

This feature **does NOT include**:

*   Main Hub processing
    
*   Cloud analytics
    
*   Control logic
    
*   OTA, diagnostics, or persistence mechanisms (referenced only as dependencies)
    

## **2\. Purpose and Engineering Rationale**

Modern poultry farm automation systems require **high-resolution, reliable, and time-correlated environmental data** to enable:

*   Accurate environmental control
    
*   Early fault detection
    
*   Advanced analytics and machine learning
    

The Sensor Data Acquisition feature ensures:

*   Deterministic sensor sampling
    
*   Noise-resilient measurements
    
*   Temporal traceability of data
    
*   Decoupling of acquisition from communication and control
    

This aligns with **distributed intelligence principles** used in leading international poultry automation systems.

## **3\. Feature Decomposition**

The Sensor Data Acquisition feature is decomposed into the following sub-features:

<figure class="table op-uc-figure_align-center op-uc-figure"><table class="op-uc-table"><thead class="op-uc-table--head"><tr class="op-uc-table--row"><th class="op-uc-table--cell op-uc-table--cell_head"><p class="op-uc-p">Sub-Feature ID</p></th><th class="op-uc-table--cell op-uc-table--cell_head"><p class="op-uc-p">Name</p></th></tr></thead><tbody><tr class="op-uc-table--row"><td class="op-uc-table--cell"><p class="op-uc-p">F-DAQ-01</p></td><td class="op-uc-table--cell"><p class="op-uc-p">Multi-Sensor Data Acquisition</p></td></tr><tr class="op-uc-table--row"><td class="op-uc-table--cell"><p class="op-uc-p">F-DAQ-02</p></td><td class="op-uc-table--cell"><p class="op-uc-p">High-Frequency Sampling and Local Filtering</p></td></tr><tr class="op-uc-table--row"><td class="op-uc-table--cell"><p class="op-uc-p">F-DAQ-03</p></td><td class="op-uc-table--cell"><p class="op-uc-p">Timestamped Sensor Data Generation</p></td></tr></tbody></table></figure>

## **4\. Functional Description**

### **4.1 F-DAQ-01: Multi-Sensor Data Acquisition**

#### **Description**

The Sensor Hub acquires environmental data from multiple heterogeneous sensors connected to dedicated hardware interfaces.

#### **Supported Sensor Types**

*   Temperature
    
*   Relative Humidity
    
*   Carbon Dioxide (CO₂)
    
*   Ammonia (NH₃)
    
*   Volatile Organic Compounds (VOC)
    
*   Particulate Matter (PM)
    
*   Light Intensity
    

Each sensor:

*   Is mapped to a predefined hardware slot
    
*   Has a dedicated driver abstraction
    
*   Can be independently enabled or disabled
    

#### **Key Characteristics**

*   Concurrent sensor handling
    
*   Modular sensor driver architecture
    
*   Runtime awareness of sensor presence
    

### **4.2 F-DAQ-02: High-Frequency Sampling and Local Filtering**

#### **Description**

For each enabled sensor, the system performs multiple raw readings per acquisition cycle and applies a local filtering mechanism to produce a single representative value.

#### **Sampling Behavior**

*   Each sensor is sampled **N times per cycle** (default: 10)
    
*   Sampling occurs within a bounded time window
    
*   Sampling frequency is configurable via Machine Constants
    

#### **Filtering Behavior**

*   Filtering is executed locally on the Sensor Hub
    
*   Filtering algorithms are abstracted and replaceable
    
*   Examples (non-exhaustive):
    
    *   Moving average
        
    *   Median filter
        
    *   Outlier rejection
        

#### **Objective**

*   Reduce sensor noise
    
*   Improve data stability
    
*   Avoid propagating raw sensor jitter upstream
    

### **4.3 F-DAQ-03: Timestamped Sensor Data Generation**

#### **Description**

Each processed sensor value is associated with a timestamp generated by the Sensor Hub.

#### **Timestamp Characteristics**

*   Generated after filtering completion
    
*   Represents the effective measurement time
    
*   Based on system time (RTC or synchronized clock)
    

#### **Sensor Data Record**

Each record includes:

*   Sensor ID
    
*   Sensor type
    
*   Filtered value
    
*   Unit of measurement
    
*   Timestamp
    
*   Data validity status
    

## **5\. Operational Flow**

### **Normal Acquisition Cycle**

1.  Detect enabled sensors
    
2.  Initialize sensor drivers (if not already active)
    
3.  Perform high-frequency sampling per sensor
    
4.  Apply local filtering
    
5.  Generate timestamp
    
6.  Create sensor data record
    
7.  Forward data to:
    
    *   Data Persistence component
        
    *   Communication component (on request)
        

## **6\. Constraints and Assumptions**

### **Constraints**

*   Sensor acquisition must not block system-critical tasks
    
*   Sampling and filtering must complete within a bounded cycle time
    
*   Memory usage must be deterministic
    

### **Assumptions**

*   Sensor presence detection is handled by a separate feature
    
*   Time synchronization is provided by another system component
    
*   Storage and communication are decoupled from acquisition
    

## **7\. Architecture Diagram (PlantUML)**

### **7.1 Sensor Hub Component Diagram**

```mermaid
graph TD
    subgraph "Sensor Hub"
        SD["Sensor Drivers"] --> SE["Sampling Engine"]
        SE --> FE["Filtering Engine"]
        FE --> TS["Timestamp Service"]
        TS --> DB["Sensor Data Buffer"]
    end
    SD -->|"raw samples"| SE
    SE -->|"sampled data"| FE
    FE -->|"filtered value"| TS
    TS -->|"timestamped record"| DB
```

### **7.2 Acquisition Cycle Sequence Diagram**

```mermaid
sequenceDiagram
    participant S as Sensor Driver
    participant SE as Sampling Engine
    participant FE as Filtering Engine
    participant TS as Timestamp Service
    S ->> SE: read()
    loop N samples
        SE ->> S: sample()
    end
    SE ->> FE: raw sample set
    FE ->> TS: filtered value
    TS ->> FE: timestamp
```

## **8\. Formal System SHALL Requirements**

### **8.1 Requirement Style**

*   Each requirement uses **“The system shall …”**
    
*   Each requirement has a unique ID
    
*   Requirements are atomic and testable
    

### **8.2 Requirements List**

#### **Multi-Sensor Acquisition**

*   **REQ-DAQ-001**  
    The system shall support acquisition of data from multiple environmental sensor types simultaneously.
    
*   **REQ-DAQ-002**  
    The system shall provide a dedicated software driver abstraction for each supported sensor type.
    
*   **REQ-DAQ-003**  
    The system shall acquire sensor data only from sensors detected as present and enabled.
    

#### **High-Frequency Sampling &amp; Filtering**

*   **REQ-DAQ-004**  
    The system shall sample each enabled sensor multiple times within a single acquisition cycle.
    
*   **REQ-DAQ-005**  
    The system shall apply a local filtering mechanism to raw sensor samples to produce a single representative value.
    
*   **REQ-DAQ-006**  
    The system shall allow configuration of sampling count and filtering parameters via system configuration data.
    

#### **Timestamped Data Generation**

*   **REQ-DAQ-007**  
    The system shall associate each processed sensor value with a timestamp.
    
*   **REQ-DAQ-008**  
    The system shall generate timestamps after completion of filtering.
    
*   **REQ-DAQ-009**  
    The system shall include sensor identifier, sensor type, value, unit, timestamp, and validity status in each sensor data record.
    

## **9\. Feature-to-Requirement Traceability**

<figure class="table op-uc-figure_align-center op-uc-figure"><table class="op-uc-table"><thead class="op-uc-table--head"><tr class="op-uc-table--row"><th class="op-uc-table--cell op-uc-table--cell_head"><p class="op-uc-p">Feature ID</p></th><th class="op-uc-table--cell op-uc-table--cell_head"><p class="op-uc-p">Requirement IDs</p></th></tr></thead><tbody><tr class="op-uc-table--row"><td class="op-uc-table--cell"><p class="op-uc-p">F-DAQ-01</p></td><td class="op-uc-table--cell"><p class="op-uc-p">REQ-DAQ-001, REQ-DAQ-002, REQ-DAQ-003</p></td></tr><tr class="op-uc-table--row"><td class="op-uc-table--cell"><p class="op-uc-p">F-DAQ-02</p></td><td class="op-uc-table--cell"><p class="op-uc-p">REQ-DAQ-004, REQ-DAQ-005, REQ-DAQ-006</p></td></tr><tr class="op-uc-table--row"><td class="op-uc-table--cell"><p class="op-uc-p">F-DAQ-03</p></td><td class="op-uc-table--cell"><p class="op-uc-p">REQ-DAQ-007, REQ-DAQ-008, REQ-DAQ-009</p></td></tr></tbody></table></figure>