# ASF Sensor Hub – Industrial Gap Resolution & Architecture Proposal

**Target Platform:** ESP32-S3  
**SDK:** ESP-IDF v5.4  
**Domain:** Industrial / Agricultural Automation (Smart Poultry Farm)

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## 1. Introduction

This document provides a **comprehensive proposal to close the identified system gaps** in the ASF Sensor Hub design.  
The focus is on **industrial-grade reliability, security, maintainability, and scalability**, aligned with best practices used in commercial automation and IoT systems.

The solutions proposed here are **technology-backed**, **ESP32-S3–aware**, and suitable for **long-term field deployment in harsh farm environments**.

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## 2. Communication Architecture

### 2.1 Selected Technologies Overview

| Layer | Technology |
|-----|-----------|
| Physical / Link | Wi-Fi 802.11n (2.4 GHz) |
| Messaging | MQTT |
| Security | TLS 1.2 (Mutual Authentication) |
| Peer-to-peer | ESP-NOW |
| Payload Encoding | CBOR |

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### 2.2 Wi-Fi 802.11n (2.4 GHz)

#### Background
Wi-Fi 802.11n at 2.4 GHz is the **most widely supported industrial wireless standard** for embedded devices.  
It offers a good balance between:
- Range
- Penetration through farm structures
- Throughput (sufficient for OTA updates)

#### Why Chosen
- Native support on ESP32-S3
- Existing farm infrastructure compatibility
- Mature ESP-IDF drivers
- High data rate for OTA firmware updates

#### How It Works
The Sensor Hub connects to a local Access Point and establishes a persistent TCP/IP connection to the Main Hub or Edge Gateway.

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### 2.3 MQTT (Message Queuing Telemetry Transport)

#### Background
MQTT is a **lightweight publish/subscribe protocol** designed specifically for unreliable networks and constrained devices.

#### Why Chosen
- Store-and-forward messaging
- Built-in keepalive mechanism
- QoS levels for delivery guarantees
- Massive industrial adoption (SCADA, IIoT)

#### How It Works
- Sensor Hub publishes data to topic hierarchies
- Main Hub subscribes to relevant topics
- Configuration and commands flow in reverse direction

**Example Topic Structure:**