433MHz Security Linkage System

Three-layer build: 433MHz terminals, Flutter app and an IoT backend

Project Overview

433MHz security linkage system delivered across all three layers. Embedded side: STC32G128K running FreeRTOS drives the 433MHz terminals, with a TXW82x SDK IPC/FPV camera and LCD/OLED status display. Mobile side: a Flutter application for iOS and Android covering device pairing, WiFi provisioning, live video, alarm push and arming control. Backend: a NestJS service with PostgreSQL, Redis, an EMQX MQTT broker and ZLMediaKit for media streaming.

Technical Challenges

Keeping 433MHz sub-GHz terminals, an IP camera and a phone app in sync through one backend, with live video and alarm push both arriving reliably.

Solution

STC32G128K on FreeRTOS manages the 433MHz terminals; TXW82x SDK drives the IPC/FPV camera; LCD/OLED shows local status. The Flutter app pairs devices over QR provisioning with WiFi scanning, plays RTSP/HLS streams through VLC, and receives alarm push. A NestJS backend with TypeORM over PostgreSQL handles auth (JWT), device and alarm state, with Redis for caching, EMQX as the MQTT broker for device messaging and ZLMediaKit for stream relay, all orchestrated with Docker Compose.

Key Highlights

Flutter

NestJS

MQTT

STC32G128K

RTSP

Technology Stack

STC32G128K

FreeRTOS

433MHz RF

TXW82x SDK

LCD/OLED

WiFi

Flutter

iOS

Android

go_router

provider

dio

RTSP/HLS

QR Provisioning

WiFi Scan

Alarm Push

NestJS

TypeScript

TypeORM

PostgreSQL

Redis

EMQX