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Awais Asghar.
Embedded & IoT2025

FreeRTOS Smart Energy Monitor

STM32F746 tasks compute Vrms, Irms and kWh; an ESP32 pushes it to a cloud dashboard.

A real-time energy monitoring and billing system. Independent FreeRTOS tasks on an STM32F746 handle sensor acquisition from ZMPT101B and ACS712 modules, RMS calculation with DC-offset removal, power and energy computation, and a local display. Processed data goes over UART to an ESP32 that uploads to Firebase for remote monitoring.

Source on GitHub
FreeRTOS Smart Energy Monitor thumbnail

README · rendered from GitHub

FreeRTOS-Based Smart Energy Monitor using STM32

Status Platform MCU RTOS Cloud Language Lisence

Project Overview

This project implements a real-time smart energy monitoring and billing system using the STM32F746 microcontroller and ESP32. The system measures voltage and current, computes RMS values, calculates power and energy consumption, and uploads live data to the Firebase cloud using WiFi. The design follows a FreeRTOS-based multi-task architecture, ensuring deterministic operation and clean separation of responsibilities.

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Key Features

  • Real-time voltage and current measurement
  • RMS calculation with DC offset removal
  • Power and energy (kWh) computation
  • Cloud-based monitoring using Firebase
  • FreeRTOS-based multi-threaded design
  • UART communication between STM32 and ESP32

System Architecture

  • Voltage Sensor (ZMPT101B) → STM32 ADC
  • Current Sensor (ACS712 / INA219) → STM32 ADC
  • STM32F746 → Signal processing + RMS calculation (FreeRTOS)
  • ESP32 → WiFi + Firebase cloud upload
  • UART → Communication between STM32 and ESP32
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Tools and Technologies

  • STM32F746
  • FreeRTOS
  • STM32CubeIDE
  • IAR Embedded Workbench
  • ESP32
  • Arduino IDE
  • Firebase Realtime Database
  • UART Communication
  • C / C++
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Core Implementation

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FreeRTOS Task Design

STM32 (RTOS-based)

  • ADC Sampling Task (High Priority)
  • RMS & Signal Processing
  • UART Transmission Task

ESP32 (Dual-Core FreeRTOS)

  • UART Receive Task
  • Cloud Upload Task
  • Serial Debug Task

Mutexes are used to protect shared data across tasks.

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Hardware Implementation

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Results

  • Stable RMS voltage and current measurement
  • Accurate power and energy computation
  • Live cloud updates every 5 seconds
  • Robust real-time performance using FreeRTOS
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Applications

  • Smart home energy monitoring
  • Industrial power usage tracking
  • Smart metering systems
  • Energy consumption analysis
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Demo Video

https://github.com/user-attachments/assets/38ebc3f2-3e4e-472e-ad77-98723180af24

Team Members

  • Awais Asghar
  • Muhammad Haris
  • Saad Farooq
  • Aneeqa Ur Rehman
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References

  • STM32F746 Reference Manual
  • ESP32 Technical Reference
  • Firebase Realtime Database Documentation
  • FreeRTOS Official Documentation
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License

This project is intended for academic and educational use.

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