MiniSat RTOS Project

This project is part of a training program for the Potiguar Rocket Design team. It serves as the foundational codebase for a real-time mini-satellite (CubeSat), built to evolve and scale over time. The system is developed on the ESP32 platform, leveraging the FreeRTOS real-time operating system to handle concurrent tasks efficiently.

Core Features

• Real-Time Operating System (RTOS): Utilizes FreeRTOS to manage multiple tasks, ensuring predictable and timely execution, which is critical for satellite operations.
• Sensor Integration: Interfaces with an MPU6050 (Inertial Measurement Unit) and a BMP180 (Barometric Pressure Sensor) to collect essential flight data.
• Multitasking Architecture:
  • Acquisition Task: A high-frequency task dedicated to reading data from the MPU6050 (accelerometer, gyroscope) and BMP180 (temperature, pressure, altitude) at a rate of 100Hz.
  • Telemetry Task: A lower-frequency task responsible for processing the collected data and sending it to the serial monitor for ground monitoring at a rate of 10Hz.
• Inter-Task Communication: Employs a FreeRTOS queue (sensor_queue) as a thread-safe buffer to reliably pass data from the high-frequency acquisition task to the telemetry task.

Hardware Components

• ESP32 Development Board
• MPU6050 Accelerometer and Gyroscope Module
• BMP180 Temperature and Barometric Pressure Module

Software & Libraries

• PlatformIO IDE
• Arduino Framework
• FreeRTOS.h: Core library for the FreeRTOS kernel.
• Adafruit_MPU6050.h: Driver for the MPU6050 sensor.
• Adafruit_BMP085.h: Driver for the BMP180 sensor (compatible with BMP085).

Project Structure

The codebase is organized into two primary tasks:

1. task_acquisition: This task runs every 10 milliseconds (100Hz). Its sole responsibility is to poll the MPU6050 and BMP180 sensors, package the readings into a SatelliteData_t struct, and send this data packet to the sensor_queue.
2. task_telemetry: This task waits for data to become available in the sensor_queue. Upon receiving a data packet, it formats the information and prints it to the serial port every 100 milliseconds (10Hz), simulating a telemetry downlink.

Future Development

This project is the starting point for a more complex CubeSat system. Future expansions will build upon this RTOS foundation, adding more advanced capabilities such as:

• Data logging to an SD card
• Radio communication (LoRa/RF)
• Attitude determination and control algorithms
• Power management systems

This incremental development approach allows team members to learn and contribute to a growing, mission-oriented project.