Flight Controller

This is the embedded software on the Flight Controller for the project Mjollnir. The Flight Controller is on-board the rocket. The Flight Controller communicates with the ground through a radio link during all phases of the flight

The mission objectives for the Mjollnir project relevant to the electronics are the following:

Primary objectives

• E.PO.1 Monitor the rocket while it is on the launchpad and give a “Go”/”No go” signal
• E.PO.2 Control the rocket while it is on the launchpad
• E.PO.3 Trigger the drogue parachute’s ejection after apogee
• E.PO.4 Trigger the main parachute’s ejection before touchdown
• E.PO.5 Support rocket recovery operations
• E.PO.6 Record video footage from the rocket

Secondary objectives

• E.SO.1 Send real-time telemetry from the rocket
• E.SO.2 Receive & display real-time telemetry from the rocket at the Ground Station as long as the rocket is at a reasonable distance
• E.SO.3 Send real-time video from the rocket
• E.SO.4 Receive & display real-time video from the rocket at the Ground Station as long as the rocket is at a reasonable distance
• E.SO.5 Acquire flight data with more sensors than those deemed “mission-critical”
• E.SO.6 Store all flight data on-board the rocket for further analysis

All of them apply to some extent to the Flight Controller

Table of content

• Description
  • Hardware
  • Software
    • Installation
  • Tests
• Data protocol
• Folder structure

Description

Hardware

The Flight Controller is a single PCB with power management, sensors, radio communication, and driver for the actuators used during the flight.

It has the following features:

• Dual microcontroller (main + backup)
• Low power long range LoRa transceiver
• Telemetry output via serial link (x3)
• GNSS support via serial link (x3)
• Compatible with 10 dof breakout board with MS5611 pressure sensors and MPU9250 IMU (2x)
• Compatible with K type thermocouples (2x)
• Flash memory
• EEDs driver for parachute ejection, with ESD protection + visual and audible warning (2x)
• RGB leds to display the board status
• Serial link to FPV transmitter
• CAN Bus

A more detailed description of the hardware is given in doc/hardware_description.md

Software

This repository uses PlatformIO as the development tool for the two microcontrollers on the Flight Controller.

Installation

1. Install PlatformIO Core or PlatformIO IDE on your computer
2. Clone this repository
3. [Linux] install udev rules

Tests

See test/

Data protocol

The protocol to communicate between the Ground Station and the Rocket is detailed in doc/data_protocol

Folder structure

.
├── doc/
│   ├── img/
│   ├── diagrams/
│   ├── sources
│   |   └── flight_controller_v1.0.pdf
│   ├── data_protocol.md
│   └── hardware_description.md
├── include/
│   ├── hardware_definition_nano.h
│   └── hardware_definition_teensy.h
├── src/                                    // Code folder
│   └── test_companion_teensy.cpp           // Use with hardware_test_teensy
├── test/                                   // Unit tests
│   ├── hardware_test_nano/
│   ├── hardware_test_teensy/
│   └── README.md                           // Documentation for the tests
├── env_nano.ini                            // Extra platformIO config
├── env_teensy.ini                          // Extra platformIO config
├── LICENSE
├── platformio.ini                          // PlatformIO config
└── README.md                               // This file