N2-flight-software

Introduction

This repository contains code used for flight software for Nakuja Rocket N2. The following description provides a detailed description of program flow, project structure, library dependencies and/or any other necessary documentation needed to run this code successfully.

Project structure

---

├── data
│   └── flightdata.txt
├── include
│   ├── checkState.h
│   ├── defs.h
│   ├── functions.h
│   ├── kalmanfilter.h
│   ├── logdata.h
│   ├── readsensors.h
│   └── transmitwifi.h
├── lib
│   └── README
├── LICENSE
├── platformio.ini
├── README.md
├── src
│   └── main.cpp
└── test
    └── README

1. Folders Description

Folder	Description
include	Contains header files
lib	Project libraries
src	Contains main.cpp source file run by the flight computer
test	Contains unit test files

2. Files Description

File	Description
defs.h	Contains constants declaration
functions.h	Contains general utility functions and prototype function declarations
logdata.h	code for SD card mounting and logging
checkState.h	Contains state machine logic
kalmanfilter.h	Contains kalman filter for accelerometer values
readsensors.h	Contains code for sensors on board including the MPU,BMP,GPS
transmitwifi.h	Contains WiFi set-up and MQTT code

Flight Logic

The flight program is structured as a state machine with the following states:

State	Description	Waiting for event
0	Pre-Flight Ground	altitude >= 10m AGL
1	Powered Flight
2	Coasting	velocity < 0 to detect apogee
3	Apogee	10m below apogee to deploy parachute
4	Chute Descent	altitude <= 10m AGL
5	Post-flight Ground	No more events

Safe-mode

Proposed safe mode conditions to prevent premature misfires of the parachute ejection system:

1. Ejection system pins are disabled
2. State transitions are locked
3. State is maintained at SAFE_MODE-PREFLIGHT

Flight Mode

In the flight-mode:

1. The parachute ejection system is enabled- any pin being used in the ejection system is enabled
2. State transition flag is enabled

State diagram