Installation

Prerequisites

Raspberry Pi Zero W (or Pi Zero 2 W)
Raspbian / Raspberry Pi OS Lite
Python 3.x
Hardware interfaces enabled: I2C, SPI, UART

Quick Install

Run the install script from the project root:

sudo bash install.sh

This script performs the following:

1. System Update

sudo apt update && sudo apt upgrade -y

2. Python Dependencies

Package	Purpose
`pyyaml`	Configuration file parsing
`psutil`	System metrics (CPU, RAM, disk)
`pyserial`	UART communication with RP2040
`adafruit-circuitpython-rfm9x`	RFM95 LoRa radio driver
`adafruit-circuitpython-rfm69`	RFM69 FSK radio driver
`adafruit-extended-bus`	Extended SPI/I2C bus support
`adafruit-ina219`	INA219 current sensor driver
`watchdog`	File system monitoring for config reload
`pigpio`	Software UART for EPS communication

3. Hardware Interface Configuration

The script enables the following via raspi-config:

I2C — For INA219 solar sensors
SPI — For RFM69/RFM95 radio modules
UART — For RP2040 MCU communication

4. pigpiod Service

The pigpio daemon is required for bit-banged UART to the ATmega328PB EPS:

sudo systemctl enable pigpiod
sudo systemctl start pigpiod

5. Systemd Service

The FSW runs as a systemd service that starts on boot and restarts on failure:

[Unit]
Description=TEMPEST Flight Software
After=multi-user.target pigpiod.service

[Service]
ExecStart=/usr/bin/python /home/ethos/TEMPEST_FSW/main.py
Restart=always
User=ethos

[Install]
WantedBy=multi-user.target

Service Management

# Start the FSW
sudo systemctl start tempest_fsw

# Stop the FSW
sudo systemctl stop tempest_fsw

# Check status
sudo systemctl status tempest_fsw

# View logs
journalctl -u tempest_fsw -f

# Restart after code changes
sudo systemctl restart tempest_fsw

Manual Execution

For development and debugging, run the FSW directly:

# Production mode (requires radio hardware)
python main.py

# CLI development mode (no radio required)
python cli_fsw.py

RP2040 Firmware

The RP2040 Pico runs CircuitPython. To update the firmware:

Hold the BOOTSEL button while connecting the Pico via USB
Copy the CircuitPython .uf2 file to the mounted drive
After reboot, copy code.py to the Pico's CIRCUITPY drive
Install required CircuitPython libraries:
- adafruit_bno055
- adafruit_bmp280

See Sensor MCU for details on the RP2040 firmware.

Directory Structure

TEMPEST_FSW/
├── main.py              # Production FSW (radio mode)
├── cli_fsw.py           # Development FSW (CLI mode)
├── code.py              # RP2040 CircuitPython firmware
├── config.yml           # Radio configuration (live-reloaded)
├── config.yml.bak       # Backup config (restored on startup)
├── install.sh           # Installation script
├── fsw_service.sh       # Systemd service creator
├── capture/             # Image capture directory
├── subsystems/
│   ├── environmental.py # RP2040 UART interface
│   ├── obc.py           # On-board computer functions
│   ├── payload.py       # Camera and image handling
│   ├── solar.py         # INA219 solar panel sensors
│   ├── eps.py           # ATmega328PB EPS interface
│   └── retransmit.py    # Packet retransmission
├── utils/
│   ├── radio.py         # Radio abstraction layer
│   └── display.py       # Console output formatting
├── FSC-GS/              # Ground station web interface
│   ├── index.html
│   ├── styles.css
│   └── scripts/
│       ├── main.js
│       ├── telemetry.js
│       ├── serial-communication.js
│       ├── image-processing.js
│       └── 3d-visualization.js
└── docs/                # This documentation