Skip to content

Ground Station

Archived 2024–2025 hardware guide. Confirm current hardware and requirements with the leads. SSH safety guidance was corrected on October 8, 2026.

The ground station is a raspberry pi with an HC-12.

Connect the HC-12 to pins in the image below no need for the set pin, set the channel using the flight computer. Screenshot 2024-04-24 at 11 18 13 PM

Raspberry Pi Set Up

Flash and Connect to Raspberry Pi

  1. Download Raspberry Pi Imager
  2. Select RASPBERRY PI OS LITE (64-BIT)
  3. Use Imager's customization settings to set a unique hostname and username. Enable SSH with public-key authentication and add each authorized member's public key. Keep private keys and passwords private; never post them in Discord or this repository. See Raspberry Pi's SSH documentation.
  4. Plug in SD card, select it, click write.
  5. Plug in Pi to network, and connect computer to same network
  6. Verify the Pi's SSH host-key fingerprint through a trusted local console or the device administrator before accepting it. Connect using your own key: ssh username@hostname.local.

Enable the pins on the raspberry pi

sudo raspi-config You should see this Screenshot 2024-04-24 at 11 32 10 PM Select 3 Interface options Screenshot 2024-04-24 at 11 33 03 PM select I5 Serial Port Screenshot 2024-04-24 at 11 33 38 PM Select No dont enable ssh over serial Screenshot 2024-04-24 at 11 33 55 PM Select yes enable serial port hardware to be enabled

It should look like this Screenshot 2024-04-24 at 11 34 24 PM

Select finish, and reboot it now, you'll have to ssh into it again Screenshot 2024-04-24 at 11 34 49 PM

Install a few things in Linux

  1. First familiarize youself with ls, ls -al, cd, mkdir, rm, rm -r, sudo
  2. Install git sudo apt install git
  3. Clone repo git clone https://github.com/marstmu/groundstation.git
  4. Install python library sudo apt install python3-serial
  5. cd into groundstation cd groundstation
  6. Run gs.py with python python gs.py

Tips

If it says something like this while trying to SSH: ssh-remote-host-identification-has-changed Stop and verify why the key changed. From a trusted console on the Pi, an administrator can show its Ed25519 host-key fingerprint with ssh-keygen -lf /etc/ssh/ssh_host_ed25519_key.pub. Compare it with the fingerprint shown by SSH.

Only after independently confirming a legitimate change (for example, an authorized re-image), remove the entry for that specific hostname with ssh-keygen -R hostname.local, then reconnect and verify the fingerprint. If you connected by IP address, use that exact IP instead. Never delete the entire known_hosts file or bypass host-key checking.

Reference: OpenSSH's ssh-keygen manual.