Free Software and Documentation for Comma Three Self Driving Car AI Hardware.
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Uh Oh

uhoh --- Notes, docs, scripts for Comma AI Three devkit.

Comma Three AI is hardware to connect to a vehicle for use with free software openpilot AI for "self-driving" cars.


See docs/ directory for more info.


The default OpenPilot setup requires having accounts with proprietary services. This can be worked around.

Setup SSH Without Proprietary Service on Comma Three

Here is HOWTO connect to a Comma Three device without using proprietary services.

The official CommaAI SSH wiki docs are here, but they note they are not for the current version of OpenPilot:

The CommaAI proxy that OpenPilot uses is, sadly, github. This is to be avoided. Another set of docs here:

The above docs are reference, but not how it will be performed below. The hostname used will be tici as that is what the device is named upstream.

This is most easily done with a laptop or similar on the same wifi network as the Comma Three.

This needs to be done on a new device, or a device that has been reset to factory shipping. When the device boots up, go through all the initial steps to get it connected to the Internet via wifi. Stop at the step that reads Choose Software to Install.

At this point, the Comma Three is on the wifi network, and SSH is running with a SHARED ROOT SSH KEY by default. Get the device's IP address from DHCP logs on the DHCP server (e.g. router/firewall).

On the laptop, set up ~/.ssh/config thusly, using the device's IP from DHCP in place of example below. Either port 22 or port 8022 can be used, the device's SSH config has it listening on both:

Host tici
	User comma
	Identityfile ~/.ssh/key.pem
	Port 22

You need to get that SHARED ROOT SSH KEY from github to log into the account:

wget -O ~/.ssh/key.pem

Then make sure your SSH permissions are happy:

chmod 700 ~/.ssh
chmod 600 ~/.ssh/key.pem ~/.ssh/config

Once that is set up, you should be able to SSH into the device thusly:

ssh tici

On the device, add your ssh public keys, at the comma@tici:~$ prompt:

mkdir ~/.ssh
chmod 700 ~/.ssh/

Copy over laptop keys a variety of ways, such as from the laptop:

scp -p ~/.ssh/ tici:.ssh/authorized_keys

Note: Doing the OpenPilot install removes these keys, apparently.

Notes on SSH keys before OpenPilot is installed:

root@tici:~# grep ^AuthorizedKeysFile /etc/ssh/sshd_config
AuthorizedKeysFile /data/params/d/GithubSshKeys

root@tici:/# ls -l /data/params/
total 4
lrwxrwxrwx 1 comma comma   18 Feb  4 23:52 d -> /data/params/d_tmp
drwxr-xr-x 2 comma comma 4096 Feb  4 23:52 d_tmp

root@tici:~# cat /data/params/d_tmp/GithubSshKeys
from=",," ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC+iXXq30Tq+J5NKat3KWHCzcmwZ55nGh6WggAqECa5CasBlM9VeROpVu3beA+5h0MibRgbD4DMtVXBt6gEvZ8nd04E7eLA9LTZyFDZ7SkSOVj4oXOQsT0GnJmKrASW5KslTWqVzTfo2XCtZ+004ikLxmyFeBO8NOcErW1pa8gFdQDToH9FrA7kgysic/XVESTOoe7XlzRoe/eZacEQ+jtnmFd21A4aEADkk00Ahjr0uKaJiLUAPatxs2icIXWpgYtfqqtaKF23wSt61OTu6cAwXbOWr3m+IUSRUO0IRzEIQS3z1jfd1svgzSgSSwZ1Lhj4AoKxIEAIc8qJrO4uymCJ public

Other keys of note. The /data dir is read-write, but /etc is read-only. So it looks like it is doing an overlay with rw data from here, for example with the SSH keys:

root@tici:~# ls -l /data/etc/ssh/
total 32
-rw------- 1 root root 1385 Feb  4 23:52 ssh_host_dsa_key
-rw-r--r-- 1 root root  599 Feb  4 23:52
-rw------- 1 root root  505 Feb  4 23:52 ssh_host_ecdsa_key
-rw-r--r-- 1 root root  171 Feb  4 23:52
-rw------- 1 root root  399 Feb  4 23:52 ssh_host_ed25519_key
-rw-r--r-- 1 root root   91 Feb  4 23:52
-rw------- 1 root root 2590 Feb  4 23:52 ssh_host_rsa_key
-rw-r--r-- 1 root root  563 Feb  4 23:52

Do the install with the URL. Make sure you have an active SSH connection to the device before doing the install, or you will lose SSH access. If you do an install and reboot, you lose SSH access.

Note, after OpenPilot is installed, the /data/params/d/GithubSshKeys file is gone. This file needs to be recreated before closing any SSH sessions, or you will lose access to the device and have to start over. Instead of using the SHARED ROOT SSH KEY used by the Comma Three, use a unique SSH key. On the laptop:

user@laptop:~$ ssh-keygen -t ed25519
Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/user/.ssh/id_ed25519): /home/user/.ssh/id_ed25519-comma
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/user/.ssh/id_ed25519-comma
Your public key has been saved in /home/user/.ssh/
The key fingerprint is:
SHA256:IGVxoSP4EGlmBK4gpCTn8oBlMkoVCN1ENWlfx+RK83c user@laptop
The key's randomart image is:
+--[ED25519 256]--+
|BBOB+.*oo. o.    |
|XO*o.oo+  ..o    |
|O=+ o.+. .o..    |
|++ o o o.. +     |
|. . .   S . . . E|
|             . . |
|                 |
|                 |
|                 |

user@laptop:~$ cat ~/.ssh/ 
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOmI1V0P6dSatrpAgkS9rfmkM1Z1ncAVpHJlLlKrgnTw user@laptop

Then take that pubkey created above, and recreate the /data/params/d/GithubSshKeys file on the device:

from=",," ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOmI1V0P6dSatrpAgkS9rfmkM1Z1ncAVpHJlLlKrgnTw user@laptop

On the screen of the Comma Three, go to:

Setup Icon (top left) --> Network --> Advanced --> Enable SSH

Then you should be able to ssh with the new key setup. Either port 22 or port 8022 can be used. So set up something like this on the laptop in ~/.ssh/config. Call the Host something different than tici so if/when you go back and forth between resets and installs, the SSH is set up for each. golly.

Host openpilot
        User comma
        Port 8022
        Identityfile ~/.ssh/id_ed25519-comma

Then just SSH there from the laptop:

user@laptop:~$ ssh openpilot
                    `t88888d/ h88k 
                       ```    h88l 

Welcome to AGNOS (GNU/Linux 4.9.103+ aarch64)

  System information as of Sat 05 Feb 2022 12:44:08 AM UTC

  System load:  0.23              Temperature:            75.0 C
  Usage of /:   30.5% of 9.78GB   Processes:              586
  Memory usage: 23%               Users logged in:        1
  Swap usage:   0%                IPv4 address for wlan0:

Last login: Sat Feb  5 00:41:30 2022 from

This will survive reboot.

An sshfs mount can also be setup, on laptop:

sudo apt update
sudo apt install sshfs

mkdir -p ~/mnt

sshfs openpilot:/ ~/mnt/

ls -lh ~/mnt/


This repository, documentation, and code is unofficial, unaffiliated with Comma AI.



Copyright (C) 2022, Jeff Moe