HEYU: Can’t open tty line. Check the permissions.

I occasionally get this error when trying to run a heyu command from CLI. This should fix your problem:

(As root)

chmod 777 /dev/ttyS0


  1. Not an elegant solution at all. So instead of getting proper permissions, getting the right key, you just remove the lock to your door all together, so that everybody can enter. Please remember that this is OK for a temporary solution, but that any user on your server, a hacker or something, no matter how low a user can control your heyu and therefore your home automation.

  2. Thanks! That did it!!
    – rob

  3. Thanks for the info! This helped 🙂


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