If you get a /Permission denied/, you have to add your user to the group of the serial port (in this case /dev/ttyACM0).
To check the group of the device:
#+BEGIN_SRC sh
ls -la /dev/ttyACM0
#+END_SRC
Then add your user to the group (in this case the group is dialout and the user is user)
#+BEGIN_SRC sh
sudo usermod -aG dialout user
#+END_SRC
** ESP8266
During the *Week 4*, we used the NodeMCU instead of the Arduino uno, in this case to compile and upload the sketch (in this case we'll use the sketch Test):