In this tutorial we are going to remotely control an Arduino from a python-script

The hardware-components will be modeled in an object-oriented manner to provide a nice and reusable interface

In order to remotely control the Arduino it has to be flashed with a firmware that accepts and executes commands

1 at_commands[] = {
2   {.name= "AT",            .cb= atcb_at},
3   {.name= "AT+SET_OUT",    .cb= atcb_setout},
4   {.name= "AT+SET_IN",     .cb= atcb_setin},
5   …
6   {.name= NULL, .cb=NULL}
7 };

…

The sketch above accepts AT-style commands that can be used to read and write digital pins

Upload the sketch from the previous slide to your Arduino and configure the serial monitor to send a carriage return ␍ and a newline ␊ character at the end of each line, and to use a speed of 115200 Baud

AT+SET_OUT=13
AT+WRITE_HIGH=13

Enter the commands above into the serial monitor to turn on the Arduino on-board LED

The Arduino should acknowledge both commands with an OK and turn on the LED

Study the commands in the at_commands array

find the commands that let you read out the HIGH or LOW state of pin 10

Use a piece of wire to change the state of pin 10

1 duino= Arduino('/dev/ttyACM0')
2 
3 key1= InputPin(duino, 10, True)
4 #led1= OutputPin(duino, 13)

…

The code above contains class definitions that model the connection to an Arduino and its input pins

Change '/dev/ttyACM0' to the name of your serial port, run the program and observe its output

Hint: You can use the Arduino IDE to find the name of your serial port

Write a class OutputPin that, analogous to the class InputPin, models an output pin

The class should provide a method set_state that turns the output on or off

When you are done, uncomment the commented-out lines, to verify that your implementation works as expected

Hint: you can use the interactive commandline to test your implementation python3 -i 16_atuino.py

1 class OutputPin(object):
2     def set_state(self, state):
3         self.arduino.exec_cmd(
4             'WRITE_HIGH' if state else 'WRITE_LOW',
5             self.pin_no
6         )

…