MicroPython OOP Pi Pico Mini Project

This repository is a series of introduction tasks to teach students the basics of Pi Pico and common mechatronic components. Then students will create a mini OOP based project to explicitly teach Object Oriented Paradigm (OOP) programming concepts specifically in the microcontroller context.

Students will be recreating a model of the pedestrian crossing on Unwins Bridge Road out the front of Tempe High School.

Introduction to Pi Pico & Common Mechatronic Commonents

Projects

1. Connect and control a LED
2. Connect a digital sensor that controls the LEDs
3. Connect a analog sensor that controls the LEDs
4. Control the brightness of the LED with Pulse Width Modulation
5. Connect and control a servo motor
6. Connect and read a ultrasonic sensor use it to control the servo motor
7. Connect and control a I2C 16x2 LCD Display

Components

• Breadboard
• Jumper leads
• Pi Pico
• 1x LED
• 1x 130Ω resistors
• 1x Potentiometer or analog sensor
• 1x Momentary switch or digital sensor
• 1x Servo motor
• 1x Ultrasonic sensor
• 1x 2IC 16x2 LCD Display

Pin Allocation

Pin
GP0	SDA
GP1	SCL
GP4	Keyboard Interrupt
GP10	Servo Motor Signal
GP11	Ultrasonic Echo Signal
GP12	Ultrasonic Trig Signal
GP13	Digital Sensor Signal
GP15	External LED
GP25	Inbuilt LED
GP26	Analog Sensor Signal
AGND	Analog Ground
GND	Ground
3V3	3V Power
VBUS	5V Power

OOP Mini Project

From the above real world control system we will model:

• Overloading and overriding polymorphism
• Inheritance, multilevel inheritance and multiple class inheritance
• Abstraction
• Decomposition and composition
• Generalisation
• Encapsulation
• Object instantiation, objects as instance variables

Wire your system

Components

• Breadboard
• Jumper leads
• Pi Pico
• 1x Momentary switch
• 5x LED
• 1x Piezo buzzer
• 5x 130Ω resistors

Pin allocation

Pin
GP3	Red LED
GP4	Keyboard Interrupt
GP5	Amber LED
GP6	Red LED
GP17	Flashing Green LED
GP19	Flashing Red LED
GP22	Button signal
GP27	Piezo Buzzer
GND	Circuit Ground
3V3	Button logic voltage

UML Diagram

classDiagram
    PIN <|-- Button : Inheritance
    PIN <|-- Led_Light : Inheritance
    PWM <|-- Buzzer : Inheritance
    Led_Light <|-- Flashing_Light : Inheritance
    Buzzer <|-- Flashing_Light : Inheritance
    Button --* Pedestrian_Crossing : Composition
    Led_Light --* Pedestrian_Crossing : Composition
    Flashing_Light --* Pedestrian_Crossing : Composition
    class PIN{

    }
    class Led_Light{
        obj Servo
        get_pos()
        set_rot_cw(count)
        set_rot_ccw(count)
    }
    class Flashing_Light{
        obj Servo
        int start_angle
        int min_set_angle
        int max_set_angle
        get_angle()
        set_angle(angle)
    }
    class Button{
        obj Servo
        int open_angle
        int closed_angle
        bool claw_state
        set_open()
        set_closed()
        get_state()
    }
    class Pedestrian_Crossing{
        obj Claw
        obj Base
        obj Elbow
        obj Elbow
        pick_cube()
        place_cube()
    }

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Note

Inheritance and association labels are note required in a UML diagram but have been added for understanding.

Versions

Version	Notes
v01.py	Basic "Blink" Program (the Hello World of mechatronics).
v02.py	Test wiring and use basic methods from parent Pin class.
v03.py	Implement a child class of MicroPython Pin class for the traffic lights, demonstrating Inheritance and Polymorphism.
v04.py	Move the Led_Light class to a separate file, demonstrating abstraction.
v05.py	Write a Button class and test it by instantiating it and controlling the red_light instance of the Led_Light class.
v06.py	Implement a Event Trigger for when the button has been pressed.
v07.py	Demo code only of Multiple Inheritence.

MicroPython_OOP_Pi_Pico_Mini_Project_Source and MicroPython_OOP_Pi_Pico_Mini_Project_Template by Ben Jones is licensed under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International