3. EXT: Car demo

The code below is a demonstration of a micro:bit-based embedded system that simulates three vehicle subsystems: air conditioning, sound, and lights.

The program provides a menu-driven interface that allows the user to select a subsystem using Button A and demonstrate it using Button B.

Each subsystem is demonstrated using three predefined output levels to simulate different operating settings.

"""
Vehicle Systems Demonstrator

A micro:bit-based embedded system that demonstrates three vehicle subsystems:
air conditioning, sound, and lights.

The program provides a menu-driven interface that allows the user to select
a subsystem using Button A and demonstrate it using Button B. Each subsystem is
demonstrated using three predefined output levels to simulate different
operating settings.

Inputs:
    Button A - Change selected subsystem.
    Button B - Run subsystem demonstration.

Outputs:
    pin0 - Motor/fan output.
    pin1 - buzzer output.
    pin2 - LED output.

The LED display is used to show menu selections, operating levels, and
system status messages.
"""

from microbit import *
import music

# turn off in built speaker so that the in-built speaker does not also play sounds.
speaker.off()

# Constants
SCROLL_SPEED = 70
DEMO_TIME = 4000
DEMO_GAP_TIME = 1000
DISPLAY_INTERVAL = 2000

# Subsystem Data Dictionary
# This maps each option ID to its name and its respective levels/settings
MODULES = {
    1: {
        "name": "AC",
        "type": "analog",
        "pin": pin0,
        "levels": {1: 250, 2: 500, 3: 1023}
    },
    2: {
        "name": "SOUND",
        "type": "sound",
        "pin": pin1,
        "levels": {
            1: {"vol": 155, "bpm": 120, "tune": music.BIRTHDAY},
            2: {"vol": 200, "bpm": 80,  "tune": music.WEDDING},
            3: {"vol": 255, "bpm": 100, "tune": music.FUNERAL}
        }
    },
    3: {
        "name": "LIGHTS",
        "type": "analog",
        "pin": pin2,
        "levels": {1: 250, 2: 500, 3: 1023}
    }
}

# Initialise tracking variables
last_display_time = running_time()
current_module_selected = 1
previous_module_selected = None


def load_animation():
    clocks = [Image.CLOCK12, Image.CLOCK3, Image.CLOCK6, Image.CLOCK9, Image.CLOCK12]
    display.show(clocks, delay=120)
    display.clear()
    sleep(250)


def show_current_option():
    global previous_module_selected, last_display_time

    if (previous_module_selected != current_module_selected
            or running_time() - last_display_time > DISPLAY_INTERVAL):

        # Grab the module name instantly from our dictionary using the key
        current_module_name = MODULES[current_module_selected]["name"]
        display.scroll(current_module_name, SCROLL_SPEED)
        last_display_time = running_time()  # Reset the timer

    previous_module_selected = current_module_selected
    sleep(200)


# Unified demonstration loop
def run_subsystem_demo(module_id):
    module = MODULES[module_id]
    display.scroll('DEMO...', SCROLL_SPEED)

    # Loop through levels 1 to 3
    for level in range(1, 4):
        display.show(level)
        settings = module["levels"][level]

        if module["type"] == "analog":
            # Handles both AC and Lights dynamically
            module["pin"].write_analog(settings)
            sleep(DEMO_TIME)
            module["pin"].write_analog(0)

        elif module["type"] == "sound":
            # Handles sound settings mapping
            set_volume(settings["vol"])
            music.set_tempo(bpm=settings["bpm"])
            music.play(settings["tune"], wait=False, pin=module["pin"])
            sleep(DEMO_TIME)
            music.stop()

        sleep(DEMO_GAP_TIME)

    display.clear()


###################################################################

# Welcome and button hints
music.play("C", pin=pin1)
display.scroll('WELCOME!', SCROLL_SPEED)
load_animation()
display.scroll('MODULE A -> DEMO B', SCROLL_SPEED)
load_animation()

# Main loop
while True:
    show_current_option()

    if button_a.was_pressed():
        current_module_selected += 1
        # Rollover dynamically based on how many elements are in our dictionary
        if current_module_selected > len(MODULES):
            current_module_selected = 1

    if button_b.was_pressed():
        load_animation()

        # Call the unified function passing the current active ID
        run_subsystem_demo(current_module_selected)

        load_animation()
        previous_module_selected = None   # to cause module display to update

    sleep(50)