import machine
import time

#######################################
# Pin and constant definitions
#######################################
ANALOG_PIN = 26  # ADC pin for analogue components
BUTTON_PIN = 16  # Pushbutton pin
DISPLAY_PINS = [0, 1, 2, 3, 4, 5, 6]  # 7-segment display segments (a to g)
DP_PIN = 7  # Decimal point pin
DIGIT_PINS = [8, 9, 10, 11]  # Display digit select lines (DIG1 to DIG4)

# Seven-segment display digits (0-9), in binary for common cathode display
DIGIT_VALUES = [
    0b00111111,  # 0
    0b00000110,  # 1
    0b01011011,  # 2
    0b01001111,  # 3
    0b01100110,  # 4
    0b01101101,  # 5
    0b01111101,  # 6
    0b00000111,  # 7
    0b01111111,  # 8
    0b01101111   # 9
]

#######################################
# Global variables
#######################################
last_button_press_time = 0
current_voltage_mv = 0

#######################################
# Function definitions
#######################################

# Function to read the ADC pin and
# convert the digital value to a voltage level in the 0-3.3V range
def read_analogue_voltage(pin):
    global current_voltage_mv
    sum_values = 0
    num_samples = 16  # Number of samples to average
    
    for _ in range(num_samples):
        sum_values += pin.read_u16()  # Read ADC value as a 16-bit unsigned integer
    
    average_value = (sum_values / num_samples) * 3.3 / 65535  # Convert ADC reading to voltage 
    voltage_mv = int(average_value * 1000)  # Convert to millivolts and then to integer 
    current_voltage_mv = voltage_mv  # Update global voltage value
    
    # Print voltage to console
    print("Voltage: {} mV".format(voltage_mv))

# Function to display the voltage on the seven-segment display
def display_voltage(voltage_mv):
    if voltage_mv > 9999:
        voltage_mv = 9999
    elif voltage_mv < 0:
        voltage_mv = 0
    
    # Convert voltage to individual digits
    digit4 = voltage_mv % 10
    voltage_mv //= 10
    digit3 = voltage_mv % 10
    voltage_mv //= 10
    digit2 = voltage_mv % 10
    voltage_mv //= 10
    digit1 = voltage_mv % 10

    # Display digit1 on seven-segment display with DP on
    display_digit(digit1, 0)
    machine.Pin(DP_PIN, machine.Pin.OUT).value(1)  # Set DP pin to HIGH for digit1
    time.sleep(0.005)

    # Turn off DP for all other digits
    machine.Pin(DP_PIN, machine.Pin.OUT).value(0)  # Set DP pin to LOW for remaining digits

    # Display remaining digits
    display_digit(digit2, 1)
    time.sleep(0.005)
    display_digit(digit3, 2)
    time.sleep(0.005)
    display_digit(digit4, 3)
    time.sleep(0.005)

# Function to display a digit on the common cathode seven-segment display
def display_digit(digit_value, digit_index):
    for pin in DIGIT_PINS:
        machine.Pin(pin, machine.Pin.OUT).value(1)  
    
    # Set segments for the digit value
    segments = DIGIT_VALUES[digit_value]
    for i, seg_pin in enumerate(DISPLAY_PINS):
        machine.Pin(seg_pin, machine.Pin.OUT).value(segments >> i & 1)
    
    machine.Pin(DIGIT_PINS[digit_index], machine.Pin.OUT).value(0)  

# Function to setup GPIO/ADC pins and polling loop
def setup():
    global last_button_press_time

    last_button_press_time = 0

    # Initialize ADC pin and other necessary pins
    adc = machine.ADC(machine.Pin(ANALOG_PIN))
    button = machine.Pin(BUTTON_PIN, machine.Pin.IN, machine.Pin.PULL_UP)

    # Initialize DP pin
    machine.Pin(DP_PIN, machine.Pin.OUT).value(0)  

    while True:
        if button.value() == 0:  
            current_time = time.ticks_ms()
            if current_time - last_button_press_time > 200:  # 200ms debounce time
                read_analogue_voltage(adc)
                last_button_press_time = current_time

        # Continuously refresh the display with the current voltage
        display_voltage(current_voltage_mv)

        time.sleep_ms(10)  

if __name__ == '__main__':
    setup()


#This project is designed to create a system using a Raspberry Pi Pico microcontroller
#to measure and display voltage on a 4-digit seven-segment display.
#It includes functionalities to read analog voltage inputs, debounce a pushbutton for control,
#and dynamically update the display based on user interactions.