import board
import analogio
import digitalio
import time

pot = analogio.AnalogIn(board.GP26)

led = digitalio.DigitalInOut(board.GP25) 
led.direction = digitalio.Direction.OUTPUT

N = 16              #CircuitPython rescales the 12-bit ADC to 16-bit
Vmin = 0.0          #Pico ADC minimum
Vmax = 3.3          #Pico ADC reference voltage

sample_timer = time.monotonic()
sample_period = 0.5

#---- (c) convert raw counts -> voltage ----
def countsToVoltage(counts):

    return (counts / (2**N - 1)) * (Vmax - Vmin) + Vmin

#---- (d) convert voltage -> percent
def voltageToPercent(voltage):
    return (voltage - Vmin) * ((100) / (Vmax - Vmin))

while True:
    if time.monotonic() > (sample_timer + sample_period):
        sample_timer = time.monotonic()    
        counts = pot.value
        voltage = countsToVoltage(counts)
        percent = voltageToPercent(voltage)

    # (e) alarm if percent drops below a certain level
        alarm = percent < 10
        if alarm:
            led.value = True
        else:
            led.value = False
    
        print(counts, voltage, percent)   #(a) counts | (c) voltage | (d) percent