from machine import Pin, I2C, ADC
from lcd_api import LcdApi
from i2c_lcd import I2cLcd
from time import sleep

# I2C setup
i2c = I2C(0, sda=Pin(21), scl=Pin(22), freq=100000)
lcd = I2cLcd(i2c, 0x27, 2, 16)

# Potentiometer setup
pot = ADC(Pin(33))
pot.width(ADC.WIDTH_9BIT)   # 0–511
pot.atten(ADC.ATTN_11DB)    # 0–3.3V

while True:
    a = pot.read()
    voltage = (a / 511) * 3.3   # convert ADC value to voltage

    # Show voltage on LCD
    lcd.clear()
    lcd.move_to(0, 0)
    lcd.putstr("Voltage:")
    lcd.move_to(0, 1)
    lcd.putstr("{:.2f} V".format(voltage))

    # Backlight control (ON/OFF)
    if voltage > 1.5:   # threshold value
        lcd.backlight_on()
    else:
        lcd.backlight_off()

    sleep(0.3)