FAQ: How can I adjust the screen brightness of UNIHIKER (Python)?

# UnihikerScreen: A simple class to control the screen (on, off & brightness) of a Unihiker ...

from periphery import PWM

class UnihikerScreen:
    
    PWM_CHIP = 1 # '/sys/class/pwm/pwmchip1/.'
    PWM_CHANNEL = 0 # ./pwm0
    
    MAX_BRIGHTNESS = 0.99 # max. duty cycle
    
    def __init__(self, pwm_chip=PWM_CHIP, pwm_channel=PWM_CHANNEL):
        # Initialize the PWM device
        self.pwm = PWM(pwm_chip, pwm_channel)
        self.pwm.polarity = "normal" # Set polarity to 'normal'
        self.pwm.frequency = 1000  # Set a default frequency (1 kHz)
        self.pwm.enable()
        self._brightness = UnihikerScreen.MAX_BRIGHTNESS 

    def on(self):
        # Set duty cycle to the last set brightness to turn the screen on
        if self._brightness == 0: 
            self._brightness = UnihikerScreen.MAX_BRIGHTNESS
        self.pwm.duty_cycle = self._brightness

    def off(self):
        # Set duty cycle to 0% to turn the screen off
        self.pwm.duty_cycle = 0.0

    def brightness(self, percent):
        # Set the brightness as a percentage (0 to 100)
        if 0 <= percent < 100:
            self._brightness = percent / 100.0
        elif percent == 100:
            self._brightness = UnihikerScreen.MAX_BRIGHTNESS
        else:
            raise ValueError("Brightness percent must be between 0 and 100")
        self.pwm.duty_cycle = self._brightness

    def __del__(self):
        # Clean up the PWM device
        self.pwm.close()

from UnihikerScreen import UnihikerScreen
import time

screen = UnihikerScreen()

# Turn off ...
screen.off()

time.sleep(1)

# Turn back on ...
screen.on()

time.sleep(1)

# Set brightness to 25%  ...
screen.brightness(25)

time.sleep(1)

# Turn off ...
screen.off()

time.sleep(1)

# Turn back on (to 25% brightness) ...
screen.on()

time.sleep(1)