from machine import Pin, PWM
import time

ir_led = PWM(Pin("GP18"))
ir_led.freq(38000)
ir_led.duty_u16(0)

def emit_pulse(duration_us):
    ir_led.duty_u16(32768)  # 50% duty cycle
    time.sleep_us(duration_us)
    ir_led.duty_u16(0)      # 0% duty cycle

try:
    while True:
        emit_pulse(200)
        time.sleep_ms(10)
        
        emit_pulse(800)
        time.sleep_ms(10)

except KeyboardInterrupt:
    ir_led.deinit()