from machine import Pin,ADC
from utime import sleep

led=[Pin(4,Pin.OUT),Pin(5,Pin.OUT),
     Pin(6,Pin.OUT),Pin(7,Pin.OUT)]
pot=ADC(Pin(26))
while 1:
    val=pot.read_u16()
    timing=0.1+(val/65535*2.00)
    print("delay:",timing,"sec")    
    for i in range(4):
        led[i].off()
    led[0].on()
    sleep(timing)
    for i in range(4):
        led[i].off()
    led[1].on()
    sleep(timing)
    for i in range(4):
        led[i].off()
    led[2].on()
    sleep(timing)
    for i in range(4):
        led[i].off()
    led[3].on()
    sleep(timing)