from picozero import Button
from utime import sleep, ticks_ms

entrada = Button(15,pull_up=True)
tiempoA = 0;
switch = False;
periodo = 0;
rpm = 0
while True:
    t = ticks_ms()
    if entrada.is_pressed and switch==False:
        periodo = t-tiempoA
        tiempoA = t
        rpm = (1000/periodo)*60
        print(rpm)
        switch = True;
       

    if entrada.is_pressed == False:
        switch = False;
    #sleep(0.1)