Micropython HC-SR04 - ESP8266

_x000D_ _x000D_ I am trying to get the NodeMCU ESP8266 dev board to work with an HC SR04 Ultrasonic Sensor. I keep getting a reading of "0", which is not the reality. I have the ground and 5v pins of the sensor hooked up to a 5v source, and the Echo and Trigger pins on GPIO pin 4 and 5. In theory, everything should be working, but I just keep getting "0". Perhaps there is something wrong with my code? See below: import machine import sys import time time.sleep(1) #Just for everything to settle down while 1: pinTrigger = machine.Pin(5, machine.Pin.OUT) #defining the pins pinEcho = machine.Pin(4, machine.Pin.IN) #defining the pins pinTrigger.high() time.sleep(0.00001) pinTrigger.low() time.sleep(0.5) start = time.time() stop = time.time() while pinEcho ==0: start = time.time() #Starting the time when sending out the signal while pinTrigger ==1: stop = time.time() #Stopping the time when the signal comes back elapsed = stop-start #working out the time. distance = elapsed * 34000 #multiply by speed of sound to get distance distance = distance / 2 #divide by 2 becuase it was there and back print ("Distance : %.1f" % distance) sys.exit() Please help.