Editing Ultrasonic Sensor HC-SR04

= Description =
The HC-SR04 is an ultrasonic distance sensor that can measure distances from 2cm to 400cm.
It sends out an ultrasound signal and detects the echo. By measuring the time you can calculate the distance.

[[File:Ultra1.JPG|300px]]

more details:
* https://randomnerdtutorials.com/complete-guide-for-ultrasonic-sensor-hc-sr04/
* https://cdn.sparkfun.com/datasheets/Sensors/Proximity/HCSR04.pdf

= How to connect it electrically =

[[File:Stepper-c.JPG|x420px]]


= Required Module and Files =
* We use '''[https://www.sketching-with-hardware.org/files/hcsr04.py hcsr04.py]'''
* this is downloaded from https://github.com/rsc1975/micropython-hcsr04
* the original file is at https://github.com/rsc1975/micropython-hcsr04/blob/master/hcsr04.py


= How to control it in MicroPython =

<syntaxhighlight lang="python" line='line'>
from hcsr04 import HCSR04
from time import sleep

sensor = HCSR04(trigger_pin=12, echo_pin=14)
sleep(1)
i=0

while True:
  distance = sensor.distance_cm()
  print(i, ': Distance:', distance, 'cm')
  i=i+1
  sleep(0.5)

</syntaxhighlight>




= Related Tutorial Videos =
<youtube>PJdDUZWeIDs</youtube>
@@ Line 3: / Line 3: @@
 It sends out an ultrasound signal and detects the echo. By measuring the time you can calculate the distance.
-[[File:Hc-sr04-1.JPG|x300px]]
+[[File:Ultra1.JPG|300px]]
-[[File:Ultra1.JPG|x300px]]
 more details:
@@ Line 12: / Line 11: @@
 = How to connect it electrically =
-[[File:Hc-sr04-e.JPG|x420px]]
+[[File:Stepper-c.JPG|x420px]]
 = Required Module and Files =
@@ Line 43: / Line 43: @@
 = Related Tutorial Videos =
 <youtube>PJdDUZWeIDs</youtube>
-= Background =
-connecting it to the ESP8266 and reading the signal in without a library/module.
-Connect Trig to Pin5 and Echo to Pin4 of the ESP8266.
-[[File:Hc-03.JPG|x300px]]
-[[File:Hc04-03.JPG|x300px]]
-[[File:Hc-sr04-1.JPG|x300px]]
-<syntaxhighlight lang="python" line='line'>
-import machine
-import utime
-while True:
-  trig=machine.Pin(5, machine.Pin.OUT)
-  trig.off()
-  utime.sleep_us(2)
-  trig.on()
-  utime.sleep_us(10)
-  trig.off()
-  echo=machine.Pin(4, machine.Pin.IN)
-  while echo.value() == 0:
-    pass
-  t1 = utime.ticks_us()
-  while echo.value() == 1:
-    pass
-  t2 = utime.ticks_us()
-  cm = (t2 - t1) / 58.0
-  print(cm)
-  utime.sleep(2)
-</syntaxhighlight>