text: #!/usr/bin/env python
  #In this project, I use a RS360 micro water pump which is drived by relay,
  #the realy's open/close status define start/stop water. 
  #Use steering enging to rotate the waterpipe so as to extend the irrigation field.
  
  #Steering engine pin connection:
  #deep red <--> GND
  #red      <--> VCC
  #yellow   <--> signal(X1)
  
  
  #Water pump(RS360) is powered by 5V power.
  #Realy connect to GPIO(X2).
  import pyb
  from pyb import Servo
  from pyb import Pin
  servo=Servo(1) # X1
  pin_out = Pin('X2', Pin.OUT_PP)
  
  def irrigate_start():
    pin_out.high()
    
  def irrigate_stop():
    pin_out.low()
  
  def irrigate_rotate(angle):
    servo.angle(angle)
    
  
    
  