Python Forum

Hello - I have written the code below which works well with my hardware. I want to use the 'distance' variable that I have set in 'def Ultra', outside of the 'def Ultra' routine. Right now, the code indicates when my robot is too near to an object - I want to use this indication to expand my program, putting my motors into slow and super slow speeds.

Any help will be greatly appreciated

from machine import Pin
import utime

# Set up Ultrasonic Trigger and Echo
trigger = Pin(3, Pin.OUT)
echo = Pin(2, Pin.IN)

# Set up the LED pins
red = Pin(20, Pin.OUT)
amber = Pin(19, Pin.OUT)
green = Pin(18, Pin.OUT)

def ultra():
   trigger.low()
   utime.sleep_us(2)
   trigger.high()
   utime.sleep_us(5)
   trigger.low()
   while echo.value() == 0:
       signaloff = utime.ticks_us()
   while echo.value() == 1:
       signalon = utime.ticks_us()
   timepassed = signalon - signaloff
   distance = (timepassed * 0.0343) / 2
   if distance <= 10: # If reading is less than or equal to 20
         
        red.value(1) # Red ON
        amber.value(0)
        green.value(0)
   elif 10 < distance < 20: # If reading is between 20 and 40
    
        red.value(0) 
        amber.value(1) # Amber ON
        green.value(0)
   elif distance >= 20: # If reading is greater than or equal to 40
            
        red.value(0) 
        amber.value(0)
        green.value(1) # Green ON
        
   print("The distance from object is ",distance,"cm")
   
while True:
   ultra()
   utime.sleep(1)

At the end of the ultra() function add:

return distance

When calling the function:

distance = ultra()

This will make the distance available as a global variable in the module.