Fix pins, remove `_thread`

diff --git a/go-and-stop.py b/go-and-stop.py
index 8bb55d5da622c35b5e4558b236364d92374a1841..454c8b3c1549d1f831e9d7a91011b06d2cce783f 100644 (file)
--- a/go-and-stop.py
+++ b/go-and-stop.py
@@ -1,20 +1,22 @@
 # -*- coding: utf-8 -*-
 """Run the car and stop if distance to obstacle is < 40cm."""
-from _thread import start_new_thread
 from machine import Pin, PWM
 from utime import sleep_us, ticks_us
 
 TRIG = Pin(5, Pin.OUT)
 ECHO = Pin(4, Pin.IN)
-SPEED = PWM(Pin(12), freq=1000)
+SPEED = PWM(Pin(14), freq=1000)
+BACK = PWM(Pin(15), freq=1000)
 
-dist = 4
+dist = 40
 
 def get_dist():
-    """Read data from ultrasonic sensor."""
+    """Read data from ultrasonic sensor and drive car if no obstacle."""
     global dist
+    BACK.duty(0)
     nc = ticks_us()
     while True:
+        # read sensor data
         TRIG.off()
         sleep_us(2)
         TRIG.on()
@@ -27,24 +29,14 @@ def get_dist():
             pass
         t2 = ticks_us()
         dist = (t2 - t1) / 58.0
-        nc += 20000
-        sleep_us(nc - ticks_us())
-    return
-
-def set_speed():
-    """Set PWM to control car speed."""
-    nc = ticks_us()
-    while True:
-        if dist < 20:
+        # drive if obstacle-free
+        if dist > 10:
             SPEED.duty(1023)
         else:
             SPEED.duty(0)
-        nc += 200000
+        nc += 20000
         sleep_us(nc - ticks_us())
     return
 
 if __name__ == "__main__":
-    start_new_thread(get_dist, ())
-    start_new_thread(set_speed, ())
-    while True:
-        pass
+    get_dist()