From 5f4c984a9b9ecc6c17faa00a28684830628b21af Mon Sep 17 00:00:00 2001
From: David Lechner <david@pybricks.com>
Date: Fri, 30 Apr 2021 17:29:42 -0500
Subject: [PATCH] sets/mindstorms/robot-inventor/steerbot: PEP8

---
 .../robot-inventor/steerbot/main.py           | 94 +++++++++----------
 1 file changed, 47 insertions(+), 47 deletions(-)

diff --git a/sets/mindstorms/robot-inventor/steerbot/main.py b/sets/mindstorms/robot-inventor/steerbot/main.py
index 2175e74..b2c3c96 100644
--- a/sets/mindstorms/robot-inventor/steerbot/main.py
+++ b/sets/mindstorms/robot-inventor/steerbot/main.py
@@ -3,6 +3,10 @@ from pybricks.pupdevices import Motor, ColorSensor
 from pybricks.parameters import Port, Button, Stop
 from pybricks.tools import wait
 
+# Tuning parameters
+SPEED_MAX = 1000
+SPEED_TURN = 500
+SPEED_OFFLINE = 400
 
 # Initialize the hub, motors, and sensor
 hub = InventorHub()
@@ -11,91 +15,86 @@ drive_motor = Motor(Port.B)
 sensor = ColorSensor(Port.C)
 
 
-def WaitForButton(b):
+def wait_for_button(b):
     # Wait for press
     while b not in hub.buttons.pressed():
-        wait (10)
+        wait(10)
     # and release
     while b in hub.buttons.pressed():
-        wait (10)
+        wait(10)
 
 
 # Use the color saturation value to track line
-def GetLight():
-    return (sensor.hsv().s)
+def get_light():
+    return sensor.hsv().s
 
 
-def Calibrate():
-    global aSteerLimit
-    global lMin, lMax, signEdge
+def calibrate():
+    global a_steer_limit
+    global l_min, l_max, sign_edge
 
     # Find the Right and Left hard limits
-    aRightLimit = steer_motor.run_until_stalled(400, then=Stop.BRAKE, duty_limit=100)
-    aLeftLimit = steer_motor.run_until_stalled(-400, then=Stop.BRAKE, duty_limit=100)
+    a_right_limit = steer_motor.run_until_stalled(400, then=Stop.BRAKE, duty_limit=100)
+    a_left_limit = steer_motor.run_until_stalled(-400, then=Stop.BRAKE, duty_limit=100)
 
     # Calculate the steering limit as average of two extremes then reset
     # angle to the negative limit since steering motor is now at neg. extreme
-    aSteerLimit = (aRightLimit-aLeftLimit)//2
-    steer_motor.reset_angle(-aSteerLimit)
+    a_steer_limit = (a_right_limit - a_left_limit) // 2
+    steer_motor.reset_angle(-a_steer_limit)
 
     # Scan from -30 to 30 to get min max of light sensor value
-    steer_motor.run_target(1000,-30, then=Stop.BRAKE)
-    lMin = 1024; lMax = 0
-    lLeft = GetLight()
+    steer_motor.run_target(1000, -30, then=Stop.BRAKE)
+    l_min = 1024
+    l_max = 0
+    l_left = get_light()
     steer_motor.run(100)
-    c = 0
+
     while steer_motor.angle() < 30:
-        c += 1
-        l = GetLight()
-        if l > lMax: lMax = l
-        if l < lMin: lMin = l
+        l = get_light()
+        if l > l_max:
+            l_max = l
+        if l < l_min:
+            l_min = l
         wait(5)
+
     steer_motor.stop()
-    lRight = GetLight()
-    # signEdge is positive 1 if left edge and -1 if right edge
-    signEdge = 1 if lLeft < lRight else -1
+    l_right = get_light()
+    # sign_edge is positive 1 if left edge and -1 if right edge
+    sign_edge = 1 if l_left < l_right else -1
 
     # Center the steering
-    steer_motor.run_target(1000,0,then=Stop.BRAKE,wait=False)
+    steer_motor.run_target(1000, 0, then=Stop.BRAKE, wait=False)
 
 
-SPEED_MAX = 1000
-SPEED_TURN = 500
-SPEED_OFFLINE = 400
-
-
-def TrackSpeedControl():
-    global lMin, lMax, signEdge
-    global aSteerLimit
-
-    lMid = (lMax+lMin+1)//2
-    m = 20.0/(lMax-lMid)
+def track_speed_control():
+    l_mid = (l_max + l_min + 1) // 2
+    m = 20.0 / (l_max - l_mid)
 
     # Calculate a threshold to determine steering is not near the edge
-    lOffEdgeThresh = (lMax-lMid) * 0.7
+    l_off_edge_thresh = (l_max - l_mid) * 0.7
 
     # Set max speed, acceleration, and max power for drive motor
     drive_motor.stop()  # must be stopped to set limits
-    drive_motor.control.limits(1000,2000,100)
+    drive_motor.control.limits(1000, 2000, 100)
 
-    while hub.buttons.pressed() == []:
+    while not any(hub.buttons.pressed()):
         # Get a new light value and subtract mid to get signed error from edge
-        l = signEdge * (GetLight()-lMid)
+        l = sign_edge * (get_light() - l_mid)
 
         # Create a new target for the steering motor to move toward the
         # approximate position of the edge
         a = steer_motor.angle()
-        t = a - m*l
+        t = a - m * l
 
-        # Clamp the target angle to within +- aSteerLimit
-        t = min(t, aSteerLimit)
-        t = max(t, -aSteerLimit)
+        # Clamp the target angle to within +- a_steer_limit
+        t = min(t, a_steer_limit)
+        t = max(t, -a_steer_limit)
 
         # Now update target to move toward edge of line
         steer_motor.track_target(t)
 
         # Speed control
-        if abs(l) < lOffEdgeThresh:
+        if abs(l) < l_off_edge_thresh:
             # On edge of line
             if abs(t) < 25:
                 # and going straight
@@ -112,11 +111,12 @@ def TrackSpeedControl():
     wait(200)
     steer_motor.stop()
     drive_motor.stop()
+
     while not any(hub.buttons.pressed()):
         wait(10)
 
 
 while True:
-    WaitForButton(Button.RIGHT)
-    Calibrate()
-    TrackSpeedControl()
+    wait_for_button(Button.RIGHT)
+    calibrate()
+    track_speed_control()