From 2392e1bc666c953ded3cf7e7b684ff22cd52ff56 Mon Sep 17 00:00:00 2001
From: Laurens Valk <laurens@pybricks.com>
Date: Fri, 24 Apr 2020 13:01:06 +0200
Subject: [PATCH] official_models/ev3/educator: add line follower

---
 .../robot_educator_line/.gitignore            |  3 ++
 .../.vscode/extensions.json                   | 13 ++++++
 .../robot_educator_line/.vscode/launch.json   | 15 +++++++
 .../robot_educator_line/.vscode/settings.json |  7 +++
 .../robot_educator_line/main.py               | 45 +++++++++++++++++++
 5 files changed, 83 insertions(+)
 create mode 100644 official_models/ev3/education_core/robot_educator_line/.gitignore
 create mode 100644 official_models/ev3/education_core/robot_educator_line/.vscode/extensions.json
 create mode 100644 official_models/ev3/education_core/robot_educator_line/.vscode/launch.json
 create mode 100644 official_models/ev3/education_core/robot_educator_line/.vscode/settings.json
 create mode 100644 official_models/ev3/education_core/robot_educator_line/main.py

diff --git a/official_models/ev3/education_core/robot_educator_line/.gitignore b/official_models/ev3/education_core/robot_educator_line/.gitignore
new file mode 100644
index 0000000..00f2d38
--- /dev/null
+++ b/official_models/ev3/education_core/robot_educator_line/.gitignore
@@ -0,0 +1,3 @@
+__pycache__/
+*.pyc
+.venv/
diff --git a/official_models/ev3/education_core/robot_educator_line/.vscode/extensions.json b/official_models/ev3/education_core/robot_educator_line/.vscode/extensions.json
new file mode 100644
index 0000000..f8f1a44
--- /dev/null
+++ b/official_models/ev3/education_core/robot_educator_line/.vscode/extensions.json
@@ -0,0 +1,13 @@
+{
+	// See http://go.microsoft.com/fwlink/?LinkId=827846 to learn about workspace recommendations.
+	// Extension identifier format: ${publisher}.${name}. Example: vscode.csharp
+
+	// List of extensions which should be recommended for users of this workspace.
+	"recommendations": [
+		"lego-education.ev3-micropython"
+	],
+	// List of extensions recommended by VS Code that should not be recommended for users of this workspace.
+	"unwantedRecommendations": [
+		"ms-python.python"
+	]
+}
\ No newline at end of file
diff --git a/official_models/ev3/education_core/robot_educator_line/.vscode/launch.json b/official_models/ev3/education_core/robot_educator_line/.vscode/launch.json
new file mode 100644
index 0000000..d933aeb
--- /dev/null
+++ b/official_models/ev3/education_core/robot_educator_line/.vscode/launch.json
@@ -0,0 +1,15 @@
+{
+	// Use IntelliSense to learn about possible attributes.
+	// Hover to view descriptions of existing attributes.
+	// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+	"version": "0.2.0",
+	"configurations": [
+		{
+			"name": "Download and Run",
+			"type": "ev3devBrowser",
+			"request": "launch",
+			"program": "/home/robot/${workspaceRootFolderName}/main.py",
+			"interactiveTerminal": false
+		}
+	]
+}
diff --git a/official_models/ev3/education_core/robot_educator_line/.vscode/settings.json b/official_models/ev3/education_core/robot_educator_line/.vscode/settings.json
new file mode 100644
index 0000000..b0968c1
--- /dev/null
+++ b/official_models/ev3/education_core/robot_educator_line/.vscode/settings.json
@@ -0,0 +1,7 @@
+// Place your settings in this file to overwrite default and user settings.
+{
+	"files.eol": "\n",
+	"debug.openDebug": "neverOpen",
+	"python.linting.enabled": false,
+	"python.languageServer": "None"
+}
diff --git a/official_models/ev3/education_core/robot_educator_line/main.py b/official_models/ev3/education_core/robot_educator_line/main.py
new file mode 100644
index 0000000..394ea27
--- /dev/null
+++ b/official_models/ev3/education_core/robot_educator_line/main.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env pybricks-micropython
+from pybricks.ev3devices import Motor, ColorSensor
+from pybricks.parameters import Port
+from pybricks.tools import wait
+from pybricks.robotics import DriveBase
+
+# Initialize the motors.
+left_motor = Motor(Port.B)
+right_motor = Motor(Port.C)
+
+# Initialize the color sensor.
+line_sensor = ColorSensor(Port.S3)
+
+# Initialize the drive base.
+robot = DriveBase(left_motor, right_motor, wheel_diameter=55.5, axle_track=104)
+
+# Calculate the light threshold. Choose values based on your measurements.
+BLACK = 9
+WHITE = 85
+threshold = (BLACK + WHITE) / 2
+
+# Set the drive speed at 100 millimeters per second.
+DRIVE_SPEED = 100
+
+# Set the gain of the proportional line controller. This means that for every
+# percentage point of light deviating from the threshold, we set the turn
+# rate of the drivebase to 1.2 degrees per second.
+
+# For example, if the light value deviates from the threshold by 10, the robot
+# steers at 10*1.2 = 12 degrees per second.
+PROPORTIONAL_GAIN = 1.2
+
+# Start following the line endlessly.
+while True:
+    # Calculate the deviation from the threshold.
+    deviation = line_sensor.reflection() - threshold
+
+    # Calculate the turn rate.
+    turn_rate = PROPORTIONAL_GAIN * deviation
+
+    # Set the drive base speed and turn rate.
+    robot.drive(DRIVE_SPEED, turn_rate)
+
+    # You can wait for a short time or do other things in this loop.
+    wait(10)