Added a speed reading example for inventor

micropython/examples/inventor2040w/motors/read_speeds.py

@@ -0,0 +1,46 @@
+import time
+from inventor import Inventor2040W, NUM_MOTORS  # , MOTOR_A, MOTOR_B
+# from pimoroni import REVERSED_DIR
+
+"""
+Demonstrates how to read the speeds of Inventor 2040 W's two encoders.
+
+Press "User" to exit the program.
+"""
+
+# Wheel friendly names
+NAMES = ["LEFT", "RIGHT"]
+
+# Constants
+GEAR_RATIO = 50                         # The gear ratio of the motor
+SPEED = 1.0                             # The speed to drive the motors at
+SLEEP = 0.1                             # The time to sleep between each capture
+
+# Create a new Inventor2040W
+board = Inventor2040W(motor_gear_ratio=GEAR_RATIO)
+
+# Uncomment the below lines (and the top imports) to
+# reverse the counting direction of an encoder
+# encoders[MOTOR_A].direction(REVERSED_DIR)
+# encoders[MOTOR_B].direction(REVERSED_DIR)
+
+# Set both motors driving
+for motor in board.motors:
+    motor.speed(SPEED)
+
+# Variables for storing encoder captures
+captures = [None] * NUM_MOTORS
+
+# Read the encoders until the user button is pressed
+while not board.switch_pressed():
+
+    # Capture the state of all the encoders since the last capture, SLEEP seconds ago
+    for i in range(NUM_MOTORS):
+        captures[i] = board.encoders[i].capture()
+
+    # Print out the speeds from each encoder
+    for i in range(NUM_MOTORS):
+        print(NAMES[i], "=", captures[i].revolutions_per_second, end=", ")
+    print()
+
+    time.sleep(SLEEP)