tests/pup/motors: Read logged data in script.

Author: laurensvalk

tests/pup/motors/log_servo.py

@@ -27,10 +27,29 @@
 motor.run_target(500, 360)
 
 # Wait so we can also log hold capability, then turn off the motor completely.
-wait(1000)
+wait(100)
 motor.stop()
 
 # Save the data by printing it. Pybricksdev will capture the printed
 # data and save it to the given path relative to this script.
-motor.log.save('build/servo_data.txt')
-motor.control.log.save('build/control_data.txt')
+motor.log.save("build/servo_data.txt")
+motor.control.log.save("build/control_data.txt")
+
+# The log can also be read from the user script. For fun, let's print the
+# position and the estimated speed in a rotated plot. We show only 1 in 3
+# samples here and scale the speed and angle values for better visibility.
+for i in range(len(motor.log) / 3):
+
+    # Read the (i * 3)th row in the data log.
+    values = motor.log.get(i * 3)
+    speed = values[7]
+    angle = values[2]
+
+    # Turn it into a line of spaces with * for speed and + for angle.
+    line = [ord(" ")] * 100
+    line[speed // 6] = ord("*")
+    line[angle // 5] = ord("+")
+
+    # Print it. Looked at it sideways, you should see a trapezoidal graph
+    # for speed and a gradual ramp for the angle.
+    print(bytes(line))