Python code

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import math
import time

from adafruit_circuitplayground import cp

# NeoPixel #9 is set to red to indicate no (good) reading.
cp.pixels[9] = (255, 0, 0)

# Loop forever
while True:
    # If button A or B is pressed
    if cp.button_a or cp.button_b:
        # Initialise a_x, a_y, and a_z.
        a_x = 0
        a_y = 0
        a_z = 0

        # Take 10 measurements for a_x, a_y, and a_z.
        for count in range(10):
            x, y, z = cp.acceleration
            a_x = a_x + x
            a_y = a_y + y
            a_z = a_z + z
            time.sleep(0.01)

        # Calculate the average of the 10 measurements.
        a_x = a_x / 10
        a_y = a_y / 10
        a_z = a_z / 10

        # Assume the reading is good.
        reading = True

        # Check for levelness:
        # Ideally, a_z = 0 if the Circuit Playground is hold vertically.
        # However, a small amount of acceleration is permitted.
        if abs(a_z) > 1:
            reading = False

        # Compute acceleration using norm.
        acceleration = math.sqrt(a_x*a_x + a_y*a_y + a_z*a_z)

        # Check for motion:
        # Ideally, accelaration = 9.81 (gravity = 9.81 m/s^2).
        # However, a small amount of acceleration is permitted.
        if acceleration > 10:
            reading = False

        # NeoPixel #9 is set to indicate the quality of the reading.
        if reading:
            cp.pixels[9] = (0, 255, 0) # Green light for good reading.
        else:
            cp.pixels[9] = (255, 0, 0) # Red light for try again.
            continue

        # Compute tan(𝛼).
        # Use |a_x| to avoid trouble when flipping the board.
        tan_alpha = abs(a_x) / a_y

        # Compute 𝛼 (atan returns radians), convert it to degrees,
        # then take the absolute value, and finally convert it to an 
        # integer.
        alpha = int(abs(math.degrees(math.atan(tan_alpha))))

        # NeoPixel #8 is set to indicate the sign of the angle.
        if tan_alpha < 0:
            cp.pixels[8] = (0, 0, 255) # Blue light for negative.
        else:
            cp.pixels[8] = (255, 255, 255) # White light for positive.

        # Display angle magnitude on NeoPixels #0 to #7 as 8-bit value.
        for p in range(8):
            # Check if right bit (0x1 = 00000001) is set.
            if alpha & 0x1 == 1:
                cp.pixels[p] = (255, 255, 255) # Turn on the NeoPixel
            else:
                cp.pixels[p] = (0, 0, 0) # Turn off the NeoPixel
            # Shift 𝛼 right by 1 bit.
            # Dropping the right bit equals dividing the number by 2.
            alpha = alpha >> 1

        # Depending on the switch, write to
        # * the serial console (if True, i.e. left), or to
        # * the CircuitPython storage (if False, i.e. right).
        if cp.switch:
            # Read d and e as float.
            d = float(input("What is the distance to the object in meters? "))
            e = float(input("What is the eye level in meters? "))
            # Substract e if tan_alpha is negative.
            e = math.copysign(e, tan_alpha)
            # Print the height of the object.
            print("The height of the object is", "{:.2f}".format(d * tan_alpha + e), "meters.\n")
        else:
            f = open("tan_alpha.csv", "a")
            f.write(repr(tan_alpha) + "\n")
            f.close()

import storage

from adafruit_circuitplayground import cp

storage.remount("/", readonly=cp.switch)