examples: Add 'LED Hunt' example (#794)

Co-authored-by: Piero Cornice <[email protected]>

examples/led_hunt.py

@@ -0,0 +1,108 @@
+"""
+LED Hunt
+
+Author: Piero Cornice
+
+- Capture the faint LED with the bright one by tilting the device.
+- Do it 10 times to win the game.
+- See how quick you've been, to compete with friends.
+- Press either A or B to reset the game.
+"""
+
+from microbit import *
+from random import randint
+import music
+import time
+
+
+def normalize(value, input_range, output_range) -> float:
+    '''
+    Rescale x from its min/max range to a target range [a, b] using the formula:
+
+        a + (x - min(x)) * (b - a) / (max(x) - min(x))
+    '''
+    return output_range[0] + ((value - input_range[0]) * (output_range[1] - output_range[0])) / (input_range[0] - input_range[1])
+
+def animate(images, delay_ms=50):
+    for img in images:
+        display.show(Image(img))
+        sleep(delay_ms)
+    display.clear()
+
+
+def initialize_game():
+    global score, x_target, y_target, start_at
+    music.play(music.JUMP_UP, wait=False)
+    animate(animation_start)
+    score = 0
+    x_target, y_target = set_target()
+    start_at = time.ticks_ms()
+
+
+def set_target():
+    x_target, y_target = 2, 2
+    # make sure the target is not in the center, as we'll probably start from there
+    while x_target == 2 and y_target == 2:
+        x_target = randint(0, 4)
+        y_target = randint(0, 4)
+    return x_target, y_target
+
+
+animation_win = [
+    '00000:00600:06960:00600:00000',
+    '00600:06960:69696:06960:00600',
+    '06960:69696:96069:69696:06960',
+    '69696:96069:60006:96069:69696',
+    '96069:60006:00000:60006:96069',
+    '60006:00000:00000:00000:60006']
+
+animation_start = list(reversed(animation_win))
+
+# Initialize game variables with dummy values
+# and let initialize_game() do the rest.
+score, x_target, y_target, start_at = 0, 0, 0, 0
+initialize_game()
+
+while True:
+    if button_a.was_pressed() or button_b.was_pressed():
+        initialize_game()
+
+    x_acc, y_acc, _ = accelerometer.get_values()
+
+    x_acc = min(max(x_acc, -500), 500)
+    y_acc = min(max(y_acc, -500), 500)
+
+    x_pos = int(abs(normalize(x_acc, [-500, 500], [0, 4])))
+    y_pos = int(abs(normalize(y_acc, [-500, 500], [0, 4])))
+
+    #print('X: ', x_acc, ' => ', x_pos)
+    #print('Y: ', y_acc, ' => ', y_pos)
+
+    if x_pos == x_target and y_pos == y_target:
+        # Win! Set a new target
+        music.play(music.BA_DING, wait=False)
+        score += 1
+        display.show(score)
+        sleep(1000)
+
+        if score <= 9:
+            # End of match: set a new target
+            animate(animation_win)
+            x_target, y_target = set_target()
+        else:
+            # End of game
+            # Show the elapsed time and restart the game
+            end_at = time.ticks_ms()
+            music.play(music.POWER_UP, wait=False)
+            for _ in range(3):
+                animate(animation_win)
+            elapsed_time = time.ticks_diff(end_at, start_at) // 1000
+            display.scroll(str(elapsed_time) + ' sec', delay=100)
+            initialize_game()
+
+    # Update the screen
+    display.clear()
+    display.set_pixel(x_target, y_target, 5)
+    display.set_pixel(x_pos, y_pos, 9)
+    sleep(100)
+