Add Stumble Bot code for Circuit Playground Express

Initial implementation of Stumble Bot using CircuitPython with servos and button control.

Author: TheKitty

Crickits/Crickit_Stumblebot/code.py

@@ -0,0 +1,89 @@
+# SPDX-FileCopyrightText: 2018 Dano Wall for Adafruit Industries
+# SPDX-FileCopyrightText: 2018 Anne Barela for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+
+# Stumble Bot, coded in CircuitPython
+# Using an Adafruit Circuit Playground Express, Crickit, and 2 servos
+# Dano Wall, Anne Barela for Adafruit Industries, MIT License, May, 2018
+#
+import time
+from digitalio import DigitalInOut, Direction, Pull
+from adafruit_seesaw.seesaw import Seesaw
+from adafruit_seesaw.pwmout import PWMOut
+
+from adafruit_motor import servo
+from busio import I2C
+import board
+
+# Create seesaw object for Circuit Playground Express to talk to Crickit
+i2c = I2C(board.SCL, board.SDA)
+seesaw = Seesaw(i2c)
+
+led = DigitalInOut(board.D13)            # Set up Red LED
+led.direction = Direction.OUTPUT
+
+button_A = DigitalInOut(board.BUTTON_A)  # Set up switch A
+button_A.direction = Direction.INPUT
+button_A.pull = Pull.DOWN
+
+# Create servos list
+servos = []
+for ss_pin in (17, 16):  # Only use 2 servos, append , 15, 14 if using 4
+    pwm = PWMOut(seesaw, ss_pin)
+    pwm.frequency = 50
+    _servo = servo.Servo(pwm, min_pulse=600, max_pulse=2500)
+    _servo.angle = 90   # starting angle, middle
+    servos.append(_servo)
+
+def servo_front(direction):
+    if direction > 0:
+        index = 50
+        while index <= 90:
+            servos[1].angle = index
+            time.sleep(0.040)
+            index = index + 1
+    if direction < 0:
+        index = 90
+        while index >= 50:
+            servos[1].angle = index
+            time.sleep(0.040)
+            index = index - 1
+    time.sleep(0.002)
+
+def servo_back(direction):
+    if direction > 0:
+        index = 65
+        while index <= 95:
+            servos[0].angle = index
+            time.sleep(0.040)
+            index = index + 3
+    if direction < 0:
+        index = 95
+        while index >= 65:
+            servos[0].angle = index
+            time.sleep(0.040)
+            index = index - 3
+    time.sleep(0.020)
+
+print("Its Stumble Bot Time")
+
+while True:
+    if button_A.value:  # If button A is pressed, start bot
+        led.value = True  # Turn on LED 13 to show we're gone!
+        for i in range(5):
+            print("back 1")
+            servo_back(1)
+            time.sleep(0.100)
+            print("front 1")
+            servo_front(1)
+            time.sleep(0.100)
+            print("back 2")
+            servo_back(-1)
+            time.sleep(0.100)
+            print("front 2")
+            servo_front(-1)
+            time.sleep(0.100)
+        led.value = False
+    # end if
+# end while