Flapping Halloween Vampire Bat

Fully Reversible Pink/Purple USB A to micro B Cable - 1m long

This cable is not only super-fashionable, with a woven pink and purple Blinka-like pattern, it's also fully reversible! That's right, you will save seconds a day by...

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3x AA Battery Holder with On/Off Switch and 2-Pin JST

Angled shot of 3 x AA battery holder with on-off switch and JST SH connector.

Here's another addition to our growing family of AA battery holders. Behold! A holder for three (3) AA batteries!...

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Alkaline AA batteries (LR6) - 3 pack

Battery power for your portable project! These batteries are good quality at a good price, and work fantastic with any of the kits or projects in the shop that use AAs. This is a pack...

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Circuit Playground Bluefruit - Bluetooth Low Energy

This project also works with a Circuit Playground Bluefruit if the Circuit Playground Express is not available.

shot of a Black woman's neon-green manicured hand holding up a Circuit Playground Bluefruit glowing rainbow LEDs.

Circuit Playground Bluefruit is our third board in the Circuit Playground series, another step towards a perfect introduction to electronics and programming. We've...

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Right Wing Servo

Servo GND to board GND (black wire)
Servo VIN to board 3.3V (red wire)
Servo Data to board A6 (white wire)

Left Wing Servo

Servo GND to board GND (black wire)
Servo VIN to board 3.3V (red wire)
Servo Data to board A3 (white wire)

The Halloween bat may be assembled with 3D printed parts, described below. The pieces could also be cut from other materials, such as wood, acrylic or even cardboard.

The STL files can be downloaded directly here or from Thingiverse.

bat_STLfiles.zip

Thingiverse download

The Circuit Playground and servo motors mount to the body of the bat. The NeoPixels are visible in the cutout for the board.

Each wing mounts to a servo with M2 screws.

You can paint the bat's fangs and eyes to make them standout. Googly Eyes work too.

As we continue to develop CircuitPython and create new releases, we will stop supporting older releases. If you are running an older version of CircuitPython, you need to update. Click the button below to download the latest!

Install or update CircuitPython!

Follow this quick step-by-step for super-fast Python power :)

Download the latest version of CircuitPython for this board via CircuitPython.org

Click the link above and download the latest UF2 file

Download and save it to your Desktop (or wherever is handy)

Plug your Circuit Playground Express into your computer using a known-good USB cable

A lot of people end up using charge-only USB cables and it is very frustrating! So make sure you have a USB cable you know is good for data sync

Double-click the small Reset button in the middle of the CPX, you will see all of the LEDs turn green. If they turn all red, check the USB cable, try another USB port, etc.

(If double-clicking doesn't do it, try a single-click!)

You will see a new disk drive appear called CPLAYBOOT

Drag the adafruit-circuitpython-etc...uf2 file onto it

The CPLAYBOOT drive will disappear and a new disk drive will appear called CIRCUITPY

That's it! You're done :)

Further Information

For more detailed info on installing CircuitPython, check out Installing CircuitPython.

Once you've finished setting up your Circuit Playground Express with CircuitPython, you can access the code and necessary libraries by downloading the Project Bundle.

To do this, click on the Download Project Bundle button in the window below. It will download as a zipped folder.

Download Project Bundle

# SPDX-FileCopyrightText: 2022 Liz Clark for Adafruit Industries
#
# SPDX-License-Identifier: MIT

import time
import board
import pwmio
import neopixel
from adafruit_motor import servo
from adafruit_led_animation.animation.comet import Comet
from adafruit_led_animation.sequence import AnimationSequence
from adafruit_led_animation.color import PURPLE

#  create 2 PWM instances for the servos
left_pwm = pwmio.PWMOut(board.A3, duty_cycle=2 ** 15, frequency=50)
right_pwm = pwmio.PWMOut(board.A6, duty_cycle=2 ** 15, frequency=50)

#  left wing servo
left_servo = servo.Servo(left_pwm)
#  right wing servo
right_servo = servo.Servo(right_pwm)

#  use onboard neopixels on CPX
pixel_pin = board.NEOPIXEL
#  number of onboard neopixels
num_pixels = 10

#  neopixels object
pixels = neopixel.NeoPixel(pixel_pin, num_pixels, brightness=0.05, auto_write=False)

#  comet animation
comet = Comet(pixels, speed=0.01, color=PURPLE, tail_length=10, bounce=True)

#  create animation sequence
animations = AnimationSequence(comet)

#  beginning angles for each wing
left_angle = 100
right_angle = 30
#  minimum range for the servos
min_range = 30
#  maximum range for the servos
max_range = 100
#  the change in degrees for the servos
degree_change = 10
#  it's not recommended to go faster than 0.05
speed = 0.05

while True:
	#  run comet animation while servos move
    animations.animate()

	#  left angle decreases by 10
    left_angle = left_angle - degree_change
	#  once it's less than 30 degrees, reset to 100
    if left_angle < min_range:
        left_angle = max_range
	#  right angle increases by 10
    right_angle = right_angle + degree_change
	#  once it's greater than 100, reset to 30
    if right_angle > max_range:
        right_angle = min_range
	#  move left wing
    left_servo.angle = left_angle
	#  move right wing
    right_servo.angle = right_angle
	#  delay
    time.sleep(0.05)

# SPDX-FileCopyrightText: 2022 Liz Clark for Adafruit Industries
#
# SPDX-License-Identifier: MIT

import time
import board
import pwmio
import neopixel
from adafruit_motor import servo
from adafruit_led_animation.animation.comet import Comet
from adafruit_led_animation.sequence import AnimationSequence
from adafruit_led_animation.color import PURPLE

#  create 2 PWM instances for the servos
left_pwm = pwmio.PWMOut(board.A3, duty_cycle=2 ** 15, frequency=50)
right_pwm = pwmio.PWMOut(board.A6, duty_cycle=2 ** 15, frequency=50)

#  left wing servo
left_servo = servo.Servo(left_pwm)
#  right wing servo
right_servo = servo.Servo(right_pwm)

#  use onboard neopixels on CPX
pixel_pin = board.NEOPIXEL
#  number of onboard neopixels
num_pixels = 10

#  neopixels object
pixels = neopixel.NeoPixel(pixel_pin, num_pixels, brightness=0.05, auto_write=False)

#  comet animation
comet = Comet(pixels, speed=0.01, color=PURPLE, tail_length=10, bounce=True)

#  create animation sequence
animations = AnimationSequence(comet)

#  beginning angles for each wing
left_angle = 100
right_angle = 30
#  minimum range for the servos
min_range = 30
#  maximum range for the servos
max_range = 100
#  the change in degrees for the servos
degree_change = 10
#  it's not recommended to go faster than 0.05
speed = 0.05

while True:
	#  run comet animation while servos move
    animations.animate()

	#  left angle decreases by 10
    left_angle = left_angle - degree_change
	#  once it's less than 30 degrees, reset to 100
    if left_angle < min_range:
        left_angle = max_range
	#  right angle increases by 10
    right_angle = right_angle + degree_change
	#  once it's greater than 100, reset to 30
    if right_angle > max_range:
        right_angle = min_range
	#  move left wing
    left_servo.angle = left_angle
	#  move right wing
    right_servo.angle = right_angle
	#  delay
    time.sleep(0.05)

Upload the Code and Libraries to the Circuit Playground Express

After downloading the Project Bundle, plug your Circuit Playground Express into the computer's USB port with a known good USB data+power cable. You should see a new flash drive appear in the computer's File Explorer or Finder (depending on your operating system) called CIRCUITPY. Unzip the folder and copy the following items to the Circuit Playground Express' CIRCUITPY drive.

lib folder
code.py

Your Circuit Playground Express CIRCUITPY drive should look like this after copying the lib folder and the code.py file.

How the CircuitPython Code Works

The code begins by setting up two pins for the servo motors to have PWM out. Then left_servo and right_servo are created as servo objects.

#  create 2 PWM instances for the servos
left_pwm = pwmio.PWMOut(board.A3, duty_cycle=2 ** 15, frequency=50)
right_pwm = pwmio.PWMOut(board.A6, duty_cycle=2 ** 15, frequency=50)

#  left wing servo
left_servo = servo.Servo(left_pwm)
#  right wing servo
right_servo = servo.Servo(right_pwm)

#  create 2 PWM instances for the servos
left_pwm = pwmio.PWMOut(board.A3, duty_cycle=2 ** 15, frequency=50)
right_pwm = pwmio.PWMOut(board.A6, duty_cycle=2 ** 15, frequency=50)

#  left wing servo
left_servo = servo.Servo(left_pwm)
#  right wing servo
right_servo = servo.Servo(right_pwm)

The onboard NeoPixels are used for this project. The pin to access them is board.NEOPIXEL. Then, pixels is setup as the NeoPixel object.

#  use onboard neopixels on CPX
pixel_pin = board.NEOPIXEL
#  number of onboard neopixels
num_pixels = 10

#  neopixels object
pixels = neopixel.NeoPixel(pixel_pin, num_pixels, brightness=0.05, auto_write=False)

#  use onboard neopixels on CPX
pixel_pin = board.NEOPIXEL
#  number of onboard neopixels
num_pixels = 10

#  neopixels object
pixels = neopixel.NeoPixel(pixel_pin, num_pixels, brightness=0.05, auto_write=False)

The Comet animation is setup and added to the AnimationSequence(). If you want to change the color for the animation, you would change the color property.

#  comet animation
comet = Comet(pixels, speed=0.01, color=PURPLE, tail_length=10, bounce=True)

#  create animation sequence
animations = AnimationSequence(comet)

#  comet animation
comet = Comet(pixels, speed=0.01, color=PURPLE, tail_length=10, bounce=True)

#  create animation sequence
animations = AnimationSequence(comet)

There are a few variables for the servo motor angles that are defined before the loop. You can change these values to customize the look of your bat's wing flapping.

min_range and max_range define the angle range of the wings. Change these values if you want to increase or decrease the range of the motor angles between 0 and 180. degree_change is the rate of movement for the motors. If you increase this value, the motors will move more abruptly; decrease the value and the motors will move more incrementally. speed is the delay amount in the loop and as a result, determines how fast the servo motors move.

#  beginning angles for each wing
left_angle = 100
right_angle = 30
#  minimum range for the servos
min_range = 30
#  maximum range for the servos
max_range = 100
#  the change in degrees for the servos
degree_change = 10
#  it's not recommended to go faster than 0.05
speed = 0.05

#  beginning angles for each wing
left_angle = 100
right_angle = 30
#  minimum range for the servos
min_range = 30
#  maximum range for the servos
max_range = 100
#  the change in degrees for the servos
degree_change = 10
#  it's not recommended to go faster than 0.05
speed = 0.05

In the loop, animations.animate() allows the comet NeoPixel animation to run as long as the code is running.

#  run comet animation while servos move
    animations.animate()

#  run comet animation while servos move
    animations.animate()

The servos move like mirror images of each other to imitate a wing flapping motion. As a result, the angle of the servo on the left increases while the angle of the servo on the right decreases.

The left_angle value decreases by the value of degree_change. Once its value is less than min_range, its reset to max_range.

#  left angle decreases by 10
    left_angle = left_angle - degree_change
	#  once it's less than 30 degrees, reset to 100
    if left_angle < min_range:
        left_angle = max_range

#  left angle decreases by 10
    left_angle = left_angle - degree_change
	#  once it's less than 30 degrees, reset to 100
    if left_angle < min_range:
        left_angle = max_range

The right_angle value increases by the value of degree_change. Once its value is greater than max_range, its reset to min_range.

#  right angle increases by 10
    right_angle = right_angle + degree_change
	#  once it's greater than 100, reset to 30
    if right_angle > max_range:
        right_angle = min_range

#  right angle increases by 10
    right_angle = right_angle + degree_change
	#  once it's greater than 100, reset to 30
    if right_angle > max_range:
        right_angle = min_range

The servos move by changing the value of their angle property.