# Flapping Halloween Vampire Bat
## Overview
If Halloween has snuck up on you, have no fear! This project gets you from zero to flapping vampire bat with no soldering required. You'll use a Circuit Playground Express, two servo motors and CircuitPython to build this fun Halloween prop.
https://youtube.com/shorts/Qoh61HzeLwE
The bat's wings are mounted to two servo motors that move up and down to create a flapping effect. The servo motors have alligator clips that attach to the pads on the Circuit Playground Express.
The NeoPixels on the Circuit Playground Express animate with a swirly comet pattern.
## Prerequisite Guides
[Adafruit Circuit Playground Express](https://learn.adafruit.com/adafruit-circuit-playground-express)
[CircuitPython LED Animations](https://learn.adafruit.com/circuitpython-led-animations)
[Using Servos With CircuitPython and Arduino](https://learn.adafruit.com/using-servos-with-circuitpython)
## Parts
### Circuit Playground Express
[Circuit Playground Express](https://www.adafruit.com/product/3333)
**Circuit Playground Express** is the next step towards a perfect introduction to electronics and programming. We've taken the original Circuit Playground Classic and made it even better! Not only did we pack even more sensors in, we also made it even easier to...
In Stock
[Buy Now](https://www.adafruit.com/product/3333)
[Related Guides to the Product](https://learn.adafruit.com/products/3333/guides)
### Micro Servo with Alligator Clips
[Micro Servo with Alligator Clips](https://www.adafruit.com/product/5592)
This servo is [just like our classic Micro Servo](https://www.adafruit.com/product/169) but has 3 alligator clip test leads at the end! This makes it perfect for plug-and-play support with any of our boards with alligator-clip-friendly input/output pins, like the
In Stock
[Buy Now](https://www.adafruit.com/product/5592)
[Related Guides to the Product](https://learn.adafruit.com/products/5592/guides)
### Circuit Playground Bolt-On Kit
[Circuit Playground Bolt-On Kit](https://www.adafruit.com/product/3816)
You have a [Circuit Playground Express](https://www.adafruit.com/product/3333), but you need to mount it to your charming cardboard robot friend, eh? Not so easy if you don't have a set of standoffs!
In this kit comes:
- 6 x M3 12mm brass hexagonal...
In Stock
[Buy Now](https://www.adafruit.com/product/3816)
[Related Guides to the Product](https://learn.adafruit.com/products/3816/guides)
### Fully Reversible Pink/Purple USB A to micro B Cable - 1m long
[Fully Reversible Pink/Purple USB A to micro B Cable - 1m long](https://www.adafruit.com/product/4111)
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 not having to flip the cable around.
First let's talk about the cover and over-molding. We got these...
In Stock
[Buy Now](https://www.adafruit.com/product/4111)
[Related Guides to the Product](https://learn.adafruit.com/products/4111/guides)
### 3x AA Battery Holder with On/Off Switch and 2-Pin JST
[3x AA Battery Holder with On/Off Switch and 2-Pin JST](https://www.adafruit.com/product/4779)
Here's another addition to our growing family of [AA battery holders](https://www.adafruit.com/category/563). Behold! A holder for three (3) AA batteries! It's got a 6" long genuine JST-PH 2-pin cable connector, an On/Off switch, and, oh yes, it's in...
In Stock
[Buy Now](https://www.adafruit.com/product/4779)
[Related Guides to the Product](https://learn.adafruit.com/products/4779/guides)
### Alkaline AA batteries (LR6) - 3 pack
[Alkaline AA batteries (LR6) - 3 pack](https://www.adafruit.com/product/3521)
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 of **3 AA batteries**.
These batteries are Alkaline (MnO2) chemistry, with a voltage...
In Stock
[Buy Now](https://www.adafruit.com/product/3521)
[Related Guides to the Product](https://learn.adafruit.com/products/3521/guides)
Info:
### Circuit Playground Bluefruit - Bluetooth® Low Energy
[Circuit Playground Bluefruit - Bluetooth® Low Energy](https://www.adafruit.com/product/4333)
**Circuit Playground Bluefruit** is our third board in the Circuit Playground series, another step towards a perfect introduction to electronics and programming. We've taken the popular Circuit Playground Express and made it even better! Now the main chip is an nRF52840...
Out of Stock
[Buy Now](https://www.adafruit.com/product/4333)
[Related Guides to the Product](https://learn.adafruit.com/products/4333/guides)
# Flapping Halloween Vampire Bat
## Circuit Diagram
**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)
# Flapping Halloween Vampire Bat
## 3D Printing
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](https://cdn-learn.adafruit.com/assets/assets/000/116/155/original/bat_STLfiles.zip?1666622809)
[Thingiverse download](https://www.thingiverse.com/thing:5584393)
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.
# Flapping Halloween Vampire Bat
## CircuitPython
Danger:
# 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](https://circuitpython.org/board/circuitplayground_express/)
**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](../../../../welcome-to-circuitpython/installing-circuitpython).
# Flapping Halloween Vampire Bat
## Code the Halloween Bat
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.
https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/main/CPX_Halloween_Bat/code.py
## 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.
```python
# 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.
```python
# 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.
```python
# 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.
```python
# 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.
```python
# 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`.
```python
# 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`.
```auto
# 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.
```python
# move left wing
left_servo.angle = left_angle
# move right wing
right_servo.angle = right_angle
# delay
time.sleep(speed)
```
# Flapping Halloween Vampire Bat
## MakeCode Version
Another option for your flapping vampire bat is to code it with MakeCode. You can drag and drop the .UF2 code file onto your Circuit Playground Express to quickly prepare your bat to take flight.
**Microsoft MakeCode for Adafruit** is a web-based code editor that provides a block editor, similar to Scratch or Code.org, and also a JavaScript editor for more advanced users.
If you've never used the Circuit Playground Express with MakeCode before, [this guide is a good place to start](https://makecode.adafruit.com/courses/maker/general/coding).
[MakeCode for Circuit Playground Express Learn Guide](https://learn.adafruit.com/makecode)
## Wiring
For this version, the **left wing servo data cable** is attached to **pin** **A1** and the **right wing servo data cable** is attached to **pin A2**.
## The Code
To download the code, click the download link at the bottom of the window. To edit the code in MakeCode, click the box with arrow icon in the upper right corner of the window.
https://makecode.com/_C4y2yg9cEark
You can also download the compiled .UF2 file directly below.
[circuitplayground-cpxHalloweenBat.uf2](https://cdn-learn.adafruit.com/assets/assets/000/116/191/original/circuitplayground-cpxHalloweenBat.uf2?1666791879)
## How to Upload Code
To upload code to Circuit Playground Express, follow these instructions:
1) Connect your Circuit Playground Express to your computer using a known, good data+power micro USB cable and press the small reset button in the center of the board. All the LEDs will flash **red ** briefly **, then turn green. ** Your computer should now show a removable drive called **CPLAYBOOT. **
2) Click the **Download** button in the code window below to download the ** .UF2 file** to your computer.
3) Now ** drag and drop the .UF2 file onto the CPLAYBOOT** **drive** in your computer's file explorer or finder.
Once the file is dragged onto **CPLAYBOOT,** the drive will automatically eject itself (your computer may give you a "failed to eject drive correctly" error, you can ignore this). The code is now on your Circuit Playground Express and ready to run!
Note: If you get a drive named **CIRCUITPY** , no worries! Press the reset button **twice** to get a flash drive named **CPLAYBOOT**. The project will not run if copied onto the **CIRCUITPY** drive as it is for CircuitPython.
## How the Code Works
When the code begins, a few variables are defined:
- `right_angle` - the angle of the servo for the right wing
- `left_angle` - the angle of the servo for the left wing
- `min_range` - the minimum angle for the servos
- `max_range` - the maximum angle for the servos
- `speed` - the length of the delay
- `degree_change` - the amount of movement for the servos
In the loop, the NeoPixels display a rainbow animation while the code is running. Then, the `left_angle` and `right_angle` values are changed by the `degree_change`. If either value leaves the range defined by `min_range` and `max_range`, then the values are reset. The servo pins set the servo angles to the `left_angle` for the left wing and `right_angle` for the right wing.
# Flapping Halloween Vampire Bat
## Assembly
## Wiring
Take the servo that will be mounted as the right wing and attach its alligator clips to the Circuit Playground Express.
- **Servo** **ground (black wire)** to **board** **GND**
- **Servo power (red wire)** to **board 3.3V**
- **Servo data (white wire)** to **board A6/RX**
Take the servo that will be mounted as the left wing and attach its alligator clips to the Circuit Playground Express.
- **Servo** **ground (black wire)** to **board** **GND**
- **Servo power (red wire)** to **board 3.3V**
- **Servo data (white wire)** to **board A3**
## Mount the Circuit Playground Express
Mount the Circuit Playground Express with the M3 standoffs from the bolt-on kit to the bat body. Utilize the following pads for mounting:
- **A2**
- **A1**
- **A0**
- **A7**
- **A5**
- **A4**
## Mount the Servo Motors
Mount the servos to the bat body using M2 screws. Make sure they are oriented with the circular motor gear at the top.
## Attach the Wings
Attach each bat wing to their respective servo gear with an M2 screw.
## Alternative Mounting
If you have trouble getting the M2 screw for the wings to be tight enough, you can glue one of the servo horns to the wing and mount them that way.
# Flapping Halloween Vampire Bat
## Usage
Plug the Circuit Playground Express into a USB power supply or a battery pack with the JST battery port. The bat will power up and you'll see its wings start flapping, along with the NeoPixel comet animation.
There are a few parameters in the code that you can customize for different effects.
You can adjust the angle range (`min_range` and `max_range`) of the wings and the number of degrees that the wings move each time (`degree_change`) for different flapping effects.
You can change the color of the animation for the NeoPixels. You can also change the animation that shows on the NeoPixels. Check out the [CircuitPython LED Animations guide](https://learn.adafruit.com/circuitpython-led-animations) to see the other options available in the library.
[CircuitPython LED Animations Learn Guide](https://learn.adafruit.com/circuitpython-led-animations)
## Featured Products
### Circuit Playground Express
[Circuit Playground Express](https://www.adafruit.com/product/3333)
**Circuit Playground Express** is the next step towards a perfect introduction to electronics and programming. We've taken the original Circuit Playground Classic and made it even better! Not only did we pack even more sensors in, we also made it even easier to...
In Stock
[Buy Now](https://www.adafruit.com/product/3333)
[Related Guides to the Product](https://learn.adafruit.com/products/3333/guides)
### Circuit Playground Bluefruit - Bluetooth® Low Energy
[Circuit Playground Bluefruit - Bluetooth® Low Energy](https://www.adafruit.com/product/4333)
**Circuit Playground Bluefruit** is our third board in the Circuit Playground series, another step towards a perfect introduction to electronics and programming. We've taken the popular Circuit Playground Express and made it even better! Now the main chip is an nRF52840...
Out of Stock
[Buy Now](https://www.adafruit.com/product/4333)
[Related Guides to the Product](https://learn.adafruit.com/products/4333/guides)
### Micro Servo with Alligator Clips
[Micro Servo with Alligator Clips](https://www.adafruit.com/product/5592)
This servo is [just like our classic Micro Servo](https://www.adafruit.com/product/169) but has 3 alligator clip test leads at the end! This makes it perfect for plug-and-play support with any of our boards with alligator-clip-friendly input/output pins, like the
In Stock
[Buy Now](https://www.adafruit.com/product/5592)
[Related Guides to the Product](https://learn.adafruit.com/products/5592/guides)
### Circuit Playground Bolt-On Kit
[Circuit Playground Bolt-On Kit](https://www.adafruit.com/product/3816)
You have a [Circuit Playground Express](https://www.adafruit.com/product/3333), but you need to mount it to your charming cardboard robot friend, eh? Not so easy if you don't have a set of standoffs!
In this kit comes:
- 6 x M3 12mm brass hexagonal...
In Stock
[Buy Now](https://www.adafruit.com/product/3816)
[Related Guides to the Product](https://learn.adafruit.com/products/3816/guides)
### Fully Reversible Pink/Purple USB A to micro B Cable - 1m long
[Fully Reversible Pink/Purple USB A to micro B Cable - 1m long](https://www.adafruit.com/product/4111)
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 not having to flip the cable around.
First let's talk about the cover and over-molding. We got these...
In Stock
[Buy Now](https://www.adafruit.com/product/4111)
[Related Guides to the Product](https://learn.adafruit.com/products/4111/guides)
### 3x AA Battery Holder with On/Off Switch and 2-Pin JST
[3x AA Battery Holder with On/Off Switch and 2-Pin JST](https://www.adafruit.com/product/4779)
Here's another addition to our growing family of [AA battery holders](https://www.adafruit.com/category/563). Behold! A holder for three (3) AA batteries! It's got a 6" long genuine JST-PH 2-pin cable connector, an On/Off switch, and, oh yes, it's in...
In Stock
[Buy Now](https://www.adafruit.com/product/4779)
[Related Guides to the Product](https://learn.adafruit.com/products/4779/guides)
### Alkaline AA batteries (LR6) - 3 pack
[Alkaline AA batteries (LR6) - 3 pack](https://www.adafruit.com/product/3521)
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 of **3 AA batteries**.
These batteries are Alkaline (MnO2) chemistry, with a voltage...
In Stock
[Buy Now](https://www.adafruit.com/product/3521)
[Related Guides to the Product](https://learn.adafruit.com/products/3521/guides)
## Related Guides
- [Adafruit Circuit Playground Express](https://learn.adafruit.com/adafruit-circuit-playground-express.md)
- [Adafruit Circuit Playground Bluefruit](https://learn.adafruit.com/adafruit-circuit-playground-bluefruit.md)
- [CircuitPython BLE Libraries on Any Computer](https://learn.adafruit.com/circuitpython-ble-libraries-on-any-computer.md)
- [Illuminated City Skyline with MakeCode](https://learn.adafruit.com/city-skyline-with-makecode-for-cpx.md)
- [Creating and sharing a CircuitPython library](https://learn.adafruit.com/creating-and-sharing-a-circuitpython-library.md)
- [Color Remote with Circuit Playground Bluefruit](https://learn.adafruit.com/color-remote-with-circuit-playground-bluefruit.md)
- [Cartoon Network and Make Code - Rose Quartz Shield Umbrella](https://learn.adafruit.com/cartoon-network-and-make-code-rose-quartz-shield-umbrella.md)
- [CircuitPython Hardware: SD Cards](https://learn.adafruit.com/micropython-hardware-sd-cards.md)
- [Cardboard Circuit Playground Express Inchworm Robot](https://learn.adafruit.com/cardboard-robot-inchworm.md)
- [Esenciales para CircuitPython](https://learn.adafruit.com/esenciales-para-circuitpython.md)
- [SpaceX Helmet](https://learn.adafruit.com/spacex-helmet.md)
- [UART Communication Between Two CircuitPython Boards](https://learn.adafruit.com/uart-communication-between-two-circuitpython-boards.md)
- [Circuit Playground Powerpuff Girls Valentine](https://learn.adafruit.com/circuit-playground-valentine.md)
- [Circuit Playground Express Rocket Lamp](https://learn.adafruit.com/cpx-rocket-lamp.md)
- [TFT Gizmo Animated Eye](https://learn.adafruit.com/tft-gizmo-animated-eye.md)
- [Tappy Robotic Hand](https://learn.adafruit.com/robotic-tapping-hand-with-cpx.md)
- [Stroboscopic Zoetrope](https://learn.adafruit.com/strobe-zoetrope.md)