No one likes it when someone or something comes up from behind you unexpectedly. Since most people do not have a fine-tuned spidey-sense, add electronics to detect when there is something lurking out back. Protect your six.
Because it is so cold outside and everyone is inside contemplating on doing the latest organizing and cleanup craze, I found an old pair of earmuffs that had some earphones built in, a warm and cozy set of headphones. And bonus, it was covered in plaid fabric. Hmmm, I guess it could spark some joy if I made something out of it.
Taking inspiration from Adafruit guides on making animatronic ears:
Here is my take on personal security with a werewolf plaid theme...
And if you do happen to encounter a werewolf, heed the words in the poster from Adafruit's resident werewolf @PaintYourDragon.
Step 1: My, What Big Ears You Have...
No lasercutter or 3D printer available to use? I hear ya. Just craft the ears out of cardboard and glue.
I'm always interested in animatronic setups so I made my own cardboard version of the pop-up ear mechanism from Dave Astels shown in the Adafruit guides.
I used some elastic cord I found(probably the kid's hairband, I'll get her some more...) as the rubber band return spring. I used kite string as the pull cord since it has no noticeable stretch to it. The tip of soldering a wire ring to pass connect the cord to the servo control horn was good as it made things so much easier to work with.
The servos are mounted in cutouts in the cardboard ear form and taped in the slots.
As with all things mechanical, this wonky setup needs to be calibrated and fine tuned to get the movements working right. Using Circuit Python is great in the iterative process as you can quickly change the code settings for the servo movement and adjust as necessary.
Step 2: Guide to the Guides...
I had met Mike "Buy my Book" Barela, author of "Getting Started with Adafruit Circuit Playground Express" at the last World Maker Faire. He kindly gave me an Adafruit Gemma M0 board. This would add to my arsenal of Arduino boards I use for making stuff, especially light-up neopixel stuff. Having it would allow me to do more Circuit Python too.
Since the Gemma M0 has only 3 free pins and if you want the smallest form factor board to drive a few things, this board would be perfect for a wearable project. I am going to drive 2 microservos for the ear movement and get readings from a PIR(passive infrared) sensor for motion detection.
I wired up my electronics. I am using a 3xAAA battery pack as I don't have a LiPo rechargeable battery pack to use as it would make the setup even smaller. I used the twisted strands from the core of CAT-5 ethernet cable, I'm still trying to use up a 1000' foot bulk spool I purchased a long time ago. To connect to the female connectors already on the servo, I have the Dupont connectors and crimper to make up the male connector on the wires coming from the Gemma M0 board. Adding connectors to break the connection of the servos is useful when you connect the board back up to USB for programming. Because the program autoruns when the board is powered up, if you have the servos running, it may be too much of a power drain which may cause "the fuse to blow" on your USB port and shut it down.
I combined the Circuit Python coding examples to get things up and running. First, I got my PIR sensor working to blink the onboard LED and Dotstar LED. I then added the code to drive the servos which would move when the PIR sensor detects something.
My code here:
You might be interested in making other related ISO Standard Werewolf accessories and items:
Wind collar add on for cold weather jackets or if you just want to look cool and faux fashionable:
Holiday stocking decoration with wagging tail:
Werewolf backpack with wagging tail:
Step 3: Dress It Up...
Cut out some craft fur and material to cover the ear. I just sewed the some scrap pieces together but you can experiment with a more refined pattern and make the cover more form fitting.
Mount to the earmuff/headphones with adhesive backed velcro or any way you can.
You will find you need to tune the movement of the ears again because the craft fur and fabric covering the ear will change how the servos will act. You may need to adjust the tension on your return spring or pull cord.
Secure the electronics and wires in position with tie-wraps.
Now go out there and be fierce. Don't worry about people sneaking up on you. Ok, you should.