"In mythology, the Muses were nine goddesses who symbolized the arts and sciences. Today, a muse is a person who serves as an artist's inspiration."

Person?

What about all the Cats in Engineering?

 

If you have mad pet allergies (like me) you might have to make a hypoallergenic muse... er... cat.

Like Wizzy!

 

Supplies can be had on Amazon, eBay, Etsy, and Michaels. 

Remaining tools and electronics can all be purchased in the Adafruit store.

Wizzy the Cat is a substantial / advanced project that spans animatronics, electronics engineering, software engineering, and needle felting. This project may take three or more weekends to complete!

Wizzy's 3D printed parts can be printed without support, minimal infill, and ~3 shells. Before we dig-in, I've broken the 3D Printed Animatronic Tail out into a separate guide.

Build that first...

Tinkercad: 3D Printed Animatronic Tail

Our head mount is simple: head plate, flanges, and a frame for a standard-size servo. Again, no support, minimal infill, and ~3 shells should be plenty strong.

Tinkercad: Wizzy the Cat Head Mount

The bottom (body) flange is for the 21 mm dowel and the top (neck) is for the 12 mm dowel

Needle Felting can be a little scary, especially at the point where your confidence and pokes-per-second exceed your attention span.

Here, a quick reminder to take your time...

Needles push or pull fibers, compacting the felt as you go. (They'll work just as well compacting right into your finger!)

Buying an assortment with at least one of each of the following is a good place to start.

  • Triangular - barbs on three sides that are good for general detail
  • Star / Square - barbs on four sides that are good for coarse work
  • Spiral - good for quick and firm felting
  • Reverse - barbs are reversed to pull fibers out rather than in

Generally, detail is determined by the size or gauge of the needle. 

As you can see... I have not graduated (yet) to anything smaller than 36 gauge.

Needle felting starts with fiber... like wool, which is amazing stuff! But for some reason, it's difficult to find a source for smooth, consistent, and beautifully colored fiber.

Etsy is my go-to for batts and roving.

Pull just a bit from the end... too far in and the fiber resists separating.  

Vary the angle of the needle as you felt to develop strength in all directions. Using sponges, brushes, and even felt craft-sheets as a backer / base can help get things started.

So... let's throw-down some tufts of wool and get poking!

Grab your pliers and pipe cleaners... and hot-glue the animatronic tail to the 10 inch base.

Your frame needs to be solid / stiff, which may require doubling-up on pipe cleaners - two or three should be sufficient. 

Twist them together, staggering the overlap for maximum strength and rigidity. 

Start, by building a loose 'hoop' around the base.

Next, add a sturdy loop on both sides... this is where the hind legs meet the body. 

Slap some feet on, and begin adding sculpted horizontal, vertical, and cross-cross pipe cleaners - overlapping at least three or four times!

Continue, until your reach the base of the tail and neck.

Pretty is not the goal here... only strength and general shape! 

Place small but long tufts of fiber over the outside of your frame and felt from all angles to maximize strength and compactness. Work from the inside-out or use a reverse needle if the felt begins to sag.

Keep adding felt until the body is completely opaque. Coarse needles move a lot of fiber but tend to leave the surface ragged; you can smooth everything out nicely with a smaller gauge needle.

Here is what we are aiming for... let's work on the feet next!

Grab a sheet of black craft-felt and cut a rectangle about two-inches wide and long enough to cover the leg - rolling it around the leg as shown.

Sheets of felt can be joined / tacked together with a few vigorous pokes.

Thicker legs are easy, just increase the number of wraps around the pipe cleaner. When you are satisfied, go over the seam until it disappears.

Craft felt sheets are pretty rough... you can add a thin layer of roving / fiber on top to finish the job.

Fill gaps between the leg and the body for maximum strength and cuteness.

Use a 3/16 inch drill bit to make mounting holes in the flange that match the hole pattern in the servo. We could have 3D printed these... but hole patterns are a moving target. 

Drill another hole about half-way up flange to secure the neck dowel in place. 

Repeat these steps with the base flange and install the servo.

Extra screws left-over from micro-servos are great for holding the 12mm dowel in place. Hot-glue works nicely as well.

Make sure to check the height of the dowels as you go... the neck flange needs to be just above the hole at the base of the neck.

Grab some milk and cookies as a reward for your work so-far... you are in the home-stretch!

In my zeal to make the body frame strong, I ran out of white pipe cleaners. Remember, we are going to cover all this with a layer of felt.

No big!

Use the same framing technique on the head as you used on the body.

Reference drawings can be helpful, but only if you measure every now-and-again to make sure you are on target.

Serviceability is a good thing to keep in mind... if something breaks, how hard will it be to fix?

A good example, would be adding a speaker grill if you don't have one - making it much more difficult to puncture the delicate cone.

Use enough hot-glue to mount components securely... somewhere between temporary and permanent.

And... a little more generous on components that vibrate!

Use some more hot-glue to affix the upper neck flange to the head-plate. Glue the 12mm dowel into that flange keeping it perpendicular to the base and centered (roughly) within the neck.

This is my favorite stage of a project, where personality starts to emerge!

We are going to use the last of our felt sheet for the head... stitching pieces together as needed to maximize natural contour.

Felt is such an amazing medium to work with... a simple needle becomes a sewing machine!

Cut, trim, and seam as needed until the head is covered. Mistakes are easily fixed - pull the felt until it overlaps a bit and poke! poke! poke!

Add your eyes and cover the head with roving - just like the body. 

We are going to have to do something about those eyes... kinda creepy don't you think?

Two things!

First, our tail is going to wag back-and-forth... a tight fit may have an undesirable result - felt loosely for free-flowing movement.

Second, watch the angle of your felting needles. We don't want to damage the tube underneath or break a needle on a hard plastic piece.

Especially on the tip of the tail.

You could attach the tail directly to the body... but for sake of serviceability I'm going to make a 'port' for the tail to slip-through.

If you need to service anything inside Wizzy, all you will have to do is loosen one screw (neck base / servo) and slip the body over the tail. 

Seams can be hidden fairly well if you build-up the rim until it's snug around the tail.

Eyelids... hoping to convey a groovy mood.

For whiskers you could use a bit of stiff fishing line... or you could extrude a bit of filament manually from your 3D printer. Dab the end in a bit of school glue and poke into place. 

Ears were difficult for me... my first attempt looked like bunny ears. Second attempt looked like something you might find on Piglet. Finally, I added a pinch of white on the interior of the ear to give it a little shape - and called it done.

I added some tufts of felt on the cheeks which turned out nicely. Anyone remember Bill the Cat?

 

If somone just walked into the room at this point and said, "awwww!" You're on the right track!

Not part of my original plan, but I'm going to load-up the front feet with a few beefy washers to keep them from flopping around as the tail wags back-and-forth. 

If you're [ pick one or more: obsessive, compulsive, picky, detail oriented, excessively caffinated], you can cover the ugly with a bit of felt sheet.

As well as the base, for ultra-fuzziness!

When Wizzy guards the Halloween candy bowl at our house, I use an RC transmitter / receiver - which allows me to interact 'personally' with trick-or-treaters.

Electronically, Wizzy is pretty simple... two servos and an audio trigger. 

This setup will perform a tail-wag, head movement, and offer a snarky comment. Make sure to use a 5V power supply that can provide a constant 2 AMPs or better. 

You can use just about any Arduino compatible!

Download: file
#include <Servo.h>

// head and tail servo objects
Servo head;
Servo tail;

// variables used to track the position of the head and tail servos
int hpos = 0;
int tpos = 0;

void setup() {
  // attach head and tail servo to digital pins 9 and 10 respectively
  head.attach(9);
  tail.attach(10);
}

void loop() {

  delay(5000);

  // wag the tail back and forth - adjust range as needed
  for (tpos = 0; tpos <= 180; tpos += 1) {
    tail.write(tpos);
    delay(15);
  }
  for (tpos = 180; tpos >= 0; tpos -= 1) {
    tail.write(tpos);
    delay(15);
  }

  delay(5000);

  // rotate head left and right - adjust range as needed
  for (hpos = 0; hpos <= 180; hpos += 1) {
    head.write(hpos);
    delay(15);
  }
  for (hpos = 180; hpos >= 0; hpos -= 1) {
    head.write(hpos);
    delay(15);
  }

  delay(5000);

  // trigger random audio playback
  analogWrite(0, -255);
  delay(15);
  analogWrite(0, 0);
}

Use these audio files if you like... the Audio FX board will randomly play one of them when Trigger 0 goes LOW.

So many ways to drive Wizzy... Bluetooth, PIR sensors, laser triggers, flex-sensors, vibration switches, Infrared, and accelerometers.

If you make your own animatronic pet, I would LOVE to hear about it!

This guide was first published on Nov 21, 2016. It was last updated on Nov 21, 2016.