Animated Jack-O-Lantern

I wanted a more interesting and re-usable jack-o-lantern for my house. After seeing the Adafruit Monster Mask, I knew what I had to do.

PARTS

Plastic Pumpkin - Michael's

Monster Mask Kit - Adafruit

JST SH 9 Pin Cable 100mm long - Adafruit

Acrylic and Hardware Kit for Monster Mask - Adafruit

Convex Lenses for Monster Mask - Adafruit

LED Lights - Amazon

USB Splitter - Amazon

USB A -> USB Micro B Cable - Amazon

HVAC Duct Cap - Home Depot

Milwaukee Battery to USB Adaptor - Home Depot

Milwaukee M12 Battery - Home Depot

TOOLS

1-1/2" hole saw - Home Depot

6" Hole Saw Optional - Home Depot

Zona Saw - Micromark

Dremel EZ Lock sanding discs - Home Depot

Dremel EZ Lock Mandrel - Home Depot

3/8" Drill of your choice.

Rotary tool of your choice.

MISC

Hot Glue

Pencils / Markers

Masking Tape

I'm definitely not a stickler on specific tools and materials, the ones listed above are the ones I used, you may have better results with others. Just one promo for the Micromark Zona saw. The smallest blade worked really well cutting this plastic pumpkin. Not a bad purchase if you anticipate cutting small items that need a gentle touch. They also have other thin blades which makes it perfect for cutting tabs after doing items on my CNC.

I purchased the pumpkin from Michaels but I'm sure they sell them at other craft stores. They are really good bases for projects like this (re-usable jack-o-lanterns.) They are both sturdy after being cut as well as easy to machine/cut/shape.

Once I got the pumpkin, I used masking tape to work out a face, before cutting.

NOTE: The eyes from the mask unit are a specific width apart when you get them, but you can cut them apart to increase the spacing. (I did that step(see below) before completing the final face design. So the two main things to consider regarding the eyes is that they can only go so close or so far apart, AND, consider whatever you plan to back the other holes (nose and mouth) with. Later you'll see how I di this, but it was important there was enough space between the eyes and nose so their backings didn't interfere.

After the design was completed with tape (and approved by my 9 year old daughter) on the "façade," I started cutting things out.

I started with a 6in hole saw to create the access hole in the back, you could also use some smaller holes and connect them with saw cuts, or just use a saw to cut out the whole panel. I used the "offcut" to test holes for the eyes. Which is a good ides since you might not know how thick the pumpkin is, and how it will interact with the lenses on your LCD's. I tested 1-1/2" and 1-3/4" and for the parts I used here, 1-1/2" was the better choice, just enough of the lens protruded and there was much less gaps on the edges. And as with any hole saw, go cautiously, so the drill doesn't twist your arm off.

The nose and mouth were much easier, just drill a hole interior to the opening for the initial saw cut to start from and hand cut out the shape. The saw listed in the supplies, cuts well, but it's not the greatest at plunge cuts, so drill a pilot hole whenever possible.

So the last step is to remove the internal structural ribs from the inside of the pumpkin to allow the eyes, to sit flatter and thus closer to the interior of the pumpkin and letting the lenses come through to the façade more. I set each eye in it's proper hole (they do have a right and a left) and traced around the outside edges of the eye module, Once I had them traced I could use my rotary tool with some Dremel EZ-lock sanding discs to smooth out the ribs in those areas. I specify the ez-lock system here because it doesn't have a shaft/mandrel that protrudes on the sanding side of the bit, getting me flat surfaces faster, Speeds of 2 on this plastic work just fine with the plastic/foam on these pumpkins.

You can start HERE for the Monster Mask guide from Adafruit. They provide info on customizing everything from eye type to size and pupil reactions to light sensors. I'll be honest this year I didn't have time to do any of those things. I simply used the kit right out of the box. It comes with the eyes you see below - preloaded, just plug the board into USB power and they boot and start moving within 10 seconds.

I purchased the lenses and the acrylic mounting kit (more here), the lenses really help give a more 3d appearance than just the LCD's. Adafruit has more info about how to 3d print your own lens holders, but the ones they stock are pretty cheap and I didn't care about their appearance, only that they would hold the lenses in place and provide a surface to hot glue into the pumpkin.

My order of assembly was the following.

1. cut the mask apart with side cutters on the "perforations"

2. Install the lenses and acrylic lens holders.

3. install the 100mm JST cable between the now two piece board so that the eyes can be spaced apart and match the curved inside surface of the pumpkin

Now you're ready to figure out your mouth and nose.

Ok, apologies for not taking a good photograph of this part of the project. Let me explain what's going on here.

So I knew that I needed openings for a mouth and nose, AND I knew I would have an access hole at the back, so I determined I needed to create a "back" for those other openings and that it needed to be lit from behind such that the light source wasn't visible. How you choose your mouth and nose come into play here, the bigger or smaller they are will change what you need to use as your back and lighting. I went through a couple of different items and ended up with the HVAC duct cap shown here, it was 1. rigid enough to work with, 2.big enough to cover all the openings AND 3. Just small enough to fit through the access hole I made in the back. I think perhaps the rigidity was the most important characteristic of the piece (more on that later.) Either way you'll have to consider those issue when determining what works best for you.

I purchased the cheapest USB powered light strips I could and used just one length. The control board is attached securely to the first strip (I would recommend using one of the connector cables to move that board to a more convenient location if possible.) so I had to wrangle with it since it keeps that joint from conforming to the circle of the duct. I ended up running it through a hole to the outside and taping it down such that it bent out and the LED strip bent in, it worked ok. The LED strip had a sticky back so I just peeled it off and applied it to the inside edge of the duct about 1/2 way from front to back (trying to minimize how visible they were)

So with the eyes and the mouth backing completed, I proceeded to assemble the whole pumpkin.

I started with the eyes, since I had "flattened" the surface, I applied a strip of hot glue around the edge and pressed the eye into it..

Once I started to try and install the mouth backing, I realized I should smooth out the surface it attaches to. I used the same technique described above (Inserted duct piece, traced line around duct, removed piece and sanded with rotary tool) then applied hot glue and installed that duct piece that just like the eyes. Now I make that last operation sound pretty easy, but it was actually pretty challenging. This is one of the things I would modify for next year's version - I believe instead of an access hole in the back, I would split the pumpkin down the sides from the bottom and then around a circle at the top.

All that's left is to attach the cables to the battery. The monster mask takes a USB micro b connection, I used a short jumper to attach it and the lights to the splitter and then the splitter to the rechargeable power tool battery (I already had this so feel free to use your USB power source of choice) I had a 3Ah battery and it lasted the entire night. Next year when I have it up to display longer I might switch to a larger battery and probably 18v (the added weight will help hold it in place as well.)

Plug in the battery pack, set in place to display, and enjoy the comments from parents and trick-or-treaters.