Breathe some life into your Halloween decorations by making an ordinary pumpkin play an animation! No electronics, no strobe lights; you just need a lamp, a pumpkin and something to spin it on.
This Halloween, I wanted my jack-o'-lantern to stand out from the crowd without drifting too far from tradition. I wanted it to be hand-carved and I wanted it to be made from a real pumpkin. I also wanted it to move.
I think it should be a good conversation piece at any Halloween party, giving the guests something interesting to play with in between eating horrifying foodstuffs and awkwardly seducing masked strangers.
The mechanism for this jack-o'-lantern is very simple, falling somewhere between a zoetrope and a film projector. Unlike a normal zoetrope, where you have to look through a series of slits to view a moving image, my jack-o'-lantern shines an external flashlight up through the slits to illuminate the pumpkin's innards. As the pumpkin rotates, its insides are only lit whenever one of the slits aligns with the flashlight, causing it to flash in time with the frames of an animation carved into the pumpkin's skin.
One of the neat things about this design is that it automatically syncs the flickering light with the animation, regardless of how fast you spin the pumpkin. This means that it requires no fiddly electronics or separate mechanical shutter mechanism; it will flash exactly as fast as it needs to flash when you spin it by hand. The blurry video here doesn't do it justice - the effect really needs to be seen to be believed!
Now! Keep reading for full instructions on how to make your own...
Step 1: The Four Stages of Gourd-quickening
Just how long will this project take?
That really depends how much effort you want to put into it and what materials you already have to hand. There are four stages to making an animated jack-o'-lantern, but you can optionally skip or at least dramatically shorten some of them. This could be an evening project or a whole weekend project, depending how you feel.
1. Designing and drawing your animation
For me, this was by far the most time consuming part of the project. If you want to carve your own design into your lantern, it will require a solid understanding of frame-by-frame animation as well as the ability to draw a coherent animation in a very limited number of frames. If you'd rather skip this step, the internet is full of short animated gifs just waiting to be stolen and turned into Halloween decorations. Of course, I'll also provide the animated bat template I used to carve my own pumpkin, meaning you can move straight on to step 2.
What you need: Printed or drawn images of each frame in your animation, scissors.
2. Building/finding a turntable
This is where you'll probably have to use a bit of ingenuity. You need to find a way of spinning your pumpkin (I feel that should be a euphemism for something, but I'm not sure what). How you do it is up to you.
There are many different ways you could build a pumpkin turntable. My method was guided entirely by what I had lying around the house. You may come up with a better design (e.g. using a lazy Susan, a power drill or an old bike wheel), or you may already have a suitable turntable at home (e.g. a record player or a pottery wheel).
The key features of a DIY turntable:
- it can support the weight of a hollow pumpkin
- it has a means of attaching said pumpkin
- it can rotate at a speed of around 50-100 rpm
What you need: Something spinny.
3. Carving the pumpkin
This part is unavoidable but surprisingly straightforward. Expect to spend a couple of hours hollowing and carving your pumpkin. I recommend setting aside some time to make delicious soup from the flesh of your pumpkin.
What you need: Pumpkin, big knife, big spoon, sharp craft knife/scalpel, sticky tape.
4. Setting up the lighting
After you've done all the hard work, you still need to light your jack-o'-lantern. This is not hard, but it can be fiddly and it makes a huge difference to the final appearance. Allow at least 40 minutes for fine-tuning and don't leave it until the last minute.
What you need: Flashlight (preferably LED), cardboard box, scraps of opaque card, opaque black insulation tape.
Still with me? Have everything you need? Wonderful! Let's go!
Step 2: Using Pre-drawn Animations
"How to draw animations" is a subject people can (and do) spend their whole lives studying, so I won't try to condense it into a single Instructable. Instead, I'll focus on the details which are relevant to making a zoetrope. If you'd rather not draw your own animation, feel free to use one of the animations I've provided.
I can offer you "flapping bat" or "angry molesting tree". I would only suggest trying to make the latter if you have a very large pumpkin and a lot of patience. I drew the bat by digitally rotoscoping some live action footage of a real bat in flight. The tree was drawn from my own imagination as an homage to The Evil Dead by way of Cabin in the Woods.
To recreate my animations, download the images from this step and resize them so that the image width is equal to the circumference of your pumpkin. Print them out and you're good to go!
You may have noticed that the bat animation only has 15 frames, whereas the tree has 16 frames. How can they then be combined into the same animation? I'll come back to that...
Update: I have added a new animation of Baba Yaga's house walking along on its chicken legs and puffing smoke from its chimney. I made this using a combination of hand-drawn animation in Adobe Flash (after hours spent studying bird gaits on YouTube) and 3D modeling in Autodesk Fusion 360 (to make the house twist smoothly and consistently from side to side as it bobs along with the legs).
Step 3: Looping Animations
One major disadvantage of animating on a zoetrope rather than on a filmstrip is the space limit. If you're carving each frame of your movie into the side of a pumpkin, it won't be long before you circumnavigate your gourd and end up overlapping with the first frame again. There are a few ways you can deal with this issue:
- Make every frame in your animation smaller, so that they all fit around the pumpkin's equator.
- Have your frames spiral upwards around the pumpkin so that they don't overlap until the curvature of the surface starts doing weird things to your movie.
- Plan ahead and choose a movie which is very short and seamlessly loops with itself. By this I mean that the transition between the final frame back to the first frame appears just as natural as the transition between any other two adjacent frames.
Option 1 is useful up to a point, but you'll quickly be limited by the physical constrains of your manual dexterity and your pumpkin's structural integrity.
Option 2 is interesting to design, but very hard to use effectively. It also turns looping into a nightmare*.
Option 3 is likely to be the best solution. Looping animations are much less jarring to watch and can run for longer with fewer frames. For the sake of convenience, I recommend making a simple, looping 16-frame animation. On a pumpkin, using 16 frames gives you a good compromise between animation smoothness and frame size.
*If you're wondering, the way to get round this is to arrange your frames in a folded figure-of-eight and cleverly pick a frame that appears twice in the animation to be the intersection point of the two loops. It is awkward and unnecessarily showy. I love it.
Step 4: Catching the Drift
In a traditional zoetrope, unlike a film projector, every frame of the movie can be viewed at the same time. A 16-frame movie in effect becomes 16 identical movies running side by side, a single frame out of step with each other. The real fun begins when you start animating characters who can step between these movies, gradually working their way around the zoetrope until they come back their original movie. It adds a whole new dimension of motion that you cannot reproduce on a flat screen. So how do you achieve this effect?
The answer is surprisingly simple. If you play a 15-frame animation in a 16-slit zoetrope, the start of each successive frame will be slightly further out of sync with the original frame, so the movie will appear to drift in the direction opposite to the zoetrope's rotation. However, it will still loop round to its original position after a full rotation, creating the effect of having stepped one frame sideways over the course of a single loop. As if by magic, its neighbor will have stepped in to take its place and the cycle can continue!
(Conversely, if you play a 17-frame animation in a 16-slit zoetrope, it will appear to precess in the same direction as the zoetrope's rotation. You'll face the problem of fitting the extra frame into the limited space, however.)
By combining the 15-frame animation of a flapping bat with a 16-frame animation of a tree, we can create the impression of 15 bats constantly flying in a circle over the heads of 16 firmly rooted trees. Notice how where the bat would have frame 16 it instead has frame 1 again, only shifted to the left.
There's no reason you can't have characters walking into two different directions in the same zoetrope. One of the finest examples of this is Pixar's wonderful 3D-printed zoetrope. That has given me great ideas for next year's even more elaborate pumpkin carving...
Step 5: Making a Turntable
Once you know what animation you will be using, it's time to build the machinery to display it with.
As I mentioned before, my turntable design was guided entirely by what I had lying around my house. In my case, this included scrap wood, steel rod, omnidirectional caster bearings and a pair of 3D-printed bevel gears. If you also happen to have all of these components then you are clearly living an awesome life and I think that we should be friends. Message me.
If not, you'll have to improvise for the next few steps. Don't worry - I have faith in you.
Step 6: Start With a Base
However you decide to build your turntable, it will need a steady base to stand on. Make sure it is at least 30 cm wide and can be taped or clamped to the table.
I screwed together four strips of wood, then added panels on top to keep them square. Well, square-ish. It was anything but precise.
Step 7: Get Your Bearings
A turntable needs a way of turning, so you'll probably need some kind of bearing to support the rotating pumpkin platform. I recommend using a lazy Susan bearing if you have one, but I ended up using furniture casters to support a platform which spun around an axle attached to a pillow block and a radial ball bearing.
Step 8: Feeling Cranky
Your turntable also needs a way to let you power it. You might choose to do this by hand, or using a motor. A quick and dirty hack would be to attach an electric drill to a length of rod and call it a day. A simple drive belt or a bicycle chain would also be good ways to connect your rotating tool to your turntable. Remember: You don't need to be able to precisely control the speed of rotation because the strobe effect will sync up with the frames however fast the pumpkin is turning.
If you have access to a 3D printer, you can make the same pair of bevel gears that I used. I found them online at Thingiverse and added a frame to hold them in place. You can use my STL file or the original from staffert's Thingiverse account; just remember to adjust the size to fit your axles.
Step 9: The Pumpkin Platform
The platform on which my pumpkin sits was made by screwing together a few scraps of wood and taping them to the central axle, keeping the tape sandwiched between the two layers of wood. Those four dangerous-looking upward-pointing screws are to hold the pumpkin in place.
Important step: Draw lines through the center of your platform to divide it into an even number of segments. Each segment will represent a single frame of your animation. If your animation has 16 frames, draw 8 lines to divide the platform into 16 segments.
Try to make each segment the same size, but it doesn't matter if they're a little different as long as the lines are all straight and passing through the platform's center of rotation. These lines will mark where to carve the lighting slits on one side of the pumpkin and the corresponding animation frames on the other side, so it's vital that they are straight.
Step 10: Choosing a Pumpkin
You've sort out your animation? You've built/found/stolen a turntable? Fantastic - the hard part's done! Now it's time to pick up a pumpkin. Choose wisely, considering for the following:
- Size - a bigger pumpkin gives you more space to carve. This means you can have a longer animation and/or a larger image area. It may, however, require a bigger turntable.
- Shape - the rounder the better.
- Freshness - look carefully for squishy patches which might compromise your carving later on.
Step 11: Hollow and Mount
Scalp your pumpkin, scoop out its brains and mount its empty skull on your turntable as a warning to other fruit. Try to make its wall very thin where you'll be carving your animation, but reasonably thick and sturdy elsewhere.
Step 12: Divide and Conquer
Now you need to divide your pumpkin into precisely aligned vertical segments. If you happen to have a laser capable of projecting a line (such as you might find on a circular saw or a laser-guided machete), then you can use this to help you. Otherwise, you can use anything sturdy with a right angle and steady hand.
Remember those dividing lines you drew earlier on your pumpkin platform? You're now going to draw a line up the side of your pumpkin starting at the end of each of those dividing lines. Make sure you draw them all as vertically as possible, using a fixed point of reference (i.e. your laser or your right-angled object) as a guide. Imagine a vertical plane defined being projected up from one of those dividing lines - wherever that plane intersects the surface of your pumpkin is where you'll draw your line, even if the surface is wonky.
The goal here is to create points of reference for where to cut your slits and your animation frames so that they can precisely align with the narrow beam of light you'll use to illuminate the jack-o'-lantern. It's worth taking the time to get this right rather than just eyeballing it.
Step 13: Criss Cross
As well as drawing your lines of longitude, you should mark three rings of latitude. One of these will be a reference point for your animation frames, while the other two will mark the top and bottom of the light slits. The tops of the slits should be about half way between the pumpkin's equator and its south pole.
Step 14: Print Out Animation Frames
Measure the circumference of your pumpkin and check that all of your animation frames will fit around the equator. If necessary, resize them. Print the frames, cut them out and tape them in place around the pumpkin, using the lines you've drawn on the surface to guide you.
Make sure you place the frames in the right order, taking into account which way you intend to spin your pumpkin.
Side note: In the picture here, the printed frames are actually out alignment with the lines on the pumpkin. The vertical lines in each frame should lie along the lines drawn on the pumpkin.
Step 16: If You Prick Us, Do We Not Seep?
Transfer the images onto the surface of your pumpkin by carefully perforating around them with a needle, creating a dotted outline of each frame on the fruit's skin.
Step 17: Carve Away
Using a scalpel or a fine craft knife, cut out each frame.
You also need to cut out the slits around the base now. Try to make them as narrow as you can. The wider these slits are, the more light they'll let in. This might sound like a good thing because it will make the jack-o'-lantern brighter (which it will), but it will also mean that each frame of your animation will be lit for longer as it moves in front of the light, causing it to blur. This is analogous to the shutter speed of a camera; we're trying to capture a moving image, so we need a fast shutter speed (i.e. narrow slits).
In my jack-o'-lantern, I accidentally made the slits too wide. As you can see, I solved this by redefining them with insulation tape later, making them narrow again. That actually had the advantage of letting me tinker with the exact slit width, but it looks pretty darned ugly. If you can get the slit width right first time, you won't need to cover your pumpkin in tape. If not, don't worry about it! You can always fix it just like I did.
Step 18: It's Time to Light the Lights!
Everything is assembled and you're almost there! All that's left to do is set up the lights. This is extremely simple, but may require some fine-tuning.
Make a crude slit-lamp by cutting a vertical slot in the side of a cardboard box and placing a flashlight inside, pointing out of the slot. Use pieces of card as shutters to turn the slot into a slit, which you can adjust later. There should now be a tall, thin beam of light shining out of the box.
Place the box behind the pumpkin so that the beam of light points through one of the pumpkin's slits and aligns with the pumpkin's axis of rotation. Adjust the light's shutters so that the beam doesn't accidentally shine through the animation carvings, creating unwanted ghost images (the annoying optical kind, not the spooky Halloween kind).
Finally, you need to provide a screen for the light to shine on. Place a thin layer of facial tissue (as in Kleenex, not skin) over the inside of each of your carved animation frames. It should stick to the pumpkin flesh on its own, but you can pin it in place if necessary.
Step 19: Take It for a Spin
Dim the house lights, crank the handle and behold the magic!
Or, if you're like me, be upset that all you can see is a blurry circle spinning around the pumpkin! Then get a snack to cheer yourself up and set about fixing the lights. Possible causes of blurriness include:
- The slits in the pumpkin are too wide. Make them narrower with tape.
- The slit in your slit lamp (cardboard box) is too wide. Make it narrower with card and tape.
- The flashlight is too close to the slit in the box, giving your slit lamp a wide beam. Move the flashlight further back into the box.
- You need glasses. Consult an optician.
You'll notice that most of these fixes will make your jack-o'-lantern slightly dimmer. Just like in photography, there is a balance to be struck between image sharpness and image brightness. Fortunately, jack-o'-lanterns are naturally nocturnal so they do not have to be very bright at all to still be seen clearly.
That's it! You're done! I hope you enjoy showing it off to friends and family. Now it's time to start worrying about your Halloween costume...