Introduction: Simple Animatronic With Micro:bit
Welcome to my first Instructable. I’ll be sharing how I made this Skeksis Animatronic. By guiding you through my whole process it is my hope that you’ll be inspired to make your own robot even if it looks nothing like this. I will not talk much about how to create the artwork, this is more focused on how to combine it with electronics.
This project was inspired by the absolutely gorgeous series The Dark Crystal: Age of Resistance. You should check it out, it’s breathtaking. I especially recommend watching the behind the scenes for jaw-dropping beautiful and creative artistry on display.
Combining art and tech is very easy nowadays. There are lots of tech resources now for beginners, students, and/or people who just want to make things work without spending a lot of time coding, soldering, and troubleshooting. The Micro:bit and all the add-on boards that have popped up around it, are a great example of this.
For this project, I used two Micro:bits and two different add-on boards. I will talk about some of the differences between them later. I could have just used one add-on and one Micro:bit, and not have the remote control with the potentiometers, but my objective was to simulate how people control animatronics from afar, even if mine is a small cardboard version.
All the materials are reusable, but removing the servos is very destructive.
2 Micro servos (if you are going to be needing the motors to do a lot of lifting/moving, I recommend metal geared ones. I used regular ones and I am concerned about the jaw).
2 4 AA Battery packs with switch and the batteries
1 Standard Servo (In my experience the Hitec HS-311 works well and comes with lots of horns and screws)
1 Grove Slide Potentiometer (or similar)
2 Rotary Potentiometers (I have some caps on mine, but they are not absolutely necessary)
1 Grove Button (or similar)
1 Big diffused white LED (10mm)
A lot of recycled cardboard from boxes. Make sure the pieces are the same thickness.
Box for the remote. Big enough to accommodate Makerbit with a Micro:bit attached.
One thin nail that can go through ping pong ball.
Watercolor paints (I used tubed M. Graham) and brushes.
Ink pen/marker (I used this one)
Translucent material of some kind. (In my case I reused a packaging foam sheet. You could also used layered tissue paper.)
If laser cutting, access to a scanner makes life easier.
Step 1: Planning the Project
As mentioned before, I was inspired by The Dark Crystal: Age of Resistance. Usually, my robotics projects start with one specific movement or look that I want to achieve. In this case, everything was centered around the eye and my wanting to have it move creepily, then having the mouth move as if it were talking (having someone control it who can make voices would be a plus).
I first made a quick prototype to make sure the movements I wanted to achieve were going to work. The eye is made out of the ping pong ball and it is attached to a Micro servo that is attached to the face in the front and a base in the back. The jaw is attached to the base through a hole and placed behind the face.
After that, I made several studies of the character I wanted to create, in this case, the Skeksis Scientist, SkekTek.
Step 2: Painting/Design
With the prototype in hand and the studies of what the character looks like (plus lots of screenshots), I had to decide what to make move.
With the Hummingbirdbit board, I can control 4 different servos. I thought about making the arms move but decided against it because the cardboard would make the movements look very stiff compared to the flowing fabric of the original puppet. So I decided to make all the movement around the head: one servo for the eye, one for the jaw, and one for the head. I also chose to have him hold the Gelfling essence that would then light up.
Knowing everything was based on the movement of the eye, the scale of the face was measured with how big the head would have to be to hide the micro servo that controls the ping pong ball completely and have that be a good size eye.
I made separate paintings for the top of the head and the jaw taking to account that part of the jaw has to be behind the top of the head to hide the micro servo that will be moving the jaw and make it pivot from a point where the jaw movement can feel natural.
Once I had the face painted, I carefully cut it with scissors then used them as a guide to freehand the rest of the body.
Please note I freehanded all the drawings, but there are lots of things you can do instead if drawing is not your thing, like using a projector to trace an image unto the paper, just keep in mind the size of the servo and the eye. Also, I chose watercolor and ink to make the paintings because they made me think of the character design images that Brian Froud makes. But if you feel more comfortable with other mediums, have at it.
For the body, I knew I wanted to have a 3D effect on the robot, while still have it be mainly a painting that moves. For that effect, I knew I wanted everything to be separated into parts to make it have layers. I made the arms longer than they would be needed for the body, so they could be sticking out at an angle. I ended up with the following list of paintings: head, jaw, main body, carapace looking thing, left forearm, left arm, right forearm, right arm, right hand with the bottle.
I cut all those again with scissors very carefully. The hand was especially challenging since I knew I wanted the bottle to just be the outline because later I would add a translucent paper to make the glow of the bottle.
Step 3: Cutting the Cardboard
If you are lucky to have access to a laser cutter, then cutting the cardboard bases for the paintings will be easy and quick. If you don’t, it’s still doable, it’ll just take more time and careful cutting. You also might end up having to find a different solution for the hand, since cutting all the layers evenly will be too hard.
The pieces I needed were: Two layers for the body, one with the carapace on, to make it extra sturdy. One layer each for all the arm pieces and the jaw. For the hand, I ended up sandwiching 6 layers because I wanted to make a sort of enclosure to make the glow to be visible but subtle. Then two and a half (I'll explain why the half later) pieces for the head. Please note the eye sockets were made bigger than the eye hole of the painting to allow for free movement of the ping pong ball.
I had the advantage of having a friend with a Glowforge, so this was my process:
Prepping the SVG files.
I scanned to my computer each painted part separately, full scale 300 dpi with a completely white background.
The advantage of scanning vs taking photos is that the files end up being the exact dimensions you want. If you take photos, you are going to have to measure the "real" dimensions of the painting and resize the photo to the correct size.
In the case of the body, which was bigger than the scanner bed, I scanned it several times rotating the piece to make sure every bit of it was scanned at least once. In Adobe Photoshop I then used Automate>Photomerge command to splice all the pieces together.
With all the files ready, in Photoshop I made the files into silhouettes by pumping up the Levels, then with the magic wand selecting the white parts and deleting them, reversing the selection and filling it with black. At this point, you should have the completely black silhouettes with a checkered background. Save those files as PNG.
Open them into Illustrator, to make them into SVG files. You will click on Image Trace, then Expand, then with the white arrow select the white parts and delete them. You can Save As SVG and that file can be used for laser cutting.
Please note that since I used a Glowforge and knew the size of the bed was smaller than the body, I cut both body files in half in different directions so that they could be cut and then glued back together.
Step 4: Putting It Together Pt1
Now that I have the paintings and the cardboard bases it is time to glue them. I used a spray-on glue for this, but I cannot recommend the brand it since I had trouble later with the pieces coming off. It worked great with the cardboard on cardboard, but not with the watercolor paper on cardboard. I am sure there are lots out there that are better than the one I used. If you want to try this, find one that says it is permanent.
With the hand, I did my layer sandwich. The most detailed piece is glued to the painting and then to a piece or pieces of translucent material, then several layers of the ones without details, with the one with the hole for the forearm between them. The last layer is the one that is solid. You need to make the hole for the LED before gluing this one. I tried to have the LED be behind the details of the bottle, so it would not have a spotlight effect.
Once the paintings and the cardboard pieces are glued together, it’s time to build the robot.
I made a stand for the body and the left arm, which is the arm that goes in front of the body, by adding cardboard that intersected the body and then folded to add a platform into which to glue the arm at an angle. Then I added a triangular piece to glue the forearm in front of the arm.
I knew I did not want the right arm, the one that goes behind the body, to be permanently attached for easier transportation, so I made a stand for the right arm and forearm (now with the hand attached) after measuring the angles to make the look work as good as possible.
Step 5: Putting It Together Pt2
Once I have the body and the arms standing, it is time for the trickiest part which is the head and the electronics.
First I prep the eye. To paint the eye directly onto the ping pong ball is tricky. I made 3 different versions to see which one I liked. The one in the photos was not the one I used at the end. I used acrylic markers and a sharpie to paint it.
Next up is cutting a servo horn's arms so only the nubs and the bit in the middle are left. Then I put a skinny nail through the ping pong ball. These small balls have holes already, so this is very easy. I hot glue the eye to the nail and the nail to the horn, then attach the horn to the servo. I try to make sure that I get the servo to its furthest position so I can plan how the eye looking to the side will look.
It's time to deal with the head. First, check with the cardboard head base where it might be a good placement for the head on the neck and I make note of that.
I paint black all the pieces of the head that don't have the watercolor painting on them. Then prepare the face in two parts:
Part one is hot glueing the servo with the eye I prepped onto the cardboard base with the painting, lining it up with the eye hole careful to make it look good.
Part two glue the half face onto the base of the head. Then cut a hole on the base of the head to get the 2nd micro servo to go through it except for the thicker mounting part. You can do this by tracing the outline of the servo and then cutting it. The servo should be nice and tight and not go all the way through. Glue a servo horn unto the back of the jaw, trying to line it up so when the horn is put in the servo, the jaw will look ok.
At this point, the jaw is not attached to the servo and the servo is on the base, but not glued.
Step 6: Putting It Together Pt3
Now it is time to attach the standard servo to the body in a way that will make the head movement look ok and hide the servo. You have to make a hole unto the neck as it is drawn on the body by again tracing the servo and making a hole to get it through except for the wider mounting part. Once you have the servo through, and it all looks ok, you can hot glue it in place.
I had a nice big red servo horn that seems more durable than the other ones. I used that to attach the head by gluing it to the back of the base of the head AND screwing it in place once I check how far the movement of the head will be by carefully moving the servo gears.
When the base is in place attached to the body by the servo, now I hot glue the micro servo that will control the jaw where it was, then attach the jaw with the horn that had been hot glued and I add a screw to hold it in place as well.
The last part of the construction is to attach the top of the face that has the eye and the servo to the base of the head that now has the jaw. I added bits of cardboard that are as thick as the micro servo by the beak so as to make the face sturdier. Once I have that, I hot glue everything together very careful about the alignment.
Step 7: Dealing With the Electronics
As I have been placing the servos, I have been thinking of how the wires will look and if I can hide them well enough. Since the Hummingbirdbit board will be behind the Skeksis, I have to add the servo extension cords to the two micro servos so the wires can reach. I wired the Jaw onto Servo 1, the eye onto Servo 2, and the head onto Servo 3.
The LED is wired unto LED 3. I used jumper wires so I would not have to solder.
The remote control was built onto a box where I was able to mount all the potentiometers nice and tight, with just twist ties or screwing them in.
The HummingbirdBit is wonderful for connecting motors and LEDs. It is the board of choice for most of what I make because it is so user-friendly. They have an iPad app that can connect to the Micro:bit wirelessly and it makes troubleshooting very easy. I actually switched between a Micro:bit that was programmed to work on the iPad and the one programmed with Makecode that was to be controlled by the other Micro:bit a lot because with the iPad I could test the range of movement of the servos very easily to find what degrees I wanted to be the min and max movement for each one.
The MakerBit on the other hand, is excellent for connecting different things like sensors, potentiometers, and things that come from other kits, like the Grove parts I used. I was able to connect the rotary potentiometers with just the jumper wires with no soldering at all.
The Rotary Pot that controls the eye is connected to A2.
The Rotary Pot that controls the head is connected to A4.
The Button is connected to A3.
The Slide Pot that controls the jaw is connected to the Grove connector A1/A0.
Step 8: Coding
I did the coding on MakeCode, which is the Microsoft block coding for the Micro:bit.
The first step was to find the min and max numbers for the angles of the servos. I actually did that, as I said before, by trial and error on the Birdblox app for the iPad because it is easier and faster.
Having that, I coded the remote first. Here is the code. It maps the min and max of the pots to the min and max angles that I found worked for each servo.
Step 9: Conclusion
Now we have the robot and it is coded! Time to test it out.
Hopefully, this instructable will inspire you to make your own robot and it answered some questions you might've had.
Runner Up in the