Animatronic Demon Head

I followed my first Instructable by Ikkalebob , I made his eye mechanism, and then his controller to control the mechanism physically. I was really happy with both of his projects and in the end I had an eye mechanism that I could control, which is really cool!

After a month or so of looking at it, playing with it, and thinking about what I could put the mechanism in.

I decided, why not make an animatronic demon head for halloween.

After following this instructable you will have your own animatronic demon head.

Supplies for assembling the demon head:

1. 3D Print Files
2. Microcontroller (esp32, ArduinoUno)
3. Power Supply
4. Servos
5. Servo Driver
6. M3 Bolts ( M3x6: 2 , M3x8: 12 , M3x12: 6 , M3x16: 13 )
7. Screws ( #6x3/4: 4 )
8. 20 awg Wire
9. Hand Drill
10. Metal Rod
11. 8mm Flange Coupling
12. Yarn
13. Burlap
14. Primer
15. Acrylic Paint
16. Clear Coat
17. 2"x6"x6" Wood Block

none of the links provided are affiliate links, they are the exact parts that I used for the construction of this build.

This print took me roughly 40 hours and about 1kg of PLA filiment on my Sovol SV01 printer. Once all the files start comin off the printer, do whatever post processing methods you want and then you can go through and clean the holes with the hand drill.

Be Careful:

1. If using the hand drill I listed:
2. If it gets too hot while cleaning out the holes you can melt the PLA causing the drill bit to gum up
3. It can also cause issues with hole deformation.
4. I have counter-sunk the bolt holes for most of the jaw assembly.
5. When cleaning out the bolt holes, be sure to clean them out slowly as the counter-sunk holes are bigger to accomodate the head of the bolts. The hole that actually houses the threads of the bolts are significantly smaller.

Follow Ikkalebob and his instructable to build his eye mechanism.

NOTE: When printing his files, you can skip printing his "main base" file. During assembly use the "modified-main-base" in place of "main base".

Primer all of the parts of the demon head, and let them dry completely. I chose not to paint the eye mechanism itself, nor did I paint the Jaw bracket as they will not be seen.

Once the primer is dry, let your creativity run wild!

Using acrylic paint from Walmart and some cheap paintbrushes I think it turned out pretty decent.

After the paint has dried, be sure to use a sealant coat of paint, or it's going to get scuffed pretty bad when assembling.

I used duplicolor matte clearcoat for the jaw, ears, head and eyelids, and I used duplicolor gloss clearcoat for the eyes to give them a bit of a shine.

Assemble the jaw mechanism:

1. Using the screws provided with the servo, attach the servo to the jaw-servo-bracket making sure to install with the proper orientation of the servo and wires. The wires should be facing upwards and the horn side of the servo should be as shown in the photo above.
2. Using 4 M3x8 bolts attach the jaw-servo-bracket to the jaw-servo-base.
3. Attach the single arm servo horn and rotate it towards the desk to ensure the servo is at the maximum angle. This will be the mouth closed position later and is critical for proper functionality of the entire jaw mechanism.

Assemble the neck:

1. Using 4 M3x16 bolts attach the neck-rear to the neck-bottom, using the lower four holes.

Prepare and install the eye and jaw mechanisms:

1. Using 4 M3x16 bolts, thread the bolts through the holes of the jaw-servo-bracket about 5 threads while the bracket is sitting on the table.
2. Insert the jaw-servo-bracket into the head below the center section and align the bolts with the holes.
3. Back the bolts off one at a time to get allow the jaw-servo-bracket to sit flush with the center section of the head.
4. Thread them into the jaw-servo-bracket and into the center section so they stick through the center section by a few threads.
5. Install the eye mechanism above the center section and align the holes with the bolts.
6. Tighten the bolts so the mechanisms sandwich the center section.

Install the ears:

1. Place the ears in position, be careful not to snap off the bolt hole sections, loosen the eye and jaw mechanism bolts if needed to get a flush fit.
2. Using 2 M3x12 bolts, Install 1 bolt per ear in the outter bolt hole and bolt to the center section of the head.

Attach the neck assembly:

1. Feed the jaw servo wires in between the neck-rear section and the head. I tucked the wire into the rest of the wires from the eye assembly to keep it out of the way for this part.
2. Ensure the wires are not going to get pinched when aligning the neck-rear with the center section of the head.
3. Using 2 M3x16 bolts, attach the neck-rear section through the inner ear holes and into the center section of the head.
4. Using 4 M3x8 bolts, attach the neck-bottom to the bottom of the head.

Attach the jaw:

1. Using 2 M3x16 bolts, thread the bolts from the inside of the jaw by hand so there is roughly 2mm of thread sticking through.
2. Place the jaw in the head and bolt the jaw in place loosely, there will be about 3mm of bolt in between the jaw and head, they do not sit flush with eachother. Adjust the left and right sides until the jaw sits as centered as possible, and moves freely forwards and backwards the full range of motion.
3. Attatch the single arm servo horn to the jaw-arm using the provided screw.
4. Rock the jaw all the way closed and attach the jaw-arm to the hole in the back of the jaw using a M3x16 bolt.
5. Ensure the jaw is all the way closed and connect the servo horn to the jaw servo. This can take some fiddling to get it to line up and install properly.

Attach the base:

1. Using 4 M3x8 bolts attach the 8mm flange coupling to the bottom of the neck-rear and neck-bottom section.
2. Install the 8mm metal rod into the flange coupling until it bottoms out then tighten the set screw.
3. Using 4 #6x3/4 screws, attach the 8mm flange coupling to the center of the 2"x6"x6" block of wood.
4. Install the 8mm metal rod into the flange coupling that is attached to the block of wood until it bottoms out then tighten the set screw.

If you've made it this far, I'm going to presume you have already created the eye mechanism, and therefore, all that's left to do is plug the Jaw servo into the next available pin set (#6) on the servo driver board.

I drilled two small holes to accomodate the servo driver board being mounted to the back of the eye mechanism. Align the servo driver board where it looks centered, mark the positions where the right side holes in the servo driver board should be. Carefully drill two holes and mount the servo driver board using 2 M3x6 bolts. I think it cleaned up the wiring quite well, and plan to mount the microcontroller to the neck with some standoffs using the same method.

Cut two 12" lengths of wire, I used 1 red and 1 black to indicate positive and negative. These two wires are going to be the connection wires from the external power supply to the power and ground of the servo driver board.

Strip the wires 1/8" on both ends of each wire. One end of the wire will connect to the appropriate terminals of the adaptor connector of the power supply. The other end will connect to the positive and negative of the servo driver board.

The servo driver board requires quite a bit of power to drive the servos. I chose to go with the Power Supply listed above, as it can handle 10amps of current. Before plugging the power supply into the electronics, adjust the voltage to 5 volts to prevent damaging the servo driver board.

Ensure the microcontroller has its own power supply connected via usb to pc or powered through the barrel jack.

Plug the power supply into the connector for the servo driver board.

You should see the jaw servo move the jaw to the centered position.

Load the demo program and watch the demon head come to life. Actions are performed every 1 minute, you can adjust the time in between actions in the code.

Note:

Please do not go below 30 seconds or the servos will not have enough time to reset to their home positions for the next action and can lead to damage of the servos.

All code contained herein is free to use, modify and implement how you see fit.

Making the hair was interesting for me as it's a problem that I've never had on previous projects. I think it turned out alright, and heres how I did it.

1. Cut a strip of burlap roughly 3" wide and 4" long.
2. Cut lengths of yarn roughly 6" long. (I cut mine as I went and didn't count how many)
3. Feed the yarn through the corner hole of burlap using a pick or crochet needle
4. Pull the yarn through roughly half way, and feed back through the opposite direction of the next hole.
5. Use a new piece of yarn for the next hole and repeat the previous step until you have a full strip of hair.
6. Un-twist all the hair
7. Brush with a comb and style as you would like
8. Put the hair on the top of the head, and ensure the yarn and burlap are not in contact with any of the electronic components or wires.
9. Once you have the hair in a good position on the head, you can glue it down using hot glue.

IMPORTANT! Ensure when attaching the hair to the top of the head that none of the yarn or burlap is in contact with any of the electronic components or wires. Please, be safe and don't burn your house to the ground.

Convert the entire program to run on an ESP32, do some black magic to give it a voice, and then connect it to Twitch chat to be activated by keywords typed by users in chat.

** This step will not be covered in todays tutorial