Animate Your Skeleton's Head for Halloween

Make your boring store bought skeleton come to life! This instructable describes adding jaw motion to your skeleton to add some realism to your Halloween display.

Skills Required

This project requires cutting, soldering, and lots of maneuvering, as well as the willingness to disassemble your plastic skeleton and put it back together again

1. Plastic or resin skeleton. Mine is a 10 year old plastic one
2. Motor. I used a 3 volt mini micro N20 from Amazon
3. Two 1-inch or longer wood or metal #6 screws, plus two washers that fit
4. Large and small paperclip
5. Toggle style nylon picture hanger - you won't need the screw. Available from Home Depot
6. Old USB A cable (you will be cutting off the end)
7. USB A power supply. I used an old Apple 5 watt one, but here is one from Samsung on Amazon
8. Something to use as a bracket on your motor. I used a leftover nylon wall hanger
9. Heat shrink tubing
10. Electrical tape

You will need some tools for this project. These are what I used for mine:

1. Phillips screwdriver, for taking the skeleton apart
2. Soldering iron
3. Heat gun
4. Jewelry pliers, available from Michaels stores
5. Hemostats, for tight spots
6. Finger drill, also available from Michaels stores
7. A good Exacto knife, with a sharp blade
8. Wire strippers
9. Heat Gun
10. Patience. Sometimes materials don't behave how they should

These little N20 motors typically come with a connector, which you must cut off. Strip the wires, and tin the ends with solder. Grab a small 1.5 volt battery and test to make sure the shaft turns. . Simply shove the shaft into the screw hole of the nylon hanger. Adhere the nylon hanger to the shaft with super glue if it slips.

Grab your screwdriver and remove the two screws holding the head in place. Remove the head.

Cut off the end of a large paperclip to form a half loop. Straighten one end of a smaller paperclip

Using the half loop you just made in the previous step, use your soldering iron and hemostats or tools of your choice to heat the loop until it melts into the jaw of the skull, preferably near the middle of the jaw. My skeleton required a surprising amount of heat before the loop melted into the plastic.

Using your jewelry pliers, bend a loop in the end of the smaller paperclip and slip it over the loop in the jaw. Use needle nose pliers to close the loop of the smaller paperclip so it holds the jaw loop loosely. Go ahead and play with the pushrod, opening and closing the jaw until you get a good idea of how it all goes together.

Use your Exacto knife to cut a (fairly large) slot in the bottom of the skull to accommodate the motor linkage. I ended up cutting a half inch wide, 1.5 inch slot. It must clear the entire linkage or the motor may hang when it rotates.

I really like these plastic skeletons because they can be drilled and hold screws really well. Position your motor so the linkage lines up properly in the slot you just cut. Use your finger drill to start a hole on either side of the motor, while holding it in place. Screw in your 1 inch wood screws, each with a washer.

This next part is tricky: Solder the two washers together so they securely hold the motor in place.

I don't have a photo for this part. After you are done playing with the jaw opening and closing using the smaller paperclip as a push rod, figure out a reasonable length that will open and close the jaw without lashing as the motor turns. This is the part requiring patience. Once you have the length worked out, bend the paperclip to engage the motor linkage (the nylon hanger). Use your finger drill to make a hole through the nylon hanger then insert the paperclip pushrod into it. Use pliers to put a bend on the paperclip so it does not slip off the motor linkage.

It's helpful to try out the motor/jaw linkages by powering up the motor (I just used a battery) in order to make sure the action is smooth and doesn't get hung up. When that's complete, you're ready to move on to the last steps.

Cut off the end of the USB A cable and strip and tin the wires. Run them through the skull alongside whatever previous wiring you have in there (mine has Adafruit M4SK monster eyes.

Attach the wires. There is no polarity, so either wire works fine. Be sure to slide on your pieces of heat shrink first, then solder, slide the tubing over the joints, and shrink them with your heat gun.

As you can see from the photo, you may have to attach the screws to the skull by placing your screwdriver in the rib cage. Run your wires out the back of the skull (I have previously cut a slot for them).

Go ahead; plug in the USB cable you attached to the skull, and let's see how it looks. The new monster eyes just add to the moving jaw effect!