This programmable animated elf is the first of many moving devices to be found in Christmas Display 2016. Elmer will be joined by additional elves, Santa, and unusual toys to perform an electromechanical show.
This could be used for halloween, parties or other displays depending on the head, clothes and programming.
Step 1: Parts
I used eight servo motors for movement, three per arm, one for the neck, and one for the head.
These motors have an idler horn opposite the motor shaft and they have a rail and bracket system that facilitates mounting--available at Trossenrobotics.com.
1.5 mm hex wrench
The motors come with enough m2 nuts and bolts to perform the attachments.
3d print the torso, legs and misc. parts. This will take over 25 hours of print time.
When the servo motors arrive, be sure they are positioned at 90 degrees. Run the "dummy ninety degree" Arduino sketch (pin 2 is servo control, 5v and ground can be taken from the Arduino) so that all the motors are in the mid position.
- elf torso shldr.stl
- elf right lega.stl
- elf left leg.stl
- elf hand.stl
- elf hand washer.stl
- wire secure.stl
Attach the legs to the body. This can be accomplished using superglue gel or (my method) use a 30 watt soldering iron to melt the seams together.
Insert the neck servo cable through the hole in the back of the upper torso. Slide the motor into the center slot, shaft toward the front.
Connect a servo horn to a side bracket using four 5mm M2 screws (supplied with servo motors). You will need a 1.5 mm hex wrench to fasten the screws. With slight pressure, the screws will self thread into the plastic servo horn.
Attach idler horn to backside of head servo with silver colored screw.
Attach servo horn to head servo with black screw.
Attach C bracket to servo horn and idler horn (head servo motor) using four 5mm screws (two per horn).
Attach servo horn/side bracket (from step #4) to neck servo motor using black servo screw. I angled bracket about 20 degrees because I want the elf to be able to look behind his left shoulder at Santa. If you want your creation to have equal left and right head turn abilities, mount the bracket facing forward.
Push four M2 hex nuts into the bottom rail of the head servo. This is one of the clever features of this particular servo motor--the nuts will stay captive and make assembly less difficult.
Fasten the head to the neck using four 5mm screws.
Slide the shoulder servo motors into the shoulder slots.
Attach a C bracket to a side bracket using four 5mm M2 screws and nuts. Press four M2 nuts into the bottom of the upper right arm servo. Attach the C/side bracket combo to the bottom of the upper arm servo motor.
Attach idler horn and servo horn to upper right arm servo motor.
Attach a servo horn to a C bracket using four 5mm screws. Push this servo horn onto the right shoulder and secure with a black servo screw. I placed this at a 45 degree angle because I want the arm to be able to swing upward a lot but backward a little.
Attach upper right arm to shoulder.
Add servo horn and idler horn to lower right arm servo.
Insert elf hand through side bracket and secure with elf hand washer. Melt (or glue) the washer and the hand together.
Insert four M2 nuts in the bottom rail of the lower right arm servo. Attach the hand with four 5mm screws.
Attach the lower right arm to the upper right arm.
Secure the lower right servo wire inside the rail system using wire wrap wire (or magnet wire or fishing line).
With servo cables in slot (upper right shoulder), secure the wires with the "wire secure piece" (melt or glue).
Repeat for left arm.
Using an Arduino, wire according to this schematic and use the sketch included here to have the tiny act I provided.
Elmer's head was created by Annelle (wife) using polymer clay. The head was scanned using a MakerBot Digitizer and then a hole (to slide over the head servo C bracket) was created using TinkerCad.
Velcro tape on the inside of the head and top of the C bracket keep the head properly positioned.
The costume (sort of a hospital gown) allows the wires to escape the back. Annelle painted the elf and made the costume--quite a job to hide the mechanical stuff.
For those following the project, the wood base should look similar to the plastic prototype in Santa's Shop 2016.
More elves and more features are planned for the future :)