props? Of course not, but for the price they are a bargain! I
would spend a lot more if I submitted this myself to be
printed. As an added time saving bonus, all the design work
has been done for me. These units can easily find a suitable
place in anyone’s display.
You do need to add your own servos in order to
complete the assembly. Micro servos fit the bill nicely for
this application, with my choice being a pair of Hitec HS-53s
from ServoCity (see Resources). These come with a
reasonable price tag of only $8.49 each, while still
delivering 26. 53 oz-in of torque at 6V.
You will need to come up with an arrangement to
mount the servos. My plan is to use one of my favorite
build compounds — ProPoxy 20 (see Resources) — to
fashion some mounting platforms. You can temporarily add
some Vaseline to your servo to keep it from sticking to the
ProPoxy while you form the structure that you will
eventually attach the servo to. This allows you to remove or
replace the servo if necessary.
Drilling and tapping the ProPoxy works well and
provides a firm mounting option. I will place the eye
movement servo on top of the base plate and the eyelid
servo underneath. This will give me an all-in-one package
that can then be inserted into the head of a character. You
may choose to mount your servos separately from the eye
mechanism if that better suits your design requirements.
If you are as intrigued with this process as I am and
would like to learn even more about the amazing
possibilities of using 3D printing, I suggest you check out
David Covarrubias’ video. It takes you step by step through
the design and assembly process for a complete set of
animatronic eyes with eyelids (see Resources). It can be
purchased through the Stan Winston School of Character
Arts and is well worth the investment.
This has been out for a while, so the software and
some of the parts will have changed, but it is still a great
resource. I had no previous experience using a CAD
program and it was a fantastic introduction.
While you are on the Stan Winston site, make sure to
peruse the entire lineup of how-to videos they have
available. They cover a wide range of subjects including
sculpting, molding, makeup, electronics, and much more.
The Complete Mechanical
This fully assembled model from Monster Guts looks to
be a great answer for anyone who is interested in a plug-and-play solution (see Resources). Although I have not had
the opportunity to put these to the test, they look like a
fantastic product. The experiences I have had with their
other offerings has been extremely positive and I see no
reason why this product would be any different.
The video link on their page shows it in action and it
exhibits a wide range of motion. You are able to add
internally lighted eyes and select from three choices of
colors. They also offer a dimmer option for the eyes which
allows you to select and manipulate their operation.
This product is designed to work with their three-axis
skull kit, and easily attaches to that plate using two predrilled holes. Using the combination of three-axis head
movement and two-axis eyes provides the opportunity to
add a considerable variety of realistic movement to your
The Eyes Have It!
All of the mechanical designs we have covered so far
require you to add your own electronics to control the servo
movements to bring your eyes to life. I utilize a simple
PICAXE 08M2 driven board (Figure 8) with some random
movement code. Of course, you can use your
microcontroller of choice and add your own code, but the
PICAXE does the job for me. (My code listing is available at
the article link.)
As with the programming for my three-axis heads, I
find that a random movement code is sufficient for my
purposes. I do not have any need for the eyes to be looking
in a specific direction at a specified time, so there is no
need for me to program each individual movement.
Programming time saved here can be put to good use
SERVO 04.2016 43
Figure 7. A simple yet very effective design.
Figure 8. A small PICAXE board runs my eyes.