Upgrading a manual puppet to servos

[kbakonyi]

Hello!

I'm a puppet maker, and normally I like to keep my controls manual, but after working with this particular puppet for a few years I've decided I'd really like to update it to servos and something like a wii nunchuck controller to create a more comfortable user experience.
Here's a video of how my puppet performs right now: https://www.youtube.com/watch?v=rkiEavw ... Jt&index=7

Here's a video (and some photos) of a mechanism someone else created for an animatronic that I think might work for my puppet, with some modifications.
https://hackaday.io/project/16697-wheat ... e-movement

Can anyone help me out in terms of what I need to buy to start building this? I don't have access to a 3d printer so I'll need to machine everything by hand, or repurpose things.

I think I recognize https://www.adafruit.com/product/815 as one of the items used, but I don't know enough about electronics or robotics to identify anything else.

I am thinking instead of the (what I assume) is 3d printed mount in the center, I could use something like this https://www.adafruit.com/product/2464 to create a ball socket joint that the eye is anchored to.

Any and all help would be much appreciated! Thanks.

[adafruit_support_mike]

The Hackaday item is an unusual eye-movement mechanism based on flexures (halfway between pivots and springs). Designing flexures is challenging, and there's a common design that's simpler and smaller:

https://www.youtube.com/watch?v=6jqvu_M ... hallTearle
https://www.youtube.com/watch?v=I7IxOmT ... WillCogley

The Servo Controller is one piece that will be useful for building an animatronic eye mechanism, but you'll also need a microcontroller and some servos.

If you're new to programmable hardware, the Metro is the easiest board to get started with:

https://www.adafruit.com/product/50

It's based on the Arduino Uno reference design, so it's compatible with all the existing code and projects made for the Uno.

Eye mechanisms are generally lightweight, so you should be able to use standard servos:

https://www.adafruit.com/product/155

or micro-servos if you need to save space:

https://www.adafruit.com/product/169

We have a tutorial that shows how to hook the pieces together over in the Learning System:

https://learn.adafruit.com/16-channel-pwm-servo-driver

[kbakonyi]

Thanks for the reply! You mentioned that eyes are typically "small and light".... however my eye is considerably bigger and heavier than the eyes in your example videos - I'm not sure how much it weighs but it's a plastic light bulb cover, a sphere with a 6" diameter. It's thick, heavy-duty plastic.

Will these types of servos be sufficient for moving it around? How many would I need to get a natural range of eye motion (like in your example videos) and also blinking eyelids? I think that I'll need something sturdier than just pieces of wire to attach the eyeball to the servos...

Also, that tutorial you linked me to for "hooking it all up" is..... really complicated and confusing to me, but also it's showing a different board from the Metro board... Is there anything more specific available? I may need to find someone who can help me IRL...

[adafruit_support_mike]

Eye mechanisms are lightweight compared to other robotic and animatronic assemblies. Things like arm mechanisms usually need 50 to 100 foot-pounds of torque. The standard servos linked above should be fine for the puppet linked in your video.

You'll need three servos: one for up/down eye motion, one for left/right eye motion, and one for open/close motion on the eyelids.

If you aren't familiar with using servos and microcontrollers, step back and spend a few days getting familiar with the basic hardware. Our Learn Arduino series walks through the basics of connecting a microcontroller and programming it, then shows how to do several things that are frequently needed in hardware projects:

https://learn.adafruit.com/adafruit-ard ... on-1-blink

All the lessons are compatible with the Metro or Metro Mini, since those are built from the same design as the Uno itself.

As with any craft, there are basics you have to learn before you have the tools to handle more complex projects. Getting servos to move isn't terribly hard though, so you should get the feel for things after playing with the basic ideas for a few hours.