RoboPuppet

A couple weeks ago Charles sent me a link to a video from a company that makes a bunch of animatronic products. They’ve got a remote-controlled bird puppet that moves its beak and turns its head side-to-side. It sells for… NINE HUNDRED DOLLARS!? And that’s their cheapest product. I suggested that maybe, if you weren’t that interested in the wireless aspect of it, it might be possible to do something a bit cheaper. Like, oh, $800 cheaper…

My first thought was to use a nunchuk from a Nintendo Wii. It’s cheap and interfaces to an Arduino microcontroller fairly easily. I did a bit of poking around and worked out that a single Arduino can control up to 8 servo motors. I figured I could control one servo per button, and one for each joystick axis.

That would use up 4 servos, leaving 4 free. I decided to add an audio jack to see if I could drive a servo based on recorded vocals. That would use up 2 of the remaining ones; one for each audio channel.

I wired up a protoboard with connectors for a nunchuk, 8 servos, an audio input and a power supply for the servos.

…and wrote some code to read the inputs and translate them into servo data.

Here’s a test with a nunchuk driving 4 servos.

http://youtu.be/fz9VbYvajX8

To test it out in a practical situation, I built a puppet stand out of PVC pipe and strapped the electronics to it. Here’s the result.

I’m only using one servo there but you could conceivably use a bunch on a single puppet, say, to move the head side-to-side or make the eyes blink. Maybe even assign a sequence of movements to a single button press.

Oh, and the total cost of the rig shown in the video?

• Arduino – $30
• nunchuck – $15
• servo – $12
• connectors & components – $10
• PVC pipe – $10
• 9V supply – $7
• protoboard – $6
• 6V battery pack – $2

So, $92. You could even throw in another servo for moving the head and still come in just over $100. Add some felt and foam, and you could make a whole flock of birds for $900.