I posted about my progress taking my existing paper mache pumpkin from several years ago and turning him into an animatronic pumpkin. Please see the links below for more detail.

Peter the Pumpkin

Peter the Pumpkin - pt2

Peter the Pumpkin pt3

Peter the Pumpkin - pt4 (ready to Share the Scare)

 

Here is the final verdict from last night and a wrap-up of this project (until next year......).

 

Last Minute Modifications

Always a risky thing to do, but a few days before the 31st October I decided to add a microswitch to the stepper motor. This was because if the power got interrupted then the head would think that it's current position was now the starting point. It could easily result in the head being damaged as the cables would get wrapped around the spindle. The code runs at startup and powers the turntable anti-clockwise until the microswitch triggers. It then steps slowly away until the microswicth is not selected....this is now the reset baseline position for the effect to start from. At that point the eyes also flash green/red to let me know the setup has completed.

 

Did I Manage to "Share the Scare" ?

There were definitely screams, silence and then the door knocking, and a few nice comments so I think he worked quite well

Here is a video of Peter waiting outside the door for someone to drop by (scary audio is overlaid during editing):

 

Diagram

Using the Fritzing application I sketched out my circuit diagram for anyone that wishes to replicate the project.

The capacitor on the Pololu A4988 driver is a 22uF 35v electrolytic.

 

Software

A slightly tidier version of my Arduino code is available on my Github site HERE  it contains much of the code still that I used during testing.

 

Some Final Photos

{gallery} Final Photos
The circuit board minus all the peripheral leads and cabling
Running mains free using a 12v Sealed Lead Acid battery
A microswitch to reset the head to a known starting position
"Not so scary when it's daytime are you ?" - checks power is off before saying that !

 

Future Improvements

  • Get some audio working (triggered from the Arduino Uno).
  • Upgrade the stepper to a motor with better torque (and less noisy).
  • Add some randomness to the responses.
  • House the electronics in a suitable box - adding some quick release connectors for simplicity.
  • Do some dentistry work on Peter as I found his missing tooth in the Halloween box last night:

 

Last Thoughts

  • It was a fun build during which I learnt a lot about integrating the various component parts together both mechanically and in the Arduino software.
  • I've been really interested in animatronics for years but have never got around to actually making anything before.
  • I was fascinated when I got the eyes powered up for the first time - quite eerie.
  • Feel free to ask if I have omitted something you wish to know more about.
  • I hope you have enjoyed reading my build blogs