Animatronic Following Scarecrow and Haunt Automation

This scarecrow (let's call him Jack) senses you in different parts of the yard, wakes up and looks at you. As you get closer Jack bears his teeth and chomps. Jack pretends to be a static prop during the day and wakes up at night (just like all good ghouls). Jack is extremely creepy. Jack can turn left / right / center, head up / down / center, eyes on / off / blink / wink, and hide / show his teeth. Motion sensors placed throughout the yard are both used to set off groups of props and to cue Jack where to look. You can checkout the video in action here.

So if you want your haunt to be extra scary here is what you will need:

Scarecrow Head
- Animotion Scarecrow Mask
- 3 servos
- 2 leds
- 1 motion sensor and wire
- 1 Particle Photon Board, PCB board, headers, and a USB power cable
- 1 Project Box
- Bolts, nuts, angle brackets
- 1 11.1V Drone Lithum Polymer battery 2200mAh
- 1 12V to 6V power converter - Gartt YPG 20A HV SBE
- 1 5V rechargeable battery or a 5V power adapter
- Optional voltage readout for the 6V source.

Scarecrow Body
- Wood for frame (cheap bamboo flooring is great for projects)
- 4 wire coat hanges
- A little hay for the hands and feet
- Some zip ties
- Pants and a shirt (grab something that looks scarecrow from goodwill)
Motion Sensors (as many as you want)
- 4 Screw Mount Terminals
- 1 Particle Photon Board, PCB board, headers, and a USB power cable
- 1 Project Box
- 1 5V usb power pack or a 5V power adapter
Server
- A computer capable of running node.js. A PC, Mac, or Raspberry PI will work fine.

Step 1: Scarecrow Head

The Animotion Scarecrow mask normally bears its teeth when you lower your chin. We are going to modify the mask to:

Add a servo to control the jaw.
Add a servo to control head tilt
Add a servo to control head pan
Add two red LEDs for eyes.

First we need to modify the mask to create a platform on the upper jaw to mount the electronics. I like to use cheap bamboo flooring because it is strong, easy to work with, and thick enough to countersink screws if needed. After stripping the tongue and groove off the bamboo flooring I cut a piece the width of the mask and round the outside corners. If you carefully peel back the burlap on the mask you can drill two holes on each side for an angle bracket. Similarity you need a bracket to push against on the bottom jar. I mounted the tilt servo in the center of the platform which then attach to the pan servo. The pan servo attaches to a piece of bamboo for the neck where we can mount the batteries and electronics.

You may need to put in a counter spring to reduce the pan tilt load on the servo. I found that between that and the hat that comes with the mask it was easily balanced.

The lower jaw attaches to a servo through an adjustable length arm.

Note that most servos provide 180 degrees of motion. You want to mount the servo so the center position of the servo is at the center position of your needed motion. Don’t worry if you are a little off we will adjust limits in the software.

The eyes LEDs then get mounted on the top side of the upper bamboo sheet.

Step 2: Scarecrow Controller and Motion Sensors

The scarecrow controller uses a design I created for Halloween last year (see this article), which I modified for this effort. That article goes into great detail about how to build the boards and interface to props for automation, so I won't repeat it here. This board was designed with two transistors for controlling props through test or foot ports and two digital led outputs for other props. I added a few things to this design.

A breakout board for servos and the motion sensor.
An optional voltage meter for the servo power.

You can download the circuit diagram from github here (it is a Fritzing diagram). The breakout board is optional, but makes it easy to connect the standard 3pin servo, power, and motion sensor.

I used a 11V battery with a 6V converter to drive the servos separately from a standard 5V USB power supply for the particle controller board. Since the servos can each pull up to 1A, this battery could actually operate many more servos (20A max load).

You can download the software for the particle board here. You will need to make a few modifications to tune your servos. The halloween2017.ino file contains directions on how to tune your servos. It is very easy to modify this code and use the particle build tool to flash the particle over wifi (see the particle build website)

Four external motions sensors are more than enough (for left yard, right yard, center yard, and by scarecrow). You can also use the boards to control props on motion. This is really nice because if you have fog and lighting the props either don’t go off at all or go off too much.

Step 3: Scarecrow Body

The scarecrow body is probably one of the easiest parts of the design. I basically cut a frame from the bamboo flooring (2x16 inch, 2x24 inch, 1x 6 inch), drilled holes, and bolted the parts together.

For the clothes I purchased used clothes from GoodWill (something that looks scarecrow like). Next I drilled holes to attach a coat hanger for each leg and arm. This allows you to create some realistic poses for the body. Simply stuff with whatever you have (we used old towels).

The frame sits against your chair and give the moving head a sturdy base. Finish off the outfit with a piece of burlap cut to put around the need. For the hands and feet I zip tied some hay and hooked the end of the coat hanger to the zip ties. Then I zip tied the end of the pants and end of the shirt to hold it in place.

Step 4: Running the Server

You can download the server code here. The file contains instructions about what to modify for your particular boards, props, and motion sensors.

You need to put in your particle token.
You need to put in your devices and device ids
Enumerate your props
Write your motion callbacks
Enumerate your motion sensors

You can run this on any device that can support node (including a raspberry pi) as follows:

node halloween2027server.js

The output will tell you what sensors went off and what props were triggered. The cool thing about the server is you can turn the whole yard off just by stopping the server and have it come to life at night.

Get creative with this you can really do some amazing haunt automations and scarecrow that follows people through the yard and bears it teeth when you get close is super creepy.