working on my first three-axis skull, I followed the
conventional method and used several different software
programs. These included VSA and products from Monkey
Basic (see Resources), along with a joystick to set each
individual movement for the nod, tilt, and rotate servos.
Through my work and while observing others setting
up their routines, I found that most people didn’t really
need that kind of control. What most of us were trying to
achieve was just random movement since we really didn’t
know where the guests would be in relation to our props.
We just wanted our characters to appear lifelike.
I began trying to figure out how to program my
PICAXE for random movement of the three servos and
found that much of the work had already been done.
Joseph Maddalena — also known as Hpropman on the
Haunt Forum — had some code that would do just what I
was looking for. He made the code available and I use it
for the basis of the code I run many of my props on.
Building on the success of the EZ4, I soon decided I
needed a board that would be versatile enough to control
a variety of basic props. I wanted it to include a stereo
sound card, be able to be triggered by a PIR (passive infrared) sensor, have a three-pin servo header, have a
12V/110V relay, and be able to run a 12V motor or light.
You probably would never use all of these at the same
time, but I wanted them available. This became my simple
prop controller. It’s the board I reach for the most often
when building a prop (Figure 7).
As I became more confident in my design skills, I
decided to try my hand at building a button banger
controller. The button banger style of controller does not
require the end user to do any programming as it’s already
on the chip. Once the PICAXE chip is programmed with
the basic code, the actual routines are added by just
pushing a few buttons in the desired sequence that
triggers the appropriate relays which are connected to
your prop motors, lights, or solenoids. There are several
great controllers like this on the market, but I thought they
could be made better.
First, I wanted to bring my cost down and I also
September 2014 71
Download cable from RobotShop
Video of EZ4
EEVblog's soldering tutorial part 1
Video of the complete parrot prop
Parallax PIR sensor
08 prototyping boards from RobotShop
Eagle PCB development software
Brookshire Virtual Show Animation (VSA) software
Monkey Basic Trackskull software
FIGURE 6. Under
the hood of my
FIGURE 7. The simple prop controller — my most used board.