Choosing A Haunt Controller

It's Personal

I have been working with computers for over 30 years. Friends and relatives sometimes ask me, "What kind of computer should I buy?" My answer is always "It depends on what you want to do with it." Sometimes I see folks salivating over fancy new computers, bemoaning their old obsolete machines. I say "A computer isn't obsolete as long as it can do what you want it to do."

The above conversations usually take place in the context of larger, desktop computer systems. But the same criteria should be applied in evaluating smaller computers dedicated to animating and automating your haunt.

We will consider numerous issues that go into the decision, but the machine must meet your requirements. It's a very personal decision.

What Is Available

In my introduction to controllers, I break controllers down into several categories.

cost of tools cost of product skill/effort

type example HW dev SW dev each unit electronics programming

Bare CPU highest low low highest highest

Bare MCU high low lowest high high

Augmented MCU BASIC Stamp low low medium low medium

Single-Board Computer low medium high low low

Personal Computer low highest highest lowest lowest

		cost of tools	cost of product	skill/effort
type	example	HW dev	SW dev	each unit	electronics	programming
Bare CPU		highest	low	low	highest	highest
Bare MCU		high	low	lowest	high	high
Augmented MCU	BASIC Stamp	low	low	medium	low	medium
Single-Board Computer		low	medium	high	low	low
Personal Computer		low	highest	highest	lowest	lowest

These categories are part of a spectrum, where the trend on the low end is:

less hardware comes built into the controller
less sophisticated operating environment for programs to run in (if any)
less expensive software tools required to create programs (e.g. assembler)
but the program is harder to write
more expensive hardware tools required to develop a system (e.g. oscilloscope or logic analyzer)
after development costs, each unit is less expensive to build

The trend on the high end is:

more hardware comes built into the controller
more sophisticated operating environment for programs to run in
more expensive software tools required to create programs (e.g. MS Dev Studio)
but the program is easier to write (e.g. Visual Basic)
less expensive hardware tools required to develop a system
after development costs, each unit is more expensive to build

What kind of controller should you buy? "It depends on what you want to do with it."

Your Needs - What Can A Controller Do In Your Haunt?

So what do you need to use a controller for? Here are some possibilities...

Output

For starters, a controller can control things - by turning things on and off. If you hook a light emitting diode to a low-voltage output, you can make it blink on and off. If you hook a solenoid valve to a buffered output, you can make it puff blasts of air whenever you want. In fact, you can turn on and off anything, like our Controller-Driven Fogger.

For more information, see BASIC Stamp Output.

Input

A controller can also look at something in the outside world, reading an input value.

This could be a switch triggered by the presence of a trick-or-treater, which tells the controller to start the show.

For more information, see BASIC Stamp Input.

Sequencing

A lot of haunt control revolves around sequencing through a predetermined list of operations, like this:

wait for the Trick-or-Treater (by watching for input)
pop up the monster
after the monster pops up, make it roar
display the monster for 5 seconds
hide the monster again
do not trigger again until the current kid leaves (detected by watching for input)

Timing Measurement

A microcontroller can measure the time between two or more input.

This could be used for locking out close events, like "wait until the kid has been gone for 30 seconds before triggering again".

Timing Generation

A lot of haunt control revolves around timing. In a complex sequence, there are places where one wants to pause for a fixed time period (display the monster for 5 seconds) or until some event happens (do not trigger again until the current kid leaves).

If timing is simple enough, one might use a simple analog timing chip like a 555. There are numerous commercial haunt timers that provide functionality like this. A controller can do the same job as an analog timer chip, but with more flexibility and precision.

Reacting

Most haunt automation is very simple, and the ways that it reacts to external situations is equally simple. Example: Wait until somebody steps on the switch pad, then pop up the monster. In situations like this, no intelligent control is even necessary.

But the use of a controller opens new avenues:

You can react to random elements, like: Flip a coin and only scare this kid if it comes up heads.

The controller can take input from other sensors: Only trigger this scare if there is a large number of kids; don't trigger this scare if the kid is using a flashlight.

Here's one that you might consider to be an exercise in sequencing that extends past the boundary of a single scare. But I prefer to think if it as the controller reacting to a new input: the number of times it has been previously triggered.
- Only pop up the monster on the left for even-numbered kids.
- Only pop up the monster on the right for odd-numbered kids.
- Every third appearance of the monster on the left should be accompanied by a flash of lightning.

Switching

In some of the previous examples, the controller switched various effects on and off. But a switch can also select something.

For example, you could have two projectors focused on a rear-projection screen: one with a picture of a pretty young woman, the other a terrible beast. If the computer switches turns off the young woman and turns on the beast, the image on the screen instantly transforms. If the computer slowly dims down the woman while slowly brightening the beast, there is a gradual transformation.

Playback

A standard desktop computer can easily play back a file containing a movie or a sound. Low-end controllers like a PROP-1 do not have the processing power to directly replay sounds or video.

But even a simple controller can trigger a recorded sound chip or CD player to play back sounds.

Effects Generation

If a controller has enough computing power, it can generate effects in real time, like dynamically distorting a sound track, or morphing a portrait.

Your Abilities

At the time of this writing, I have been working professionally with computers for 26 years. Before that, I spent 8 years working with computers in school and as hobbies. I have programmed many different computers, using many different languages and techniques.

With such a large store of experience to draw on, there are things that I can do that would astonish some less experienced folks. By the same token, I can look at the work of those smarter and more experienced than me and ask myself, "How in the Hell did he do that?"

Your effective abilities come from:

Previous experience in related areas.
Previous experience in unrelated areas that may still be germane.
Your ability to learn new stuff.
Your willingness to do some work and thinking - and build up your abilities via study and practice.

So there are two components of ability:

What you can do now - current.
What you can do with a little time, study, and practice - capacity.

A final factor is the other resources you can bring to bear on the subject. If you have the ability to program a Cray supercomputer, but don't have access to one, the ability isn't very effective. If you are unable to master the development of complex software, you can make up for it by buying a product to make it easier.

Is A BASIC Stamp Or Prop-1 Good?

Parallax makes a line of controllers called BASIC Stamp. There are so many products in this line that it is hard to choose. They even have a department aimed at haunters, Parallax EFX, which makes a controller called the PROP-1.

It is natural to ask if these products are good.

But I hope that, after reading the rest of this page, you realize that "good" is a relative term. They are good for some things, and not so good for others.

In general,

Stamps are slow.
- This is especially true of the less expensive versions. Parallax does offer faster Stamps, but they are more expensive.
- Stamp programs are compiled ("tokenized") to a p-code form, which is then interpreted on-chip. This approach is inherently slower than programming on the "bare machine".
- Stamp programs are stored in serial EEPROM, which is slower to access than many other forms of memory.
Stamps are easy to use. Parallax has a free IDE that is easy to use.
Stamps don't have much memory.

As a result of these attributes,

With respect to using Stamps for timing, you can pick one or two of: high-speed, precision timing, or control more than one thing.
Stamps are very nice to control sequences of events, but if the list is long, you may run out of memory to hold the list of events.

One particularly strange use of a Stamp is to produce flickering candles with software. You can drive eight flickering candles with a PROP-1, and the results are pretty good. But creating eight channels of flicker pushes a PROP-1 to the limit of its capabilities - and the board is expensive and physically large for this purpose. In other words, eight flickering candles on a PROP-1 is more of a "gee whiz!" thing than practical. [Yes, we've done it. Yes, it was fun. Yes, we recommend playing with it. But a PROP-1 for flicker is overkill.]

Choosing A Haunt Controller

It's Personal

Switching

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