I've used one PC or another to control haunt effects, for several years. My hardware and software have both gone through several periods of evolution, and I have finally decided to put my current versions up for others to look at and put to use.
The software and hardware are fairly well documented in the files below. Take a look, and use what you feel like.


I am in the process of designing an Input board, and to make a small run of printed circuit boards.
I've posted some information about this project on the tech mailing lists.
Some details (still a work in progress) are available here.


Not so new...

Some users have located a very nice, inexpensive PC operated relay board in kit form. This can fully replace the output circuit and solid-state relays of my original design, for a great savings in work and considerable savings in cost.
This IS only an output board, however. If you only need to turn on and off various effects, without responding to inputs (PIRs, switch mats, etc.), buy and assemble the kit, use the software I have below, and you're done! If you need inputs, as most of us do, you still need to build an input circuit, as an ad-on to the kit. That is shown in Sheet4 of the schematics, below.

Here is the information on the kit:
Larger view
Kits R Us

Click on a thumbnail below, for viewable schematics!
Output Schematic Input Schematic Test Plug Schematic Input Adapter Schematic

Click on a thumbnail below, for a couple photos of my prototype:
The blue blocks are the solid state relays, for AC outputs.
Output lines are the two-pin Molex connectors along the top edge.
Sensor inputs are through the Molexes along the bottom edge.
The blue, ribbon style connector on the left edge is I/O to the PC.
AC power to the relays is through the lone Molex on the right edge.
5 Volt power to the board is through the dangling coaxial connector on
same end as the PC parallel port connector.

The bottom view shows the wire-wrap construction to the I/O connector
and the two ICs. Wiring to the SSRs and AC connectors is point-to-point
with solid wire and sleeving.
Top view Bottom view

Download files below:
C Source codeC Source code
Program documentationProgram Documentation
Default .ini fileDefault .ini file
Win32 executableWin32 executable
DOS executableDOS executable

Sample script files:
Sample file #1Sample script 1
Sample file #2Sample script 2
Sample file #3Sample script 3
Sample file #4Sample script 4
Clear-all scriptClear-all script

A .WAV player utility:
WAV PlayerWAV Player

A great source of info on PC interfacing:
From Fil's FAQ links