Fig. A: Drill the cover for the USB cable. Fig. B: Wires
and resistor connecting the USB interface and voltage
converter. Fig. C: Position the components under the
detector PCB, without making contact.
Fig. D: The wire connections to motion detector PCB
terminal blocks. Fig. E: The finished circuit with the
motion detector PCB back in place.
Configure the Software,
and Run with It
Photography by Ed Troxell (Figures A–B) and Ken Delahoussaye (Figures C–E)
The software, USB Multimedia Presenter, builds a
playlist with all the audio and video files in a specified folder. Then, each time someone comes near
the detector, it randomly selects and plays one of
them. To get started, download the application from
zip onto your PC, then unzip it, install, and launch.
In the Configure box, choose a folder on your
system containing the media files you want to
trigger; this defaults to the C:\WINDOWS\MEDIA
folder, which is ideal for testing purposes if you
don’t have a specific playlist already.
Test the software by clicking Start, with the Use
Trigger Device box unchecked below. This will
shuffle-play the files in “demo mode,” with a set
delay between each.
Now let’s put the system together. Plug the motion
detector into the computer and position it in a
direction that will detect movement. To eliminate
false-positive triggerings, you might strategically
limit its field of view. My detector picked up on
adults moving up to 15 feet away.
In USB Multimedia Presenter, check Use Trigger
Device at the bottom of the pane, then click Start.
You’re up and running. The Device Activity Indicator
should flash from green to red when motion is
detected. Approaching visitors will be amazed as
your presentation magically begins for them.
Create a Presentation
For the presentation itself, you can do anything
you want. Brightly colored graphics, flashy animations, and special effects are always effective
eye-catchers, and once you’ve got an audience,
the content must hold their interest long enough
to convey the message.
There are many other possible uses for the
system. Once, I set the detector up just outside
my front door, so that the computer would alert
me when a visitor approached. Another time, I set
it up to play a .wav audio of a shattering window.
For added effect, I turned up the volume on my
computer speakers. Whenever the trigger occurred,
it had everyone in the house running around looking
for broken glass.
Ken Delahoussaye (
firstname.lastname@example.org) is a software
consultant in Melbourne, Fla., who specializes in embedded
software and PC applications. He operates
which features access control and related resources.