Alcorn Mcbride AM-4, Hardware And Software Reference Manual

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GPS Operation 53
The AM-4 Digital Audio Machine can automatically trigger MP3 sounds whenever it
enters into a predetermined geographical area. With this feature you can easily
design a “No Operator-Intervention Required” audio system on a tour bus or tram
that automatically plays pre-recorded spiels or sounds whenever it arrives or passes
by a specified location.
Enable the GPS mode of
operation by turning
DIP switch #4 ON
(down).
In GPS Mode, the AM-4
will not accept normal
serial commands.
The AM-4 accomplishes this by reading a data stream from a GPS (Geographical
Position Satellite) sensor. This sensor is often in the form of a “GPS Mouse” or pod
that outputs a serial data stream containing Longitude and Latitude data obtained
from orbiting GPS satellites, and normally connects up to a serial or USB port on a
laptop computer running mapping or direction-finding software. In the case of the
AM-4, the sensor connects up the 9-pin serial port.
The AM-4 accepts a
standard NMEA-0183
data stream at default
4800 baud. You can
change the baud rate
using the BR command
in your GPS playlist.
The Longitude and Latitude data supplied by the GPS sensor is compared to
geographical points stored in a playlist. The playlist used for GPS operation is a
normal playlist (described in the
Playlist Files section of this manual) except the
Longitude and Latitude commands it contains are continuously compared to the
incoming GPS data. As each coordinate, or waypoint, in the playlist is matched the
AM-4 responds by executing the next line of the playlist. While the AM-4 is waiting
for a coordinate match, the playlist can command the unit to either play a background
track, or it can just wait silent. It all depends on how you make the playlist.
For the latest version of
GPS Builder go to
http://www.alcorn.com/
support/software.html.
The playlist used for GPS operation is easily created by a Windows application
called “GPS Builder” supplied by Alcorn McBride.
GPS Builder
GPS Builder provides you with a simple method of creating playlists for use in the
AM-4 while operating in GPS Mode. Here are some of the main features of GPS
Builder:
• Accepts and automatically detects any NMEA 0183 GPS input source.
•
Allows you to quickly enter Longitude and Latitude waypoints along a route
with the click of a button (or spacebar).
• Contains a complete list of built-in commands for the AM-4. You do not
need to enter them manually.
• Enables you to easily edit playlist parameters.
Below is a screenshot of the GPS Builder program with a playlist loaded: