provides the TCP/IP stack. In addition to these two devices,
you will need to run some web code on a local machine. I
happened to use another NetBurner device, but any web
server (including your PC) can work for this.
Using a Web Server
It is possible to use the MOD5270 built-in web server.
However, I did not go this route as it requires an expensive
static IP address for your mobile connection. A static IP
address has a few downfalls, as well. If your device does
not currently have a mobile connection, then the web page
would not exist, and the end user would get a 404
“website not found” error. With a local web server, the
application can always state the last known position of your
The web server interface uses the Google API to
provide a familiar Google Maps’ style interface. Google has
provided a great API for creating simple GPS applications.
With the Google API, the application’s webpage is able to
plot the robot’s location anywhere in the world with both
satellite imagery and easy to read maps. If your bot is near
lo n gitu de
a photographed street location, then it also provides a
panoramic eye-level view of the area.
Setting Up the Hardware
Hardware configuration is not too difficult. The biggest
challenge is finding the 3.8V required by the Telit chip. In
my setup, I had 5V and 3.3V power available. The
schematic illustrates how I obtained 3.8V from the 5V
source. The MOD5270 requires 3.3V. With 3.3V power
already available, no voltage level translation is required.
The two devices require four lines for serial
communication. Two of the lines will be reading the GPS
values while the other line will be controlling the GPRS
Finally, you will need a way to toggle the Telit chip on
and off. The on/off switch on the Telit device works exactly
like a power button on a cell phone. It is a simple toggle
that must be held for at least one second. Once held, the
power will toggle either on or off. In the case of the Telit
chip, you must pull the on/off switch down for at least one
second to toggle the power.
This schematic shows the
TELIT GM862 connected to the
NetBurner MOD5270 module.
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