PI ZERO

Projects
SHOWCASE
>STEP-04
3D printing
The 3D print of the 150×150mm primary
model was completed on a PrintrBot
Metal Simple printer, using Microsoft
3D Builder, in just over 26.5 hours. The
interior scaffolding was then removed
manually to hollow it out.
>STEP-05
Mounting the Pi
To enable easy removal of the Raspberry
Pi from the model, it was mounted to the
square base via the latter’s four bosses,
which accommodated McMaster-Carr
press-fit threaded inserts to take the M2.5
Pi mounting screws.
>STEP-06
Wiring up
All LED wiring to the Pi’s GPIO pins was via
a single 40-pin socket, using a pre-made
ribbon cable with one end cut off, and the
relevant GPIO pin lines soldered to power
and ground hook-up wires for the LEDs,
along with resistors.
camps (in fixed locations) and the
summit, plus the start and end
locations, so that trip has nine
associated waypoints, seven of
which are on my 3D model. All of
the data is stored in a SQL Server
database which also supports
remote debugging/deployment was
super easy to set up and use.”
Based largely on Microsoft’s
Blinky example code
(magpi.cc/1ndOkcN), Kurt’s
program calls the RainOn Azure
service API every ten minutes to
The system worked in real-time
and the waypoint LEDs stay lit
after I had reached that location
Above The 3D printed model with scaffolding removed
Below A breadboard prototype was used to test the system
spatial data, so geofence tests and
other geospatial calculations are
super easy.”
Coding the Pi
When it came to programming
the Raspberry Pi to process the
location data, Kurt ended up using
the Windows 10 IoT Core operating
system. As a senior partner
engagement manager in his day
job at Microsoft, Kurt was already
well versed in Windows and its
Visual Studio developer tools. Even
so, he tells us he also developed a
Python version of the code under
Raspbian, but found the Windows
10 IoT Core / Visual Studio route
much easier. “Three things
were very attractive about using
Windows 10 IoT Core: 1) Visual
Studio is awesome (and familiar),
2) I could develop in C#, and 3) the
obtain JSON location data. If this
is within a geofence, set at a 200m
radius, for one of the camps or
the summit, the corresponding
LED is lit.
Testing it out
To check everything was working
properly before leaving for
Tanzania, Kurt used the Postman
test tool to call on his RainOn
APIs and simulate data from the
personal locator device. “I also
use Google Earth quite a bit to find
the lat/long of various places and
measure distances. So I tested
the system by sending simulated
locations near the waypoints.
When I first developed the
geofence/waypoint feature, I did
actually use local locations and
drive around in my car with the
device to test it.”
34 February 2016
raspberrypi.org/magpi