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ODROID
Turn your ODROID into a:
I/O Shield access • Install and learn the basics of Rebol now!
Year One
Issue #2
Feb 2014
Magazine
GIANT
TABLET
And create
the ultimate
Android
experience!
High Performance
computing at home
Creation and fine granular control
Using Java mutithreading
• Meet an Odroidian
Mauro Ribeiro, Senior Software engineer
• Linux Gaming - emulators
• The art of multi boxing
• 811.02ac router with odroid XU
Get up to 433mbit/sec
• Estimating Radio net interference:
• Start programming right away!
• USB Gadget drivers
Dominate your device ports to do everything
EDITORIAL
A
service to the world-wide ODROID and Open Source communities, Hard
Kernel is proud to present its newest contribution to ARM technology:
ODROID Magazine, a free monthly PDF e-zine!
This cutting-edge online publication brings you the latest ODROID news, as well
as featured articles from the expert community that has grown around the amazing
ODROID family of micro-powerhouse computers.
Intended for all levels of expertise from beginner to guru, ODROID Magazine
features definitive guides for new owners, with easy-to-follow steps in setting up your
ODROID, installing operating systems and software, and troubleshooting common
issues. For more technical users, each month will feature expert tips, hacker discus-
sions, cutting-edge projects, and technical articles to explore new ways of making
your ODROID even more versatile.
Hard Kernel’s ODROID Magazine is an ideal opportunity for our community
to come together to share and contribute articles, so that everyone can be successful
with their ODROID.
Each month, a series of article topics will be posted for consideration, and all
community members are encouraged to send submissions in exchange for monthly
rewards for those selected for publication.
The best articles are those that walk the reader through complex concepts and
procedures in a simple-to-read format. At least one picture or graphic per article is
required, and should be between 500-2000 words.
In this issue, we show you how to turn your ODROID into an enormous 42”
touchscreen Android tablet, suitable for kiosks, digital signage, gaming, accessibility,
and just plain fun. You’ve never played Fruit Ninja like this!
ODROID
Magazine
Rob Roy, Chief Editor
Bo Lechnowsky, Editor
Bruno Doiche, Art Editor
I am a computer programmer living
and working in Silicon Valley, CA,
USA, designing and building websites
such as Vevo, Hi5, Dolby Laboratories
and Hyundai. My primary languages
are jQuery, Angular JS and HTML5/
CSS3. I also develop pre-built operat-
ing systems, custom kernels and opti-
mized applications for the ODROID
platform based on Hardkernel’s official
releases, for which I have won several
Monthly Forum Awards. I own a lot of
ODROIDs, which I use for a variety of
purposes, including media center, web
server, application development work-
station, and gaming console.
I am President of Respectech, Inc., a
technology consultancy in Ukiah, CA,
USA that I founded in 2001. From my
background in electronics and com-
puter programming, I manage a team
of technologists, plus develop custom
solutions for companies ranging from
small businesses to worldwide corpora-
tions. ODROIDs are one of the weap-
ons in my arsenal for tackling these
projects. My favorite development
languages are Rebol and Red, both of
which run fabulously on ARM-based
systems like the ODROID-U2. I have
deep experience with many unique op-
erating systems.
Spent his last vacation doing nothing.
And didn’t manage to do the half of it.
ODROID Magazine, published monthly at http://magazine.odroid.com, is your source for all things ODROIDian. • Hard Kernel, Ltd. • 704 Anyang K-Center, Gwanyang, Dongan, Anyang,
Gyeonggi, South Korea, 431-815 • Makers of the ODROID family of quad-core development boards and the world’s first ARM big.LITTLE architecture based single board computer.
Join the ODROID community with members from over 135 countries, at http://forum.odroid.com, and explore the new technologies offered by Hardkernel at http://www.hardkernel.com.
ODROID MAGAZINE 3
ODROID MAGAZINE 3
CONVERTING A MONITOR TO
A GIANT ANDROID TABLET
Justin Lee and Charles Park
ouch screens are common in de-
vices such as smartphones, game
consoles, all-in-one computers and
tablets. They also play a prominent role in
the design of digital appliances such as dig-
ital signage, Point of Sale (POS) systems,
satellite navigation devices, mobile phones,
video games and some e-books.
The Android OS, one of the main
operating systems for the ODROID,
has an intuitive user interface designed
for use with a touch screen. This article
describes how to use an ODROID to
change any monitor or TV into a giant
Android tablet.
T
also more expensive, especially when
the screen size is larger than 20 inches.
A capacitive screen can only be acti-
vated with an exposed finger (no gloves
or pointers), and can experience opera-
tional difficulties if the monitor is not
correctly mounted into a metal housing
due to the electrical field. Considering
its ease of use and lower cost, the in-
frared-type touch screen is better suited
for this project.
Infrared(IR) Grid
touch screens
Infrared vs
Capacitive touch
screen
Touch screens primarily use either
infrared or capacitive technology. Ca-
pacitive touch screens are more popu-
lar for smartphones and tablets, but are
ODROID MAGAZINE 4
Principle of IR (Infrared) touch screen
An infrared touch screen uses an array
of X-Y infrared LED and photodetec-
tor pairs around the edges of the screen
to detect a disruption in the pattern of
LED beams. These LED beams cross
each other in vertical and horizontal pat-
terns, which helps the sensors pick up
the exact location of the touch. A major
benefit of the infrared system is that it
can detect essentially any input, including
a finger, gloved finger, stylus or pen. It
is generally used in outdoor applications
and point of sale systems which cannot
rely on a conductor (such as a bare fin-
ger) to activate the touch screen.
Unlike capacitive touch screens, in-
frared touch screens do not require any
patterning on the glass, which increas-
es durability and optical clarity of the
overall system. However, infrared touch
screens are sensitive to dirt and dust
that can interfere with the IR beams,
and suffer from parallax in curved sur-
faces and accidental touch notifications
MAKE YOUR GIANT ANDROID TABLET
if the user hovers his/her finger over
the screen while searching for the item
to be selected.
It’s important to check whether the
touch screen is really Windows 8 com-
patible or not. True Plug & Play de-
vices do not require
a separate driver
to be installed on a
Windows PC. If the
touch screen needs a
specific device driv-
er, it is not natively
compatible
with
Windows 8 and will
be less likely to work
with Android.
Nexio Co., Ltd. Other touch screens will
report different VID, PID and vendor
information.
Step 2: Modify
hid-ids.h and hid-
multitouch.c
After downloading the appropriate
Android kernel source from dn.odroid.
com, navigate to the kernels/drivers/hid/
directory, then add the VID and PID to
the end of the hid-ids.h header file.
Principle of IR (Infrared) Multi-touch screen
How to Choose an
Infrared touch screen
You can make your own touch screen
by following guides found on the Inter-
net, but it is not easy to implement the
complex multi-touch algorithm and well
aligned IR emitter/receiver pairs.
Before purchasing an infrared touch
screen, it’s important to evaluate its com-
patibility with Android. It must meet at
least one of the following requirements:
1) Is your touch screen listed in the Linux
multi-touch compatibility table?
http://lii-enac.fr/en/ar-
chitecture/linux-input/
multitouch-devices.html
If yes, it will be very easy to activate your
touch screen.
2) Is your touch screen Windows 8 compatible?
If yes, you need to add a few lines in the Kernel
driver and an input configuration file.
3) Does your touch screen manufacturer sup-
ply specific Android driver source code?
If yes, you need to follow their porting in-
struction.
There are 4 steps to using the touch
screen with the Android OS in a
nutshell:
1) Get the Vendor ID and Product ID from the
touch screen USB interface.
2)Modify the files hid-ids.h and hid-
multitouch.c, both located in kernel/drivers/
hid/
3) Build the kernel with the HID-MULTITOUCH
option enabled, and transfer the kernel image
to the ODROID.
4) Create an IDC (Input Device Configuration)
file.
Example PID and VID values added to
kernels/drivers/hid/hid-ids.h
Also, add the new ID in the hid-
multitouch.c source file. It must be
placed in the hid_device_id mt_devices
structure define.
Step 1: Check the
VID and PID
Plug the touch screen into any Linux
PC, then find the VID and PID by typing
lsusb
in the terminal as below right.
To determine which device entry
is associated with the touch screen, list
the devices before connecting the touch
screen, then list them again after connect-
ing it. The new entry will correspond to
the touch screen device.
During our project, when the
23-inch touch screen was con-
nected, an entry of VID:03FC,
PID:05D8 appeared in the de-
vice list, which represents a touch
screen made by Elitegroup Com-
puter Systems. With the 42-inch
touch screen connected, an entry
of VID:1870, PID:0119 appeared
to represent a touch screen from
Reading the VID and PID of the USB
touchscreen using a Linux PC
Example of adding the touch screen ID to
kernels/drivers/hid/
hid-multitouch.c
A touch screen which meets the first
requirement was not available in our lo-
cal Korean or Chinese markets. Some
touch screen manufacturers in China of-
fered to supply the driver source code
for their products, but the sample code
was not useful in the real world. The
best alternative was a touch screen that
supported Windows 8 HID-compliant
Plug & Play.
ODROID MAGAZINE 5

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