Building Your First WOW!! Symbian Application

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Building Your First WOW!!
Symbian Application
Piotr Madej, Comarch

Comarch
 Comarch was established in 1993 and is the
largest indepentent SW House and IT product
vendor in Poland today, with market
capitalization of 250M€ and 3500+ employees,
quated on the Warsaw Stock Exchange since
1999, with very strong links to technical
universities around Western Europe, developing
products and rendering services for
 Telecommunications
 Banking & Finance
 Industry & Utilities
 Trade
 Public Sector
 Small & Medium Enterprises
 Comarch sells proprietary products, solutions
and services on the global market, including
Europe, Americas and APAC, having customers
on 4 continents in more than 20 countries.
Comarch Group Employment

mOTiVaTIon
• Develop team’s competences
• Present the embedded know-how of the Department
• Create a nice demo set
• HAVE FUN

 To create a mobile, wireless robot
capable of drawing an input vector
graphic with color markers on a
paper sheet, controlled by a
Symbian OS-based mobile phone
and Bluetooth for data interchange
Project Goal

Project Setup
 Comarch Summer Internships 2010
 Scrum in use
 3 months timeframe (01.07 – 30.09.2010)
 Symbian-based smartphone
 Base material to be used:

Project Team
 Scrum of 3 (including 1 SM) + 1 (PO)
 4 pigs + 1 chicken (me = sponsor)
 Effort: 10 man-months total
100%
30%
3%

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Project Resources
Lego Mindstorms NXT 2.0
(8547-1, 619p)
Lego Technic Crane Truck
(8258-1, 1877p)
Lego City Tractor
(7634-1, 78p)

 Lego brick sets 408.00 EUR
 Markers ~ 5.00 EUR
 Flipchart paper ~ 3.00 EUR
 Charger and batteries 18.00 EUR
 Nokia 5800 XpressMusic 230.00 EUR
 Bluetooth Dongle 8.00 EUR
Total 672.00 EUR
Project Budget

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What can one afford with:
 10 man-months of work
 3 genius engineers
 672 EUR
?

Frida in numbers
 1126 bricks
 38 gears
 4 worm gears
 3 servo motors
 2 micro switches
 2 wheels
 1 ultrasound sensor
 1 color sensor
 1 LEGO NXT brick
 6330 lines of Symbian code (508kB)
 1360 lines of NXC code (37kB)
 6 AA batteries
 2 marker colors

Risks
 It may turn out to be challenging to develop a feasible mechanical
design to be mechanically stable, minimizing unwanted friction and
providing maximum control over motored wheels
 The robot might be mechanically unstable, it may perform
unexpected motor movements or micro-movements. This includes
leeways, shakes of the mechanism and inaccuracy of the
mathematical physics model related to the shape of wheels and
friction
 The NXT direct commands, which can be sent to the microcontroller
to control the motors, are architecturally inaccurate, eg. have only
100 possible ratios between motor speeds. Similar limitations exist
for the angle for which to turn the motor, etc. It creates a systematic
uncertainty, which has to be taken into account when calculating
movements
 Basic version of the Qt framework does not support the Bluetooth
interface. Communications code will likely have to be written in low-
level platform-specific code. It is likely that Bluetooth code written for
Symbian won't work in the simulated PC environment, and vice versa

Frida capabilities
 Manual drive (O)
 Automatic drive (SVG based) (M)
 load file (M)
 hand-drafting (O)
 photo tracing (O)

Instruction? Of course!
Rendered with
 Lego Digital Designer
v3.1.3
(http://ldd.lego.com)
 Brick Library
v114.5

Pen changer schematic  Meshing gears
 Rack and pinion
 Clutch
 Worm drives

Moving
 3 movement orders
 moveForward
 moveArc
 rotate
 Standard movement frame
includes only number of
motors' ticks

Servo regulator
 Goal: to control both servo
motor hubs' position fast,
precisely, synchronously and
without over-regulation
 Solution: Quasilinear regulator
instead of built-in PID regulator
 Theory: both motors are going
with constant speed, but...
phasing introduced
 Accelerating with preset
minimal speed (not enough
power to start, when stopped)
and taking battery level into
account

Servo regulator
 Breaking strategies:
 linear
 quadratic
 instant
 hardware (no sync)
 Goal of braking: not just
to stop, but stop
precisely in target
 Fully configurable

Interpolation
 The route is represented
by a series of lines and
circular arcs
 lines
 elipses
 elliptical arcs
 Bézier curves

Other issues
 Drawing path optimisation
 Leeway of the servos
 Wheels
 Auto calibration

Bitmap filtering and vectorizing
Modified Canny edge detection algorithm
 Scaling
 not to many segments
 not to take to much time to process
 Gaussian filtering
 remove fluctuations

 Gradients computing
 edge detection by gradient mask
[ 1 2 1] [1 0 -1]
[ 0 0 0] and [2 0 -2]
[-1 -2 -1] [1 0 -1]
 Non-maximum suppression
 clearing all pixels that are not extremal in
their local neighbourhood
 edges are thinner and more clear rather
than but thick and blurred

 Blurring
 merging both sides of a line to be one
 further removal of deviations
 Double threshold binarization
 determine which pixels are finally the edge
ones
 double values (upper and lower thresholds)
are used

 Final touch-up
 modified erosion (to make lines
thinner)
 inverting
Bitmap filtering is fully configurable

 Vectorizing
 labelling
 tracing
 merging (closing, merging torn lines, joining)
 erasing

Building Your First WOW!! Symbian Application

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