Arexx YETI User manual

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YETI
©AREXX - THE NETHERLANDS V01082006
Manual: Model YT-3000
Walking robot

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NOTICE!
YETI ROBOT KIT is a trademarks of AREXX, The Netherlands and JAMA, Taiwan.
AREXX and JAMA are registered trademarks
All rights reserved.
Reprinting any of this instruction manual without our permission is prohibited.
The specifications, form, and contents of this product are subject to change without prior notice.
We are not liable for disadvantage or damage caused by improper use or assembly.
Technical support:
WWW.AREXX.COM
WWW.ROBOTERNETZ.DE
Manufacturer:
AREXX Engineering
JAMA Oriental
European Importer:
AREXX Engineering
ZWOLLE, HOLLAND
© Arexx Holland en JAMA Taiwan
1. Produkt description YETI 3
2. YETI general information 4
3. Who or what is YETI? 11
4. Hardware 13
6. Assembly instructions electronics 17
7. Partlist mechanics 26
8. Mechanical assembly instructions 29
9. Charching YETI batteries 41
10. Software installation and initial steps 48
11. Preparation for operation 63
12. YETI Calibration 66
13. YETI Programming 69
14. Extensions and upgrade modules 85
xx. APPENDIX 104
A. Overview of Yeti functions 105
B. Diagram YETI 109
C. Diagram Display module 110
D. Diagram US module 111
E. Diagram RS232 IR 112
F- Diagram USB IR 113
G. Flatcable connections 114
H. Error tracking 115
I. Installing upgrade kits 117
J. Calibration- and test program 118
K. Akku ADC values 121
CONTENT

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1. PRODUCT DESCRIPTION YETI
1.1. What kind of robot is the YETI?
YETI is a walking robot man, named after “the abominable
snowman”, a hairy giant, who is supposed to live in the
Himalayan Mountains. Just like the legendary giant, our robot
is walking on two big feet.
Our YETI however is supplied with a microprocessor brain and
a computer program, controlling a number of servomotors to
move its legs and feet.
1.2. Specications:
YETI ROBOT
Motor: 2 servo motors (5 Volt)
Processor type: ATmega8L
Programming
language: C
Power source: 4 pcs. AA Accu
4.8 - 6 Volt
Power consumption: 10 mA minimum
600 mA maximum
Communication: Infrared and I2C bus
Extensions: Possibility for two extensions by a
    atcable
Height 278 mm
Width 155 mm
Depth 100 mm

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2. YETI GENERAL INFORMATION
2.1. Who or what is YETI?
As already mentioned YETI is a walking robot, named after
“the abo-minable snowman”, a hairy giant, who is supposed to live in
the Himalayan Mountains.
Just like the legendary giant, our robot is walking high on his two big
feet. Our YETI however is supplied with a microprocessor brain and
a computer program, controlling a number of servomotors to move its
legs and feet. So it can walk forwards and backwards and even make
left and right turns.
For each step YETI must move one feet followed by he other just like
humans do. Therefore he needs two servomotors controlled by a brain
(microprocessor). A servomotor has an internal gearbox and because
of this it is a very powerful motor.
To control the motor rotation and speed, the servomotor also contains
an electronic circuit which is a Puls Width Modulation (PWM) control.
This PWM control allows the servomotor to make a very accurate
rotation step.
YETI has a front servo and a bottom servo. The servo at the front puls
moves the feet upwards. The forward and backward move is made by
the bottom servo. In this manual another name for bottom servo may
also be leg servo!

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2.2. How can we use the YETI robot?
• Load different example programs into the YETI.
• Load self-made programs into the YETI.
• Add assembled electronic extension units to enable the YETI to
avoid obstacles or to measure distances.
• Add self-made electronic extension units.
• Let YETI communicate with your computer by wireless infrared
signals.
• Control YETI by wireless infrared signals from your computer or
from your remote TV-control set.
• Let YETI play melodies or make sounds
• Switch off and on his LED-eyes.
• Modify the YETI hardware and YETI’s face, for example by a
display or a LED mouth.

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2.3. YETI may be activated by 3 simple steps
1. Assemble the mechanic and electronic modules of YETI
following the instructions in the manual.
2. If you use accumulator-packs, charge the rechargeable devices
to 100 %.
3. Activate the main YETI switch at the bottom of the robot.
A few seconds later YETI will stretch his legs and proceed by giving a
demonstration of his abilities, following a standard example program in
the processor’s memory.
Nowthisdoesnotseemtobesodifcultanditlookslikeweareready
by now. But the real work is still to come and this is just an ouverture.
We may now concentrate on writing our own programs and modify the
robot’s abilities and looks in a more creative phase.

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2.4. Loading an example program into the YETI memory
We will be using harmless invisible infrared light signals to load an
example program into the YETI memory. In fact, the supplied COM-port
adapter contains a RS232-infrared transceiver, which must be
connected to the COM-port of your PC. The YETI robot contains a
built-in infrared transceiver, being located behind both small openings
at the robot’s back. The computer COM-port adapter is available as an
USB-module as well. The ASURO robot, another programmable robot
in our robotic range, is using the same IR-transceiver system.
Loading a program into the YETI memory will overwrite the
existing program in YETI’s memory. The default example
program in the memory will be deleted. This however is no pro-
blem, as it may be reloaded from the PC into the memory at any
time.

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2.5. Loading a YETI program into the robot
• Connect the COM-port adapter (or the USB adapter) to
your PC.
• Start the Flash program at the computer.
• Select the COM-port for the COM-port adapter in the
Flash program at the computer.
• Select the YETI program in the Flash program.
• Allow the holes in the YETI’s back to be directed to the
upper side of the COM-port adapter.
• Switch off YETI’s main switch.
• Press the button “Programming” in the Flash program.
• Switch on YETI’s main switch (within 10 seconds).
• Now the YETI program will be transferred into the YETI
processor memory.
• Wait until the YETI program has been loaded.
• Switch the YETI off and then on again.
• Wait for 3 seconds.
If everything is OK, YETI will now start executing its new program.

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2.6. Add-on kits
You may easily add extra (but non included) modules to the YETI
robot, to allow YETI to do much more. How about adding an ultrasonic
transceiver, allowing YETI to sense the distance to obstacles and avoid
these objects while walking around?
You also may add a display to YETI’s body to show output messages
or data. Add-on kits usually contain a printed circuit board (PCB) and
may be supplied with or without electronic components. The add-on
kitsaremadetotintotherobot’sheadandwillbeattachedtothe
skull just above his eyes.
Of course you may also design your own PCB’s by using the experi-
mental PCB-set. This module will be attached to YETI’s head and will
be located at the tiny roof.
Aatcableisusedtoconnecttheadd-onmodulestothemainPCB
(and to the microprocessor’s I2C bus in the robot’s skull as well), using
an I2C-bus system.

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2.7. The communication between YETI and PC
Pressing the “Programming”-Button in the Flash Program will activate
the Flash program to contact the YETI robot for 10 seconds. If YETI
responds, the YETI program will be transferred. YETI however will only
respond to the PC if the contact is tried within a 3 seconds period fol-
lowing YETI’s switch on. If YETI is not being contacted within the 3
seconds period, the robot will proceed by starting the program in its
memory. In case the YETI does not respond, the Flash program will
output an error message after 10 seconds.
Reports from ASURO-users describe potential problems in data
transfers.EspeciallytheRS-232adaptermaybecausingdifcultiesby
generating error messages.
These problems may be avoided by:
• Providing a good visible contact between IR-transmitter
and -receiver.
• Using the latest Flash software release.
• Using fully charged battery packs.
• Screeningthesystemsfromarticiallightsources(especially
 uorescentlamps).
• Using an USB-adapter (especially in case the
RS-232 voltage is low).

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4. WHO OR WHAT IS YETI?
4.1. Summary
AsdiscussedintherstchaptertheYETIisamythicalgure,
the abominable snowman, living in the Himalya Mountains and clumsily
walking on two big feet.
Our YETI is a tall, upright standing robot, equally walking on two big
feet and being able to move forward or backward or make a left or a
right turn.
Every step forward or backward will start by balancing on one foot and
moving the opposite foot. Basically two servos will be executing these
movements. A servo is a special motor type, including a gear. Gears
are used to reduce speed, but will equally increase the motor’s torque.
Additionally the servo is equipped with impulse-controlled electronics,
allowing an exact positioning of the servo’s rotation angle.
The YETI is equipped with two servomotors, located at the frontside
and at the bottom side. The servo at the frontside rises YETI’s feet in
order to move them (and is named the “feet-servo”) and the servo at
the bottomside moves the legs (including the feet) one by one (the
“legs-servo”).
4.2. The basics of walking
YETI is balancing on one foot and is moving the opposite foot. To do so
YETI pulls the outer side of the “balancing” foot upwards and simulta-
neously presses the outer side of its “moving” foot downwards. These
movements will bend YETI’s body over to the “balancing” foot, which is
now carrying the main part of the robot’s weight. In a next phase YETI
will shift its “moving” foot forward, completing the movement process.
The “moving” foot is now turning into a “balancing” foot and vice versa.
In the walking process these movement are constantly being repeated.

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Detailed explanation
Starting from stillstand, the YETI starts rotating the feet servo clockwise
as seen from the front side. These rotations will result in two move-
ments:
Inarstphasetherigthsideofthefeetservoisrising,pullingtheouter
side of the right foot upwards. This action might bend the body to the
right, but this movement is impossible as long as the main part of the
weight is still resting on the inner side of the right leg.
At the same time the left side of the feet servo is lowering, pressing the
outer side of the left foot downwards. This action is lifting the left leg
upwards, bending the body to the right and transferring the main part of
the weight to the right foot.
If YETI raises his right foot a little bit too much, the left foot will bend
YETI’s body over the equilibrium point, causing the robot to fall down to
the right side. YETI must raise his right foot just high enough to prevent
the left leg from pushing him beyond the equilibrium. The closer the
body reaches the equilibrium, the greater percentage of the weight is
resting on the right foot and the easier the robot is able to move his left
foot.
At this point the legs servo is activated. The legs servo moves YETI’s
left leg forward as far as possible. While moving the left foot forward
from behind, the body will also be bended up to a position halfway the
left foot, but still following the line of the right foot. YETI is still balancing
on his right foot. As soon as the left foot has reached its ultimate
position, the robot raises the outer side of the left foot and
simultaneously presses the outer side of the right foot downwards.
These actions will move the body and its weight as well (including the
equilibrium point) from the right foot to the left one. Again we must be
careful to prevent YETI to move too far to the left, which would result in
falling down.
The movement phases will symmetrically be repeated for each
single leg.

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4. HARDWARE
4.1. YETI main PCB
YETI’s main printed circuit board (PCB) is equipped with an Atmega8L
microcontroller chip. The microcontroller is connected to a big, round
beeper and to both red LED’s at the front side. A great number of other
microcontroller pin connections, e.g. the I2C bus, are routed to the
20-pin connector at the rear side directly. This connector provides an
extensionporttootherhardwarebyaatcable.Bothblackconnec-
tors next to the red LED provide the connections to both servos. Three
white connectors serve the connectors for the main switch and for both
battery packs.
4.2. Flat cable connections
Thedesignersreservedfourofthetwentyatcableconnections.
Pin 19 is used for VCC and pin 7, 8 and 20 for GND.
Allremainingatcableconnectionsareconnectedtoadedicated
microcontroller pin. The pin numbers are listed with the assigned
microcontroller pin functions.
Microcontroller pins may be used in several modes, depending on the
programming mode. Please check the microcontroller’s datasheet or
manual for details.

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4.3. Flat cable connections
Moreinfoaboutatcableconnections:(seepage.20)
Pin 1 SCL
Pin 2 SDA
Pin 3 PC3(ADC3)
Pin 4 PC2(ADC2)
Pin 5 PC1(ADC1)
Pin 6 PC0(ADC0)
Pin 7 GND
Pin 8 GND
Pin 9 AVCC
Pin 10 PC6(RESET)
Pin 11 PB5(SCK)
Pin 12 PB4(MISO)
Pin 13 PB3(MOSI/OC2)
Pin 14 PD3(INT1)
Pin 15 PD6(AIN0)
Pin 16 D7(AIN1)
Pin 17 PD0(RXD)
Pin 18 PD1(TXD)
Pin 19 VCC
Pin 20 GND
4.4. YETI experimental extension set
Summary
The experimental extension set has been designed to set up your own
electronic designs and connect the experimental modules to the micro-
controller.

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4.5. Flat cable connections
Thedesignersreservedfouroftwentyatcableconnections.
Pin 19 is used for VCC and pin 7, 8 and 20 for GND.
Allremainingatcableconnectionsareconnectedtoadedicatedmicro-
controller pin. The pin numbers are listed with the assigned microcon-
troller pin functions. Microcontroller pins may be used in several modes,
depending on the programming mode. Please check the microcontrol-
ler’s datasheet or manual for details.
Pin 1 SCL Serial Clock (for I2C communication)
Pin 2 SDA Serial Data (voor I2C communication)
Pin 3 PC3(ADC3) Digital input/output or analog monitor input
Pin 4 PC2(ADC2) Digital input/output or analog monitor input
Pin 5 PC1(ADC1) Digital input/output or analog monitor input
Pin 6 PC0(ADC0) Digital input/output or analog monitor input
Pin 7 GND GND (several connectors to prevent signal noise)
Pin 8 GND GND (several connectors to prevent signal noise)
Pin 9 AVCC Analog reference-voltage for AD-converters
Pin 10 PC6(RESET) Microcontroller reset pin
Pin 11 PB5(SCK) Digital input/output
Pin 12 PB4(MISO) Digital input/output or I2C function pin
Pin 13 PB3(MOSI/OC2) Digital input/output or I2C function pin or Timer2 pin
Pin 14 PD3(INT1) Digital input/output or external interrupt
Pin 15 PD6(AIN0) Digital input/output or analog testinput
Pin 16 D7(AIN1) Digital input/output or analog testinput
Pin 17 PD0(RXD) Digital input/output or RS232 input
Pin 18 PD1(TXD) Digital input/output or RS232 input
Pin 19 VCC VCC
Pin 20 GND GND (several connectors to prevent signal noise)

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5. ASSEMBLY INSTRUCTIONS ELECTRONICS
First of all please check if all parts in the kit are complete.
5.1. Soldering job
The layout on the PCB clearly shows where to mount each component.
When you want to see more detailed information, please study the
diagram, pictures and drawings for extra help and information.
When we assemble a PCB we always start with the lowest passive
components. Normally these are the resistors followed by the capaci-
tors. After soldering, cut the wire ends of the components directly, so
you always keep enough space for the soldering of the other compo-
nents on the PCB.
Before you start soldering, we always advise to insert the active com-
ponents (transistor, IC, diode) so you already can align their pins when
they do not fit properly. Often the legs of such components need some
extra bending to make them fit. At last you solder the IC sockets or the
active components.
IMPORTANT
The Elco and IC have a polarity so you should be careful to solder
them in the correct position.
WARNING
NEVER start with the soldering of an IC and when possible always use
a IC socket to avoid mistakes. When an IC is soldered, it is very dificult
to remove it again.
TIP
The IC-pins can be bend and aligned very simple on a hard flat
surface like a table! Just put all pins inline on the table and bend the IC
carefully to the correct alignment.
Technical questions see; www.arexx.com --> Forum
www.roboternetz.de --> Forum

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1. Preheat the solder area which
must be soldered AND the com-
ponent wire with the tip of the
iron. Do NOT overheat it!
2. Add some solder to the
soldering area and
component wre but NOT
TO MUCH!
3. Ziehe den Lötdraht zurück
und lasse das Lötzinn richtig
fließen.
4. Take away the soldering iron
and DO NOT MOVE the
component or PCB!
5. Cut away the long component
wire just above the soldering spot.
The END RESULT is a nice and
shinny soldering spot which is
attached to the PCB copper and
component wire.
long-nose plier
Solder
0,8- bis 1mm
Soldering iron
(15 to 30W)
Diagonal cutter
Soldering iron
stand
5.2.Necessary tools
CAUTION
• Read this manual carefully in advance to fully understand how to assemble this product.
• Children below 14 should can only assemble this product with the help of adults.
• Be careful about tools. Especially be careful about sharp tools such as nippers or cutter knife
to prevent any injuries or accidents.
• Never assemble the kit when a younger child is around. The child might touch sharp tools or
swallow parts and a vinyl bag.
• Be careful about sharp edges of parts.
* Do not mix old and new or recharchable and non rechargeble batteries.
• Take out the batteries when you do not use the YETI for more than a week
•Thespecication,shapeandsizeoftheproductarebesubjecttochangewithoutpriornotice.
Screwdriver set
Necessary Batteries:
AA Batteries, 3 Pieces
(not included)
5.3. Soldering techniques:
Hold the iron like
a pencil
Only add a little solder each time
Correct position for professional soldering
5.4. Troubleshoot soldering mistakes:
PERFECT SOLDERING
The soldering surface
looks nice and shinny
Not enough solder
Solder did not flow
Solder bridge
Two seperate solder spots are
connected to each other
Cold PCB
Solder is attached to
comonent wire but not to
the PCB copper
Only use lead free ROSIN CORE solder!
Never use any liquid- or paste flux!
PASTE

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5.4. Assembly main PCB
IMPORTANT see 5.5 (Diagram) and 5.6 (Pictures)
YETI parts list
Nr. Name Pcs.
PCB1 Main PCB 1
IC1 ATmega8-l (polarity!) 1
IC2 SFH5110 IR-receiver-IC (polarity!) 1
R1 10K / 0.25W / 5% (Brn, blk, or, gld) 1
R2 120K / 0.25W / 1% (Brn, red, blk, or, brn) 1
R3 100K / 0.25W / 1% (Brn, blk, blk, or, brn) 1
R4 220R / 0.25W / 5% (Red, red, brn, gld) 1
R5 220R / 0.25W / 5% (Red, red, brn, gld) 1
R6 470R / 0.25W / 5% (Ylw, vio, brn, gld) 1
R7 470R / 0.25W / 5% (Ylw, vio, brn, gld) 1
R8 4K7 / 0.25W / 5% (Ylw, vio, red, gld) 1
L1 10uH (Brn, blk, blk, silver) 1
C1 220uF/16V (polarity!) 1
C2 10nF (103) 1
C3 100nF (104) 1
C4 100nF (104) 1
C5 220uF/16V (polarity!) 1
C6 100nF (104) 1
D1 SFH415-U IR-LED (polarity!) 1
D2 LED Red, 5MM (polarity!) 1
D3 LED Red, 5MM (polarity!) 1
Q1 Quarz, 8Mhz / 3 PIN 1
SP1 Beeper, 5V, (KC1206) (polarity!) 1
IC socket 28 PIN, IC socket (polarity!) 1
JP1 3 PIN, PCB type, black 1
JP2 3 PIN, PCB type, black 1
JP3 3 PIN, PCB type, white 1
JP4 3 PIN, PCB type, white 1
JP5 3 PIN, PCB type, white 1
CON1_PCB Connector, male, 20 pins,
  foratcable/90degreeangle 1

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6.3. Diagram YETI