(403) 284-2876 info ...enter the exciting world of mini-sumo! samri sumo is a powerful and fun kit...

JCM InVentures 24 http://www.www.jcminventures.com

CYBUG Robotic Life Forms JCM Inventures has a wide selection of robotic life form kits, including...

Cybug SMarTi This happy guy gives you a great introduction to surface mount soldering, while letting you practice your through-hole soldering techniques. Surface mount soldering is the way of the future, and is the method used to make many of the electronics in your home! Difficulty Level: Easy

Cybug Hornet Once you complete the Cybug SMarTi, move on to this more advanced kit. The Hornet includes all necessary components including surface mount resistors, ICs and LEDs, two DC Motors, and flexi-ble solar cells you can use to shape wings. Difficulty Level: Advanced

For questions or support please contact: JCM Inventures ( aka JCM Electronic Services ) (403) 284-2876 http://www.jcminventures.com [email protected]

What’s in this bag? This kit contains detailed instructions with photographs, all mechanical and electronic components ( over 40 parts ), quality double sided circuit board, and theory of operation. You’ll need 6 AA NiCad batteries, electronics grade sol-dering pencil, and some basic hand tools to complete this project! No prior knowledge of electronic fabrication required!

Introducing… The next evolution of Cybug Scarab! The new Scarab includes a sleeker low-profile circuit board, on-board power and motor connectors, and a more advanced microprocessor-based upgrade module! Difficulty Level: Easy

Ver 1b


Enter the exciting world of Mini-Sumo! SAMrI Sumo is a powerful and fun kit that teaches you about many aspects of robotics. With this kit, you will:

• Solder a circuit board!

• Assemble a motor gearbox!

• Bend your own chassis!

• Customize the behavior of your Sumo with programming!

• Compete in international Mini-Sumo competitions! Compete with your friends and classmates! Can your custom programming make your Sumo the best? With many enhancement possibilities, your Sumo is limited only by your creativity and ingenuity! SAMrI Sumo can also be used as a general purpose programmer for the powerful Atmel ATMega8L microcontroller.

Made in Canada © 2007


Assembly Notes

Caution: Building an electronic project is enjoyable, but please resist the temptation to hurry ahead and omit instruction steps. Please be sure that you:

• Read all instructions carefully.

• Read the entire step before you perform each operation.

• Be careful when handling a hot soldering iron. Tip temperature may approach 700o F.

• Make certain that you wear appropriate safety glasses at all times and work in a well venti-lated area.

• When cutting wires, make sure that the cut end is directed away from everyone.

• Solder a part or group or parts only when you are instructed to do so.

Tools:

You will need these tools to assemble your kit.

• Wire Strippers

• Diagonal Cutters (Side Cutters)

• Long Nose Pliers

• Soldering Iron ( 25 to 40 Watts )

• Stiff Ruler ( metric / imperial )

• Masking Tape

• Hack Saw (optional)

• File (optional)

• Safety Glasses!

Please follow all instructions carefully, and be very careful that you use safety glasses at all times when building your kit! Be careful when handling your soldering iron… the tip is very hot!


Need More Oomph?

The L298N motor controller can deliver up to 4 Amps of DC current. Outfit your Sumo with more power and bigger motors for a little extra push! If you do, be sure to attach an adequately large heat-sink to the L298N. It will get very hot, and this can prevent damage to you and the device.

More MHz The ATMega8L runs at a default 1 MHz clock speed using an internal clock oscillator. Using the XTAL, C6, and C7 footprints to the left of the micro, you can upgrade the 8L’s clock speed with a new crystal oscillator up to 16 MHz. Many of this microcontroller’s instructions operate through a single clock cycle, allowing for a maximuim of 16 Million Instructions Per Second (MIPS) at 16 MHz. You can find the ATMega8L datasheet on the Atmel website at http://www.atmel.com.

Technical Data You can find resource pages, detailed schematics, and other technical infor-mation about all of our products on our website. Visit http://www.jcminventures.com for more information.


Enhancements and Upgrades You may have noticed some footprints that went unused on your circuit board. There are many things you can do with SAMrI Sumo, limited only by your creativity and imagination.

Rangefinder The SAMrI Sumo can be upgraded with the Sumo Rangefinder kit installed below the reset pushbutton. More information is available from our website. This kit allows Sumo to sense how far away objects in front of it are, and change its behavior accordingly. After you’ve installed the rangefinder on Sumo’s circuit board, you’ll have to download the latest version of SUMOSen-sei from our website to program Sumo’s new sensor.

Prototyping Area On the right side of Sumo’s circuit board, you’ll see a small prototyping area. You can use this for whatever you like! Custom circuits can make your SAMrI Sumo very powerful. +5VDC Power and Ground are provided in the two verti-cal strips, and once you are done building you can use any analog and digital signals with the ATMega8L.

Port Pins Surrounding the ATMega8L microcontroller are pads you can use to connect directly to the Mega8’s various input and output ports. The pads closest to the pins are identified by the port pin labels, and +5VDC power and ground are provided on the top side of the microcontroller, as labeled.

Additional Reflective Sensors You’ve already installed Q1 and Q2. Additional sensors can be installed on the bottom of the circuit board at Q3, Q4, and Q5. The signals from these sensors are transmitted to the upper board through board connectors of the same names. There are pads beside each of these board connectors that you can use to wire the sensor signals to whichever ATMega8L port pin you would like: 2 pads on either side of Q4, and one each beside Q3 and Q5. To use these additional sensors in your program, you’ll have to write some cus-tom code in C using…

WinAVR

WinAVR is a suite of powerful pro-gramming tools for the Atmel AVR series of microcontrollers. If you’re a more experienced programmer, you can create some very powerful microprocessor applications using the ATMega8L for any function you wish. The SAMrI circuit board has been designed so you can use it solely as a microcontroller programmer. For more information, visit the Western Canadian Robotics Society website at http://www.robotgames.net or the WinAVR website at http://winavr.sourceforge.net. WinAVR is freely distributed under the GNU public software license.


SolderingSolderingSolderingSoldering Soldering is the most important operation you will perform while constructing this kit. A good solder connection will ensure a solid electrical connection between the part and the circuit board. A bad solder joint can prevent an otherwise well assem-bled kit from functioning properly. It is simple to make a good solder connection if you follow a few simple rules: few simple rules: few simple rules: few simple rules: 1. Use the right type of soldering iron. A 25 to 40 Watt pencil type iron intended

for electronic work with a 1/8” pointed tip works best. Use a rosin-core solder on diameter approximately 0.032” and a 60/40 lead/tin ratio.

2. Keep the soldering tip clean by wiping it frequently on a wet sponge or cloth: then apply solder to the tip to give the entire tip a wet look (tinning the tip). When solder tends to “ball” or does not stick to the tip, the tip needs to be cleaned and re-tinned.

How to SolderHow to SolderHow to SolderHow to Solder

• Install the component on the board, flaring the leads on bottom side slightly

(so the part does not fall out when the board is flipped!) Flip the board upside down.

• Touch the freshly tinned soldering iron to the point where the component wire meets the board. Hold for 1 second!

• Touch the solder to the opposite side of the component wire/board junction and allow solder to melt and surround pad en-tirely.

• Remove the solder, then remove the soldering iron by dragging the iron up the component wire.

• Clip off excess component wire with side-cutters.

How do you know when you’ve made a How do you know when you’ve made a How do you know when you’ve made a How do you know when you’ve made a good connection?good connection?good connection?good connection?

Too Much Solder? Solder will ball up like an iglooiglooiglooigloo. Too Little Solder? Solder will lie flat like a pancakepancakepancakepancake. Just the right amount? Solder will look like a volcano! volcano! volcano! volcano!

Having a hard time? Check out our website for a great soldering tutorial! http://www.jcminventures.com


Component Identification: The function of all the components listed below are described in the assembly instructions. Please look through your kit and identify each component type! Resistors will be described by their color-code, a sequence of colored bands which identify their resis-tance’s. The color lines are read from left to right with the gold or silver band being the right-most

band. Resistance is measured in “ohms”, frequently symbolized by the Greek ‘ Ω ‘ symbol.

• The first two bands identify the first two digits of the resistance value.

• The third band is the number of zero’s ( or multiplier )

• The fourth band indicates the tolerance of the resistor and is typically gold (5%) or silver (10%)

The resistor depicted above is a 1000 ohm resistor, or 1k Ω. Brown, black, red, gold.

To get a better look at resistor color bands, check out our full color manual online! Capacitors will be called out by their capacitance value in uF (microfarads) or pF (picofarads) and type: monolithic or electrolytic. The larger electrolytic capacitors (left) will have their values printed on them and have the negative lead marked with a large black or white stripe. The small monolythic capacitors (right) will be labeled as 104 (1 x103 pF) or 103 (1x102 pF) and have no polarity.

Colour 1st Band 2nd Band 3rd Band

Black 0 0 No Multiplier

Brown 1 1 0

Red 2 2 00

Orange 3 3 000 ( K )

Yellow 4 4 0000

Green 5 5 0,000

Blue 6 6 000,000 ( M )

Violet 7 7 0,000,000

Gray 8 8 00,000,000

White 9 9 000,000,000


Troubleshooting If the following steps don't help there are more troubleshooting resources on our website at: http://www.jcminventures.com

Problem: SAMrI Sumo doesn’t do anything! Sounds like he has an energy crisis. Is switch S1 in the on position? Have you installed the AT-Mega8L IC in it’s socket? We suggest you check carefully that you have not attached the battery wires backwards. Perhaps your batteries are simply low on power and need to be replaced. Problem: SAMrI Sumo’s Power LED lights up, but he doesn’t move anywhere. This could be caused by a number of different things.

1. Did you customize your command sequence with SUMOSensei and tell your Sumo to move at 0% speed?

2. Is your ATMega8L Installed correctly? The notch in the IC should point towards the the left side (LED side) of your circuit board.

3. Did you solder both sides of all 11 board connectors? These are the brass wires that carry signals between the upper and lower circuit boards. You may need to retouch these joints with additional heat and solder.

4. Look carefully at all the solder joints on the L298 motor controller, top and bottom, and make sure every pin has been soldered and that there are no solder bridges between adjacent pins.

Problem: Sumo moves OK, but the Power LED isn’t working. Chances are you have put his LED in backwards. Make sure the flat part on the base of the LED is facing the top of the circuit board (towards the DB25 connector). Problem: SAMrI Sumo doesn’t move forward, he only backs up and turns! This can happen when the sensors aren’t reading the ring surface correctly, and usually means they are too close or too far away. Press down on the front of the chassis to flatten out the first bend until the reflective sensors are between 1mm and 3mm away from the surface of the ring. Sensor problems can also happen when the board connectors labeled Q1 and Q2 haven’t been properly soldered, or when the sensors are not installed label-side out. This can also occur if you are using 6 new alkaline batteries in your SAMrI. Too much power to the motors can cause noise in the sensor circuit and make your Sumo think it’s seeing the edge all the time. This can be solved by using 6 batteries of a different type: NiCad, Ni-MH, or Li-Ion work well. Alternatively, you can use 5 AA alkaline batteries and short the 6th battery position. You may also want to try manually adjusting the sensitivity of the reflective IR sensors. Go to Options >> IR Sensors… in SUMOSensei to do this. Problem: SAMrI Sumo rolls right off the edge of the ring, without backing up. This is another sensor problem. Adjust the angle in the front of the chassis until the reflective sensors are between 1mm and 3mm away from the surface of the ring. Sensor problems can also happen when the board connectors labeled Q1 and Q2 haven’t been properly soldered, or when the sensors are not installed label-side out. Problem: I can hear the motors in the gearbox spinning, but Sumo is not moving! Occasionally the hex collars in your gearbox will come loose, and you’ll need to tighten their set screws. If you drilled holes in the chassis before bending it, simply flip over SAMrI Sumo, turn the wheels until the set screws are visible, and use the allen-key that came with your gearbox to tighten them. If your chassis is without holes, you’ll have to take the gearbox off of the chassis to do this.

Still not working? Visit the support page on our website or Drop us an email at [email protected]

Please include circuit board photos (both sides) if possible!


SUMOSensei Continued from previous page. To change the performance of your Sumo, adjust the command sliders in the Commander window. Note the changes in the command sequence to the right. When running, your SAMrI may behave differently based on the black and white materials you use for your competition ring. If the default values for the reflective IR sensors aren’t working, you can try manually adjusting their sensitivity in the Options >> IR Sensors… window. When you are ready to see how your new command sequence makes your SAMrI Sumo behave…

1. Save your sequence file by clicking File >> Save 2. Press the Generate button to translate your command se-

quence to a C Program file! If you would like to view the Source Code SUMOSensei has generated, select View >> Source Code.

3. Plug your Sumo into the parallel port of your computer or an extension cable no longer than 2 feet, and press the Compile and Program button. SUMOSensei will now translate the Source Code (in C) into machine language instructions under-standable by the ATMega8L microcontroller.

4. Follow the instructions that appear on screen to program the ATMega8L with the machine code.

You have now customized your SAMrI Sumo! You can tweak your com-mand sequence and program your Sumo as many times as you like, until it behaves just the way you want it to.

Suggested Settings Try these settings and see how your Sumo responds!

Sumo Mode - Forward speed sliders to 80%. Reverse / Turn speed sliders to 40%. Reverse / Turn time sliders to 1 second. Sneaky Mode - Forward speed sliders to 50%. Reverse / Turn speed sliders to 80%. Reverse / Turn time sliders to 0.5 seconds. Rambo Mode - Forward speed sliders to 100%. Reverse / Turn speed sliders to 100%. Reverse / Turn time sliders to 0.25 seconds.


LEDs are special types of diodes that emit light. LEDs come in a multitude of colors and sizes. The negative lead of any diode is called the cathode, while the positive lead is called the anode. The cathode on a Light Emitting Diode can be identified by a flat indenta-tion on the plastic case, as well as a shorter lead length. The lead of the anode will be longer. Switches are used to connect or disconnect one circuit from another. Simple switches like these have no polarity, and can be installed in any orientation. The switch on the left is a pushbutton switch, and the switch on the right is a slide switch. The pushbutton switch in your kit is longer in one dimension than in the other. Reflective Sensors are sensors that act both as an LED and a phototransistor. These sensors have two sides: the LED side can be identified by no label on the case and a clear plastic window on the face of the sensor (left); the phototransistor side can be identified by a label on the case and a black window on the face of the sen-sor (right). Take note of the location of the case label on your reflective sensors. DB-25 connectors such as these are used for parallel data transmissions. You may recognize this shape: look at the back of your computer, and you’ll notice this connector’s female counterpart! Later you’ll use this connection to program your SAMrI with soft-ware on your computer. If you look carefully on the face of this compo-nent, you’ll see a number that identifies each pin. There are 13 pins on top, and 12 on the bottom: the orientation of these pins match up to the edge connector labeled DB25 on the top of your circuit board.


Quantity Description Check Off

1 330 ohm resistor

3 4.7k ohm resistors

6 100 ohm resistors

2 Reflective Optical Sensors

1 78L05 5V Voltage Regulator

10 104 (0.1uF) monolithic capacitors

1 220uF electrolytic capacitor

1 1000uF electrolytic capacitor

1 Colored LED

1 L298N Motor Controller

1 ATMega8L Microcontroller

2 14-Pin integrated circuit sockets

1 25-Pin D-Sub Male Connector

1 DC motor gearbox set (complete with 2 DC motors)

1 Aluminum chassis plate

1 Printed circuit board

1 Length of brass wire

2 Yellow wheels and rubber tires

1 9V Battery Connector (Holds 6 AA batteries)

1 Double sided foam tape

1 Reset Pushbutton Switch 1 On/Off Switch

Integrated Circuits will be called out by their part number, found printed on the top of their case. Pin numbers of the integrated circuits always start ( 1 ) with the top left pin and num-ber counter-clockwise around the chip. The top of the chip is always identified with a dimple or notch.

PARTS LIST Take a moment to check that your kit contains all these components.

Pin 1

Not Included: 6AA NiCad Batteries (Li-Ion or NiMH work as well)


SUMOSensei You can get a free copy of SUMOSensei from our website! Visit http://www.jcminventures.com for more information. Your computer must have a 25-pin parallel port to use this software. (your printer might be connected to this port) After downloading the installer package, uncompress the files and double click on SETUP.EXE to begin installation. You must have administrative rights on your computer to install applications on Windows XP. Depending on the way your computer is configured, additional components may need to be installed, and the installation program will do this for you. Components may include:

• Windows Installer 3.1 - this installs the application to your computer

• .NET 2.0 - this tells the application how to interact with your hard-ware and operating system configuration

These components are authored by Microsoft and are safe for you to install. After this step is done, follow the on-screen instructions to complete the instal-lation of SUMOSensei. If you do not wish to change the default installation location, simply press NEXT and finish the installation. Default locations are recommended. When SUMOSensei is done installing, you should have a new icon on your desktop and in the Programs section of your Start menu under JCM Inven-tures Inc. Start the application by clicking this icon! We recommend you briefly read the included help file to familiarize yourself with SUMOSensei. SUMOSensei help can be opened through the Start menu or from within the program by clicking Help >> Contents or by pressing F1. Take a look around! SUMOSensei allows you to change the behavior of SAMrI Sumo by adjusting control sliders. Certain sliders adjust speed, and others adjust timing. Click File >> Load… and open the demo.sbs file. This sequence file holds the instructions that make up the default performance of your Sumo. Read through the instructions in the Sequencer window and compare them to how your Sumo behaves in the ring. When you are ready to begin customizing your Sumo, click File >> Save As… to modify the demo sequence file, or start a new sequence file by selecting File >> New. It is not recommended that you change the demo file!

Continued...


FABRICATION At this point, your circuit board should still be standing straight off the gearbox. The last step in building your SAMrI Sumo is to bend the top part of the circuit board back. See the cover photo for reference. It is a good idea to insulate the underside of the circuit board from the battery pack; you can use several layers of electrical tape to do this. If you’ll look between the two circuit boards, you’ll see three small circuit board connectors. Holding the bottom circuit board firmly in place against the motor gearbox, bend the upper circuit board until it comes to rest on the battery pack. This will break the three small board connectors that originally held the boards together. You may cut these first if you like.

Bring Your SAMrI to Life Construction is complete, and now it’s time to power up your Sumo! If you haven’t already installed the ATmega8L microcontroller, do so now (make sure the notch in the microcontroller matches up to the notch in the IC socket). The competition ring we use looks like this: It has an outside diameter of 30 inches, the bordering white ring being 1.25 inches in thickness. Although we use circular rings, feel free to be creative and use any shape you like! The color of your ring must be black with a white border for SAMrI’s sensors to work properly. Place your Sumo in the competition arena and slide the power switch to the ON position. The LED should light up to indicate power is on. The default command sequence programmed into the microcontroller is:

1. Wait 5 seconds (standard mini-sumo regulation delay time) 2. Charge forward at 80% maximum speed! 3. If the white edge of the ring is sensed, back up for 0.25 sec-

onds at maximum speed. 4. Pivot away from the edge for 0.5 seconds at half power. 5. Resume forward motion!

The power levels and timing may change slightly as the batteries weaken. Although this default program is sure to win you many matches, your SAMrI Sumo can be connected to the computer and customized with our free SUMOSensei program!


Use this picture as a reference or for taking notes while you are building your SAMrI Sumo.


FABRICATION Place the following resistors in the identified location. They should be flush with the circuit board. Flaring the leads slightly on the opposite side will help hold the parts in when the board is turned up-

side down for soldering. Note: Ω = ohms. ( ) R1 - 330 Ω Resistor (orange orange brown gold)

( ) R2 - 4.7k Ω (yellow purple red gold)

( ) R3 - 100 Ω (brown black brown gold)

( ) R4, R5, R6 - 100 Ω (brown black brown gold)





SAFETY WARNING: To avoid eye injury when you clip off excess leads, wear safety glasses! NOTE: For good solder connections, you must keep the soldering iron tip clean. Wipe it often on a wet sponge or cloth. ( ) Solder the leads to the circuit board and cut off excess lead lengths. NOTE: No lead should extend more than 1/8” above the circuit board after it has been soldered and cut off.

( ) C3 - 220uf Electrolytic Capacitor (Watch the polarity!) The negative lead of this capacitor

should be installed towards the top of the circuit board. ( ) C4 - 1000uf Electrolytic capacitor (Watch the polarity!) The negative lead of this capacitor

should be installed towards the left side of the circuit board.

NOTE: The label 104 on the monolithic capacitors refers to 10x103 pF or 0.01x10-6 farads (0.1 uF) There is no polarity on this part.

( ) C1 & C2 - 0.1uf ( 104 ) capacitors (small yellow or blue beads) ( ) C5 - 0.1uf ( 104 ) capacitor (by the microcontroller footprint). Solder a second 104 capacitor

below the “SAMrI” logo at the “GND” label. ( ) C8, C9, C12, C13 - 0.1uf ( 104 ) capacitors (on the lower sensor board). You should have 2

104 capacitors left over… save these for later! ( ) Solder the leads to the circuit board and cut off excess lead lengths. If some components have trouble staying flush to the board during soldering… use some masking tape!

Note: Parts are identified by a component number clearly marked on the circuit board and a description of the component.

Value Colour code

R1 - 330 Ω Resistor (orange orange brown gold)

Component Designator on PCB


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FABRICATION In this section you’ll attach the circuit board to the motor gearbox, bend the chassis from the aluminum plate, and install the battery pack. ( ) Insert and solder the remaining two 104 capacitors to the motor gearbox as shown. Do not

trim off leads! ( ) Slide the circuit board (component-side forward) onto the 4 capacitor leads as far as it will

go. The circuit board should be flush with the ends of the motors, and the mounting holes on the motor gearbox should go down.

Recommendation: If you would like, you can add some epoxy or hot glue between the ends of the motors and the circuit board to hold it in place and strengthen the joint.

( ) Solder the capacitor leads to the circuit board and cut off any excess. Use lots of solder here, we want a strong mechanical and electrical connection.

Be safe when drilling holes in metal! Always clamp down your work piece to a solid surface with a piece of sacrificial wood in between. For better control, center-punch your holes before drilling, or alternatively drill first with a smaller bit (1/8”) followed by the full size bit. Using the template on the next page, create the chassis from the aluminum plate: ( ) Using a sharp pencil or scribe, mark the horizontal bending lines on the aluminum. ( ) Mark and drill any holes you are going to drill before bending the chassis (see note 1) ( ) Using a hard ruler or the sharp edge of a table, bend the aluminum according to the

template diagram. Refer to the perspective view or photograph on the cover for reference.

( ) Using foam tape under the front of the gearbox, affix the gearbox / circuit board assembly to

the chassis (as seen in cover photograph). If you drilled mounting holes, use them instead. ( ) Place wheels on the motor gearbox shafts. ( ) Slide the power switch to the OFF position. Install 6 AA batteries into the battery pack, and

place battery pack in the chassis (as seen in cover photograph).


THEORY

In this section we are installing the resistors and capacitors in our SAMrI.

The resistors are used to limit flow of current in the circuit, much as a pinched garden hose would limit the amount of water flowing through the hose! Resistor R1 limits the current flowing to the LED, allowing it to light up when the power is on. R4, R5 and R6 allow your computer to safely communicate with the microcontroller when you program your SAMrI Sumo. More on this later! The components C1 through C13 are called ca-pacitors. These are energy storage devices,

rather like small rechargeable batteries. They can be used for many functions:

• C3 and C4 smoothes ripples in our SAMrI’s supply voltage.

• C8, C9, C12 and C13 remove voltage spikes caused by the two DC motors.

• The two 104 capacitors near where the microcontroller will go make sure the voltage powering the microcontroller is clean and free of ripples. Without these, the microcon-troller might not work at all!


FABRICATION

This part of the fabrication involves mounting the semi-conductors and other hardware onto the SAMrI. Please note: Some of these components are polarity sensitive, and will be damaged if they are put in the wrong way! Please heed all directions! ( ) LED - Colored LED. Mount this component flush to the circuit board, and watch the polarity!

( ) U1 - 78L05 Voltage Regulator. Mount this device as close as possible to the circuit board, with the flat face towards the top of the circuit board. This device sometimes comes with three pins in a straight line that need to be bent to match the triangle-shaped footprint on the circuit board. Simply bend the center pin slightly away from the flat face of the device, and insert.

( ) S1 - On/Off Switch. This device has no polarity. ( ) S2 - Reset Pushbutton Switch. To insert this device into the circuit board, align the switch

leads with the footprint and press down. This part only goes in one way! ( ) Solder the leads to the circuit board and trim off excess lead lengths. To solder components with edge connectors, solder one lead on the top of the board before flipping the board over. Then align the leads on the bottom of the board and solder. Flip the board back over and soldering the remaining top-side leads. ( ) Q1 and Q2 - Reflective sensors. To install the device, start by

trimming all leads to 6 mm in length. Fully insert the device LABEL SIDE UP on the footprint at the edge of the board so that two leads are on top, and two are on the bottom. Each lead should reach just to the end of the pad.

( ) Solder the leads to the circuit board.

( ) DB25 - Parallel port connector. Place this component on the edge so that 13 pins are on the top and 12 are on the bottom of the board. Solder the leads to the circuit board. It is sometimes helpful to file the top edge of the circuit board smooth first! To avoid the chance of damaging the microcontroller,

we will solder IC sockets into the board. The ATmega8L can simply be pressed into the sockets after soldering it to the PCB. ( ) U2 - IC sockets (2). Install these two sockets with the notch in the

plastic aligned with the notch on the silkscreen. Solder the leads to the circuit board.

( ) U3 - L298N Motor Controller. Insert into the circuit board from the top. Before flipping the board over, solder one or two leads from the top to hold this part in place. Solder the remaining leads to the circuit board. A note of caution: when this device is turned on, it can become very hot. Handle with care! You may also want to bolt on a heat-sink.

( ) U2 - Insert the ATmega8L microcontroller into the socket. Be sure to align the notch in the top of the IC with the notches on the

socket and silkscreen.

When installing LEDs, watch the polarity! The negative side is the side with the slightly shorter lead and the plastic base of the LED has a slight flat impression. These must line up with the flat line marking on the printed cir-cuit board!


THEORY The motors we are about to add to our electronic life-form will convert electrical energy from the battery into rotational energy on the motor shaft. The motor uses two very important physical laws:

• Current flow through a wire generates a magnetic field whose strength is proportional to the amount of current.

• Like poles of magnets repel, and unlike poles attract.

A motor works by employing a rotating central armature wrapped with wire to

produce an electric field. Current is fed to this rotating armature by a pair of

brushes touching a commutator. The entire armature and commutator as-

sembly spins within a set of

permanent magnets. When

current is passed through

the armature of a DC motor,

a torque is generated by

magnetic reaction, and the

armature revolves. **

**“Electric motors and generators,” Microsoft ® Encarta ® 96 Encyclopedia. © 1993-1995 Microsoft Corporation. All rights reserved.

Don’t forget to tighten the set-screws in your hex collars! (or your shaft will fall out)


Now install the other brass bushings on the other side of the center plate and add the two plastic posts and one more metal hex shaft as shown!

Add the crown gear, then the remaining three gears as shown, finishing with the gear with the hex collar as shown.

Attach the hex collar to the shaft as shown and tighten the set-screw

Screw the right gear-head plate onto the gear assembly as shown here ( three long screws )

Place a small white pinion gear on the end of each motor and snap the motors into your gear-head assembly with the electrical connection tabs towards the outside. Liberally grease all gears with your blue grease tube. Here’s a hint: The nosiest place in the gearbox is where the fastest spinning gear meets the grey plastic hous-ing. Put plenty of grease between these two and you’ll be good to go!


THEORY Semiconductors are very special electronic components which are based on silicon. With these devices we may:

• turn current on and off

• amplify small signals to large signals

• act as a one-way valve for current

LEDs (Light Emitting Diodes) are also diodes, but are specially prepared with a glowing phosphor which lights bright green when current flows. Remember: if you put this diode in backwards no current will flow, so it won't light!

Voltage Regulators (U1) can change a large, changing DC voltage into a smaller DC volt-age. A smooth, constant DC voltage is re-quired for devices that have specific supply voltage requirements, such as our microcon-troller. The 78L05 regulates any input voltage between 7 and 35 volts down to a constant 5 volt output.

Integrated Circuits (U2 & U3) are small in stature but big in performance! Each one has hundreds or thou-sands of diodes and transistors inside and may perform very ad-vanced functions! The ATMega8L is a microcontroller, a small computer with memory and many advanced functions built into one chip. The L298N helps control flow of current to the motors.

Reflective Sensors (Q1 & Q2) help your SAMrI detect the white edge of the

mini-sumo competition ring. A small IR (infra-red) LED inside the reflective sensor

emits IR light onto the surface of the ring which is either absorbed by the black paint in-side the ring or reflected by the white ring. The

amount of reflected light is detected by another part inside the reflective sensor, the phototransis-

tor. The signal from the phototransistor is sent to the microcontroller for com-mand processing!


FABRICATION

This section details the installation of the battery pack and connection of the lower sensor circuit board to the upper main circuit board. ( ) From the length of brass wire cut 11 short pieces, each 2 cm in length.

( ) Bend each piece into a squared-off п shape, as shown.

( ) Insert each piece where the top circuit board meets the bottom

circuit board. ( ) Solder each piece to the circuit board on both sides,

and trim off any excess length. Do a very good job here: these pieces of wire carry electrical signals between the two circuit boards.

( ) Pass the red and black wires of the battery pack up through

the strain relief holes to the right of the 9V IN footprint. The red wire goes on top.

( ) Solder the wires to the 9V IN footprint. The red wire sol-

ders to the upper (square) pad. The black wire solders to the lower (round) pad.

Here’s the left gear-motor plate. Start by putting the brass bushings in the holes as shown!

Recommendation: Open the Tamiya motor gearbox set and find the two hex axle shafts. For the SAMrI to adhere to mini-sumo regulations, the shaft must be shortened by exactly 6mm. Mark off 6mm and cut using a hack saw - if you cut off too much you can't put it back on! Don't use wire cutters - they're intended for copper and the steel shaft will destroy them. Smooth the cut end with file

6mm


Add the two plastic spacer posts as shown

Place the round shaft and the hex ( 6 sided ) shaft in the holes as shown. Place the hex collar with a set-screw installed over the hex shaft, but don’t tighten it yet!

Now place the brass bushings into the holes shown here in the middle gear-head plate Grease Here!

Use three longer screws to secure the middle plate to the left gear-motor plate. Next tighten the set screw on the hex collar.

Install the four gears shown here over the two metal shafts. Notice the first gear has the fitting for the hex-collor. The last gear is the crown gear.

(403) 284-2876 info ...enter the exciting world of mini-sumo! samri sumo is a powerful and fun kit...

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