• Schematic
• PCB Layout

Assembly instructions

The first items to mount are the ten 0.1uF axial capacitors. Capacitors are not very static or heat sensitive, so they are a good place to get used to soldering if you're not completely comfortable. These capacitors are all the same and come attached together in your bag of parts, so they should be easy to identify. In order to mount them, you must first bend the leads (wires) to a ninety-degree angle so that the leads will fit into the holes in the PCB. Once the leads are bent, you can insert the capacitors into their locations on the PCB. Do one then test. It may take a few to get the spacing right - but this is the spacing used throughout the board so once you get it everything else will turn out right. It doesn't have to be exact. After inserting each capacitor, spread the leads a bit on the back side of the board to hold the capacitor in place. It makes it easier if you rest the board on something like a roll of box tape - this elevates it off your workbench and lets the leads hang down without obstruction.

After soldering, you should make it a practice to visually inspect each completed joint. Take a good look to make sure the solder fills the hole in the PCB and to make sure that all the leads have been soldered. Once you've looked it over and corrected any problems, clip off the excess leads on the back side of the board so they don't stick out too far.

Now for the resistors. See Appendix for resistor identification - there are a lot of different values included in this kit. First step is to lay out all the resistors and identify them. Compare against list of materials (insert resistor component list here). Note that you are given one extra 56 Ohm resistor - save this for later. If you have any doubts proceed by the process of elimination. Colors aren't always easy to distinguish on resistor bodies. Again, resistors aren't very sensitive to static or heat so they are a good way to get used to soldering.

Bend the resistors leads exactly the same way you did the capacitor leads. The component bodies are about the same size, and the hole separation on the PCB is the same. Once again, insert all the resistors at once, turn over and tack down one lead, turn over and inspect, make and necessary corrections, then finish soldering.

Now you've had plenty of practice - 23 components soldered! Time to move on to the harder parts. Next, we're going to put in the Diode at D1. This is the first polarized component on the board. Meaning, unlike the capacitors and resistors we have encountered so far, diodes must be inserted in a particular way - there is a difference between pin 1 and pin 2, and if you insert it the wrong way your board won't work. The appendix discusses polarized components and how to recognize which orientation is the proper one.

Diodes are also static sensitive - electrostatic discharges from touching these components can generate thousands of volts at the lead - enough to damage the component. It is good practice to keep yourself grounded while soldering these. Wrist strap, touching ground, etc. They are also heat sensitive - if you allow the soldering iron to remain on the part for too long, the temperature will damage the part. You have a few seconds - solder the part then move on. If you make a mistake, give it time to cool down before trying to correct it.

Bend the diode leads just like you did for the capacitors and resistors, then insert the diode into the board. The silkscreen on the board shows an outline of the diode, with a triangle and a stripe. The point of the triangle is towards the stripe. The end of the diode with the band around it matches up with the stripe on the silkscreen. See the Appendix for an illustration.

Integrated circuit chips. There are two we are going to solder in this step, the MAX667 Power regulator (U2) and the DS232A serial transmitter/receiver (U3).

Location U4 is reserved for the optional EEPROM. It should be left unstuffed in the default configuration - don't accidentally put the MAX667 in this location! U4 is used to add a serial EEPROM to the Mark III. This EEPROM adds up to 256Kbits of memory to the PIC, for general use. If you choose to use an OOPic instead of a PIC, this EEPROM is mandatory. If you use just a regular PIC, the EEPROM can be useful because the PIC only provides about 300 some odd bytes of RAM storage.

DIPs are polarized and static sensitive. Find pin 1 and make sure that the DIP is oriented properly. Insert into board. The legs of the DIP may be spread too far apart to insert - if so you will need to squeeze them together before you can insert the chip. The easiest way to do this is to insert the legs on one side of the chip halfway, then while holding the chip by the ends apply gentle pressure to simultaneously bend the all legs that are already in the board. Turn board over. Fasten opposite corners with a quick dab of solder then turn back over and check to make sure chips are properly seated.

A 40-pin socket is provided for the PIC chip; this allows the PIC to be easily removed or replaced and also raises the PIC off the surface of the printed circuit board, making room for some resistors to sit underneath the PIC. The socket has a semi-circular notch cut into one end - align this with the corresponding notch shown on the silkscreen. Just like you did with the integrated circuits in the previous step, use a tiny bit of solder to fasten two opposite corners of the socket, then turn the board over and examine it closely to make sure the socket is properly seated. When you are convinced it is, you can solder the remaining pins. Don't forget to go back and make sure the two original corners you soldered get properly fastened.

Tact switch. This push-button switch is used to reset the PIC. The reset switch only fits in two ways, rotated 180 degrees from each other. Either way will work.

Next we will solder in the two small 3-pin shrouded headers (J5 and J6). Notch facing toward the center of the board. Asymmetric - check to make sure that the outline on the PCB matches up with the header. If the PCB outline sticks out a lot, you probably have it backwards.

Electrolytic capacitors. Check for the "-" pin (called the cathode), labeled on the capacitor body with a broad white stripe. The cathode is also the shorter lead. Make sure it goes in the correct hole. The silkscreen has a "+" next to the square pad, the round pad is where the "-" pin goes. This is very important - if power is applied to an electrolytic capacitor in the wrong orientation it may explode! See the Appendix for an illustration.

Resonator Y1. Resonator is not polarized, insert it either way.

LEDs. Light Emitting Diodes - everything we discussed re polarization, heat, static applies here as well. The LEDs are inserted so that the short lead goes into the square pad. The square pad is shaded white on the silkscreen.

Headers, 40-pin and 6-pin at the same time, then the two 3-pin. Again, tack corners (or just one pin, in the case of the 3-pin headers) then turn over to make sure that it is seated properly before doing the final soldering.

Power jack (the black, three-position terminal block) should be inserted so that the wire receptacles face the outside of the printed circuit board.

I²C header (5-pin white header) oriented so that the back (tension relief) is against the DB9 connector.

Power Switch can be inserted either way.

DB9 Serial connector only fits one way. Be sure to solder the locking standoffs to the PCB - this provides strain relief as well as a good ground.

The "Rev2" chassis design has shipped with all Mark III Kits sold since September 2002. The photographs in this section still show the "Rev1" design. However, the PDF drawings of the chassis and scoop are accurate and should be consulted if there is any confusion as to how the pieces fit together.

Parts List and Assembly Drawings

Quantity	Description
1	9V Battery Snap
1	4 AA Battery Holder
1	Chassis Body
1	Chassis Scoop
8	4-40 .375" phillips pan head sheet metal screw
4	Standoff 1.375 inch
5	4-40 .375" phillips pan head machine screw
5	4-40 Hex Nut
2	#4 Internal Tooth Lock Washer
4	#4 Nylon Washer
4	6-32 .500" phillips pan head machine screw
4	6-32 Hex Nut
2	2" Velcro Hook Strip
2	2" Velcro Loop Strip

Note that the 6-32 screws are larger than the 4-40 screws, and the sheet metal screws have pointed tips while the machine screws have square tips.

Full-scale drawings of the Chassis and Scoop are available to show the dimensions and relative positioning of these parts in the Mark III robot:

• Chassis drawing
• Scoop drawing
• Battery Holder

The first step in assembling the chassis is to find the base plate. It is a powder-coated aluminum rectangle, with a large tab bent up in the rear and a small tab bent down in front. Four holes provide the attachment points for the standoffs/servo mounts. A slot on the front end is used to pass the wires from the underside of the chassis to the electronics.

Standoffs to chassis

Servos to standoffs

Use the four #6-32 machine screws and four #6 hex nuts to attach the servos to the standoffs. Make sure the head of the screw is facing the outside edge of the base plate so you have access to it if it needs tightening. The servos should be positioned so that the axle is closer to the rear standoff than the front. This puts most of the weight of the servo in front of the axle. If you want to use the rubber grommets that come with the servos to provide cushioning, mount the grommets on the outside of the standoffs between the standoff and the servo flange. Grommets push the servos toward the outside of the robot, making your robot wider. Be sure to stay within size limits!

Line sensors to scoop

Scoop to chassis

Battery pack/Velcro

Controller board to standoffs

Now you can finally tighten down all the screws that fasten to the standoffs.

9V placement

Attaching the Line Sensors

A length of 1/8" diameter heat shrink tubing is included in the kit. This may be used to keep the line sensor wires together in a neat bundle. At this point in the assembly you will have a good idea of how long the wires for the line sensors have to be and how they will be routed to the circuit board. Cut the heat shrink tubing to length and slip over the wires, shape the bundle to fit, and use a hair dryer on "high" setting to shrink the tubing. This may take a while, as many hair dryers are barely hot enough to cause shrinkage.

GP2D12 cable assembly

One way to do this is to use a small blunt-tipped screwdriver and a paper clip end. If you use a tool that is too sharp it will cut the insulation, which is bad. Add heat shrink if desired. fasten wire to other connector, making sure pin 1 to pin 1 (connectors will be flipped).

GP2D12 placement

Connecting the Servo Motors

Calibrating servos (code download!)

Wheels

Power

On the back of the board the terminal block pins are silkscreened "Vin", "V+", and "GND":

• "V+" is the servo power, which comes directly off the 4AA cells. V+ is the terminal nearest to the corner of the board. Wire the red wire from the 4AA battery pack to the V+ terminal.
• "Vin" is the electronics power, which comes off the 9V battery. This is regulated, so you can put in anywhere between 6V and 16V. Vin is the terminal nearest to the standoff mounting hole. Wire the red wire from the 9V battery to the Vin terminal.
• The middle pin is the common ground, labelled "GND" on the back of the board. Connect the black wires from both the 4AA battery pack and the 9V battery to this pin.

Apply power, look for light

When the 9V battery is connected, move the power switch to the on position. The green LED should light; if it doesn't, check to make sure your 9V battery is good, check to make sure that the 1N4148 diode is inserted in the proper direction, check to make sure the MAX667 is inserted in the proper direction, check to make sure the LED is inserted in the proper direction.

If the red LED is on, your 9V battery is low and isn't providing enough voltage for the Mark III to run. Replace your battery. Note that the LEDs indicate the state of the 9V battery only - they tell you nothing about the 4AA batteries mounted underneath the robot.

Terminal program, communicate with PIC

Connect with HyperTerminal (Windows) or MacTerminal (Macintosh) or xxx (Linux/Unix). (Note: Newer Macs don't have a serial port so they need a USB to serial adapter.) HyperTerminal comes pre-installed on most versions of Windows - it can be found in the "Start" Menu under "Programs/Accessories/Communications". If you don't have HyperTerminal installed for some reason, you can download it from http://www.hilgraeve.com/htpe/index.html.

Terminal settings are 38400 baud, 8 bits, no parity, 1 stop bit. Be sure that you have flow control turned OFF. You cannot communicate with the Mark III board if hardware or software flow control is in use.

When you have HyperTerminal running and the serial cable connected, press the white reset button on the Mark III. This will restart the Mark III and should print the following information in your HyperTerminal window:

    8K PICLOADER v1.1
    Copyright Rick Farmer 1999
    No user code loaded
    Press ? for help
    PIC>

• Wrong type of serial cable. You need a straight-through serial extension cable. The required pinout can be found at http://www.junun.org/MarkIII/Info.jsp?item=22
• Low power. If the red light is on, your 9V battery is low and isn't providing enough voltage for the Mark III to run. Replace your battery.

Self test program which prints values of all sensors

    8K PICLOADER v1.1
    Copyright Rick Farmer 1999
    No user code loaded
    Press ? for help
    PIC>

     Are you sure (Y/N)?

     Erasing

    Ready

    Enter a rev string>

When finished, you will be back to the PICLoader prompt. Typing "Q" at this point will quit the PICLoader and start running the self-test program. Results of the self-test will be displayed in your terminal window.

Line sensors

GP2D12 sensors

If your GP2D12 proximity sensors are not emitting infrared, the most likely cause is a mis-wired cable. See the Assembly Instructions and check to make sure you have made your cable correctly. You can use a DMM to check that power and ground is connected to these sensors. (explain).

Loopback Test

1. Remove the PIC from the socket
2. Jumper pins 37&39 of the 40-pin header together. (These are the two pins next to pins 22&21 of the PIC socket. Pin 39 has a label on the silkscreen next to it, pin 37 is adjacent to it - it is the next one in from the end of the 40-pin header.)
3. Connect a serial cable between your computer and your Mark III
4. Turn on the Mark III power - the green light should go on.
5. Open HyperTerminal and type some characters - they should be echoed on the screen

Note the pins on the 40-pin and 6-pin header are numbered in a zig-zag manner:

 1  2
 3  4
 5  6
 7  8
 9 10
11 12
 :   :
35 36
37 38
39 40

Other Tests

You can check that the reset button works by getting an LED and holding it so that the long lead is in pin 1 of the PIC socket and the short lead is connected to ground. The LED should light up. When you press the reset button, the LED should turn off (this doesn't require any soldering, just bend the leads of the LED so that you can touch them to the right places.)

Visually inspect the soldering on the board to make sure that everything that should be soldered is, and nothing that shouldn't be soldered is soldered. Spend a lot of time looking.

The power regulator, RS232 circuit, the oscillator circuit, and reset circuit are the only things on the board that can cause the PIC to be silent. If all these can be verified to be working, you might have damaged your PIC itself with static electricity, but that is the least common cause of trouble.

Troubleshooting

Where to go for help - mailing list

There are a variety of languages that can be used to program the Mark III. It is suggested that you pick the one most suited to your level of expertise and experience. Sample code for self-test, servo calibration, MiniSumo and Line Following is available for each of the supported languages.

First, a Note About Support

• directions to get started posted here
• sample programs posted here
• the Mark III support forum on Yahoo! Groups at http://www.yahoogroups.com/group/MiniSumoMarkIII/, where your question may already be answered; the Search Archive button is your friend!
• NOTE: you must join the forum in order to post questions or search for answers; it costs nothing, and you can choose at any time whether to receive all messages posted to the forum via email or only read them from the web site
• if you can't find an answer to your question through these three avenues, then post your question to the forum; some other MarkIII owner may know the solution, or one of the MarkIII team members may answer

Supported Languages

Your choice of a programming language depends on your experience, interest level, and budget. There are other languages and programming tools for the PIC16F877 than these; we just aren't currently supporting them.

The supported languages and their advantages are:

• CH Basic (proponent Mark Gross)
  • Using Celestial Horizons' CH Flash Basic Compiler from http://www.celestialhorizons.com/compilers/Flash/flash.htm
  • Celestial Horizons is providing a PIC16F877 version especially for the Mark III Kit
  • The right to obtain a license to this special-edition CH Flash Basic Compiler is included in the Kit when you order
  • Easy to learn
  • Mark's support pages for CH Basic are here: http://thegnar.org/mIII/mIII_tool_chain.htm
• JAL (proponent Brett Nelson)
  • JAL can be found at http://www.voti.nl/jal/
  • Moderately easy to learn; similar to Pascal
  • JAL is free!
• C (proponent James Farwell for CC5X, Pete Skeggs for CCS C)
  • CC5X compiler from http://www.bknd.com/cc5x/index.shtml.
    • Integrates with the MPLAB development environment.
    • There is a free version of CC5X available for download from the above site; the standard edition is $250.
  • CCS C compiler from http://www.ccsinfo.com/picc.shtml.
    • This also integrates with the MPLAB development environment.
    • The PCM compiler costs $125.
  • C is harder to learn than BASIC, but is a great skill to develop; C language compilers are available for virtually every computing platform today
  • C has many of the advantages of assembly language but takes care of the nitty-gritty details for you
• OOPic (proponent Pete Skeggs)
  • Requires separate purchase from http://www.oopic.com/ of an OOPIC chip ($49 gets you a chip, a programming cable, and a prototyping board)
  • Also requires installation of a serial EEPROM in socket U4
  • The OOPic II (http://www.oopic2.com/) is an even more powerful version ($59 at http://www.acroname.com/)
  • Despite the additional cost, provides a powerful object-oriented programming language that lets you bring up a robot prototype very quickly
  • Easy to learn
  • The OOPIC compiler comes with a built-in downloader which requires the use of a parallel port and a Windows PC
  • There are OOPIC accessory boards which can connect to the 40-pin header to add additional functionality to your robot not available on the standard MarkIII accessory boards:
    • http://www.magnevation.com/ - dual 3 amp DC motor driver boards and logic status indicator boards
    • http://www.totalrobots.com/oopic_accessories.htm - lots of cool OOPIC add ons
• PIC assembly (proponent Rick Farmer)
  • Develop using Microchip's MPLAB
  • Requires a lot of effort to learn, but once you do, you really understand how microcontrollers work and how to get them to do what you want
  • It's free!

The MarkIII kit comes with a license for CH Basic, a nice BASIC language compiler specially designed for the PIC. This compiler normally costs $99, but is included in the price of your kit. The maker of the compiler has donated licenses to the project for $10 each, which is a great bargain.

For nonprogrammers, this is the best way to go.

Links to Example Programs

CH Basic examples are here: http://thegnar.org/mIII/markIIICode.htm.

CC5X examples are here: http://groups.yahoo.com/group/MiniSumoMarkIII/files/C-Samples/.

OOPIC examples are here: http://groups.yahoo.com/group/MiniSumoMarkIII/files/OOPIC%20Samples/.

CCS C examples are not ready yet. Sorry.

Neither are JAL examples.

Links to Software Tools

Rick Farmer's PICLoader, a boot loader or ROM Monitor program that comes preprogrammed into the PIC chip included with the Mark III kit. This small program gives the PIC chip enough smarts to talk to a computer and enables it to reprogram the Flash memory in the PIC with new robot programs using only an RS232 serial cable. Without the PICLoader, you would also need to buy a PIC programmer board, such as the Warp-13a from Newfound Electronics (available from the Mark III Store).

Mark Gross's miii_tools (http://thegnar.org/mIII/mIII_tools.zip) include CHPre.exe and mbuild.bat, which help convert the output of CH Basic so that it can be loaded into the PIC using Rick's PICLoader and either HyperTerminal or BotLoader (see below). These are required for all CH Basic users. Power users can hand-edit the CH Basic assembly code and run MPLAB themselves to do this, but even they can benefit by having it done automatically using Mark's tools. Mark's instructions for using them can be found at http://thegnar.org/mIII/mIII_tool_chain.htm.

Pete Skeggs's companion BotLoader and BotLdrCmd are Windows programs that make it easy to send your robot programs to the MarkIII's PICLoader. You can upload programs to the MarkIII using only a simple terminal program such as HyperTerminal (that comes with Windows), but it can be difficult to get all the settings right. BotLoader automatically finds the serial port in use, configures it correctly, and talks to Rick's PICLoader for you. Just browse your PC's hard disk to select your .hex file or type it in to the filename box, then click Go!. BotLdrCmd does the same thing except runs as a command line program for power users to integrate with their make environment. Instructions are here.

Pete Skeggs's CLst2Asm program for enabling the use of CCS C with the version of the PICLoader (1.1) burned into the standard MarkIII PICs. This is useful if you plan to use a variety of languages with the MarkIII. Alternatively, you can reprogram the PICLoader with version 1.3, which automatically works with the hex files output by CCS C, but which makes it hard to use other languages.

Pete Skeggs's Reloader, which (seemingly) does the impossible -- it can reprogram the PICLoader with another version of PICLoader. You can use this program to switch between versions 1.1 and 1.3 of the PICLoader. Instructions are available here.

General Procedure for Programming the Robot

1. write your program's source code (sumo.bsc, firefighter.c, linefollow.jal, etc.) using an editor that either comes with your language tool or with something like Windows' Notepad; start with an example program listed above just to get a feel for the process
2. compile the source code using your language's compiler
3. fix up the output of the compiler (sumo.asm) to be compatible with Rick's PICLoader
4. assemble the fixed up output using MPLAB so that it can be loaded into the PIC (sumo.hex)
5. connect the robot to your PC using a straight-through 9 pin RS-232 serial cable (female on one end, male on the other)
6. load the hex file into the PIC using BotLoader or Hyperterminal or whatever tool you like; NOTE: you must hit enter in Hyperterminal, launch BotLoader or hit the Scan Ports button in BotLoader, within 5 seconds of powering on the robot, or else any existing robot program will be automatically run by Rick's PICLoader.
7. test it out and see if the robot does what you want it to do; if it doesn't, go back to step 1 and try to figure out what went wrong, then fix it and try again

Mark's miii_tools performs steps 3 and 4 for CH Basic users. Steps 3 and 4 are not necessary if you are using CCS C and have switched bootloaders to version 1.3.

Describe functioning of example sumo code, example line following code

MiniSumo

Line Following

Line Maze

Fire Fighting

PDXBOT

Robothon

etc.

Prototype Board

Parts List

Designator	Description
J1	40 pin 100mil pitch dual-row stacking header .435 board separation
J2	6 pin 100 mil pitch dual-row stacking header .435 board separation

Schematic and PCB Layout

• Schematic
• PCB Layout

Assembly instructions

The Prototype Board is meant to stack on top of the Controller Board. Because of this, the two stacking headers that come with the Prototype Board need to have their female ends facing down, so as to mate with the male pins on the Controller Board. Identify the top of the Prototype Board by looking at the silkscreen - the top is labeled "TOP". Insert the male ends of the two header through the bottom of the Prototype Board, so that the male pins point up through the board.

When soldering the headers in place, first tack one pin on each end down with a little bit of solder. Then check to see that the header is seated firmly and flush with the board. Don't complete the soldering until you have it positioned correctly.

Since another mezzanine board may be stacked on top of the Prototype Board, you need to be sure that the solder fillets on the header pins are small. Solder has a tendancy to wick up on the pins - if too much solder is used, then it will make the pins thicker and prevent another board from being mounted on top. If you get too much solder on the pins, you can easily remove it with some soder wick, but it's easier to avoid that problem to begin with.

Sensor Board

Parts List

Designator	Marking	Description
J1		40 pin 100mil pitch dual-row stacking header .435 board separation
J2		6 pin 100 mil pitch dual-row stacking header .435 board separation
J3		100 mil header
J4		100 mil header
J9		8 Pin Header
J10		8x2 Pin Header
J11	White	5-pin 100 mil I²C Connector
RP1	10X1473	9-element common-terminal 47K Ohm resistor network
RP2	8X1223	7-element common-terminal 22K Ohm resistor network
SW1	Red	DIP Switch 6-position
U4		Piezo Buzzer
U6	PCF8574	Remote 8-bit I/O Expander for I²C Bus

Schematic and PCB Layout