Robot Builders Source Book - Gordon McComb Episode 1 Part 4 potx

• Single board computer, also programmed either in assembly language or a high-level language, but generally with more processing power than a microcontroller.. Single board computers SB

102

 http://www.microrobotna.com/

Robot kits, microcontroller boards, and parts for

sumo, soccer, and line-following competition ’bots For

example, the company’s Robo-Lefter is a maze solving

MicroMouse (Its name is derived from the left-turn

maze-solving algorithm it uses.) The products are

available through distributors or directly from

Microbot NA

x 

http://www.robofesta-europe.org/

RoboFesta-Europe is part of an international

move-ment to promote interest throughout Europe in

sci-ence and technology, including robotics Sponsors

Olympics-style competition events

See also the international RoboFesta page:

http://www.robofesta.net/

RoboFesta-International 203952

http://www.robofesta.net/

RoboFesta is an international movement to promote

interest throughout the world in science and

technol-ogy, including robotics Sponsors Olympics-style

com-petition events Web page in Japanese, English, and

Autonomous mobile robots compete against one

another to capture a flag See also:

Robotag.com Web site.

http://www.dreamdroid.com/talentshow.htm

A regular talent show put on by the Robotics Society ofSouthern California; judging is by software, hardware,and how good your ’bot looks in a swimsuit

http://www.robotag.comTag-playing entrant Plenty of design photos

Trinity College Fire-Fighting

http://www.trincoll.edu/events/robot/

World-famous firefighting contest Robots roll or walkthrough a scaled-down model of a house looking for acandle to extinguish Harder than it sounds

competitions-OTHER 103

Walking Machine Challenge 202561

http://www.sae.org/students/walking.htm

The Society of Automotive Engineers sponsors a

chal-lenge in college-level engineering to design, build, and

test a walking machine with a self-contained power

source Many of the resulting designs are quite

sophis-ticated

Western Canadian Robot Games 202093

http://www.robotgames.com/

The Western Canadian Robot Games is one of the

old-est robot competitions, with events that include sumo

wresting, something called atomic hockey, a hallway

navigation game for walking robots, and a series of

chal-lenges specially designed for BEAM robots The

compe-titions are held annually in Alberta, Canada

vides a view of the game field, and this view is cally interpolated to remotely command the players.The RoboCup soccer competition is the most famous,and there are local versions of it for those who cannottravel to Japan, where the main event is staged.Soccer is one form of robot game that involves balls.Other forms include volleyball and ball collecting

Canada First is a team-based robotics competition sored by various Canadian companies to motivate stu-dents in the fields of math, science, and technology.The competitions generally involve soccer and ball han-dling of some type

spon-Web site is in English and French

Web site is in Japanese and English

col-

Web site for the Western Canadian Robot Games.

qr Competitions-Soccer

& Ball Playing

Robotic soccer is played either by two robots against

one another, or one team of robots against another

This form of robot competition is among the most

chal-lenging, especially for multirobot teams In the

multi-ple-robot version of the game, each robot plays a

cer-tain position on the team and is programmed

accordingly The robots must communicate with one

another in order to play successfully In some soccer

tournaments, an overhead machine vision system

pro-competitions-soccer & ball playing

104

KISS Institute for Practical

http://www.kipr.org/

In the words ofthe Web site: “KISS Institute for Practical

Robotics (KIPR) is a private non-profit

community-based organization that works with all ages to provide

improved learning and skills development through the

application oftechnology, particularly robotics We do

this primarily by providing supplementary,

extra-curric-ular and professional development classes and activities

KISS Institute’s activities began in 1993.”

KIPR also sponsors the annual Bot Ball tournament for

middle and high school students

http://www.robocup.org/

RoboCup is an international project to promote the fields

of artificial intelligence and robotics This is accomplished

with soccer competitions-two teams of robots square off

against one another and play a game of soccer without

human intervention RoboCup is held annually in Japan

A game of robot volleyball between teams of two robots,which were built using LEGO Mindstorms

qr Competitions-Sumo

Robot sumo involves two contestants on a round ing mat The object is for one contestant to push itsopponent off the mat before it gets pushed out In allbut a few cases, the robot fighters are autonomous andare not controlled remotely by a human operator.The playing mat is typically 6 feet in diameter and ispainted black A white stripe is painted near the outsiderim of the mat and is used by the robot to help it deter-mine the boundary of the playing field

play-Sumo competitions are separated into weight classes.All robots within a class must weigh less than the stipu-lated amount, such as 2, 10, or 20 pounds Noweaponry is typically allowed in a sumo competition—it’s all about pushing

CIRC Autonomous Sumo Robot

Web site for RoboCup, held yearly in Japan.

http://www.robocupjunior.org.au/

RoboCup Junior, based in Melbourne, Australia, is for

the design, construction, and competition of

autonomous soccer-playing robots The competitions

are intended for school-age students

One of the biggest American sumo competitions.

Robot sumo, that is The sponsor of the competition isSine Robotics:

http://www.sinerobotics.com/

OCAD Sumo Robot Challenge 203347http://www.student.ocad.on.ca/info/sumo/

Bashing/crashing/smashing robots sponsored by theOntario College of Art & Design

Explora-

Tips for Effective Sumo Robot Wrestling

If you've ever watched a real sumo-wrestling match, then you know that at least part ofthe sport relies on weight and girth Same with sumo robot wrestling, where the aim is topush your opponent outside the game field—usually a round, black circle All things con-sidered, a heavier robot will push a lighter robot aside, but there is more science involvedthan you might think

• In most competitions, the advantage of weight is minimized by putting contestants intovarious classes For the most part, you'll want your robot to be on the heavier side ofits class, for any advantage that might give you

• Still, bear in mind that the heavier the robot, the harder it might be for its motors to vide adequate speed and torque Don't blindly sacrifice agility for weight A fast-movingrobot can more readily get out of trouble or position itself for a sideways push

pro-• Wheel traction is critical Be sure to read the rules for the competition, as you may berestricted on the size, material, and thickness of the wheels you use Soft rubber pro-vides better traction and helps prevent your opponent from pushing you off the play

field Wider wheels offer increased surface area and therefore better traction

• A low center of gravity ensures your robot won't be easily turned over A low, squat

robot is usually the best design

• Many sumo robots use a scoop-like shovel at the front to partially lift their competitorsoff the play field Once lifted, robots are easy prey See if the competition rules allow for

a shovel (most do not permit a weapon)

106

V Computers

Listings in this section deal with computers for robot

control, as well as computer interfacing and data

acqui-sition The emphasis is on small computers, particularly

those that are self-contained and can be powered by a

single 5- or 12-volt DC source

V Computers-Data

Acquisition

Data acquisition involves circuitry that converts an

ana-log signal, such as temperature or vibration, to digital

form so that it can be processed by a computer This

section lists data acquisition boards for PC-compatible

computers as well as general-purpose data acquisition

modules Data acquisition modules typically provide

their data through a standard interface, such as PC

par-allel port, RS-232, or USB

DATAQ Instruments, Inc 202667

Dataq makes and sells data acquisition hardware and

accessories, data acquisition software,

signal-condition-ing components, and data acquisition starter kits (some

low-cost bargains here)

• Sampling A/D converters

• Data acquisition boardsDatasheets available for the products in Adobe AcrobatPDF Web site is in English and Japanese

x V

3112 S Independence Ct

Lakewood, CO 80227-4445USA

LabJack U12 Photo LabJack Corp.

Copyright 2003 by Gordon McComb Click Here for Terms of Use.

computers-data acquisition 107

Giving Your ‘Bot a Brain

Even the Scarecrow from The Wizard of Oz wanted a brain You want your robot to be

at least as smart as the Scarecrow, right? You can be your own wizard of Emerald City

by giving out brains to your robotic creations Instead of some phoney-baloney

diploma, the brains you give your robots will be electronic in nature The only trick is—which electronics?

Noncomputer Electronic Components

Noncomputer discrete components—transistors, resistors, capacitors, and integrated cuits—can be used to control a robot Such robots typically are "hard-wired" to performsome task, such as follow a line or seek out light BEAM robots are a good example ofmachines that have noncomputer brains: No number crunching is going on in their elec-tronics Rather, simple electronic circuits compel the robot to move

cir-A popular design uses a 555 timer IC to control a motor Separate 555 chips control

each motor of a two-wheeled robot The 555 timer outputs a series of short pulses, andthe duration of these pulses determines the speed of the motor If one motor goes a littleslower than the other, the robot will move in wide, sweeping arcs Add some bumper

switches to the robot to back it up and another 555 to time how long the robot reversesdirection, and the machine will do a remarkable job of navigating around a room

Watching the robot, you'd think the thing were controlled by a computer, but its "brain"

is a simple collection of parts you can buy at Radio Shack (If you're interested, the design

for such a robot can be found in the book, Mobile Robots: From Inspiration to

Implementation, among other sources.)

Computers and Microcontrollers

As attractive as noncomputer brains are, they are basically "hard-wired" as circuitry, andmaking changes to them requires lots of work A robot controlled by a computer can be

“rewired” simply by changing the software running on the computer

There is an almost endless variety of computers that be used as robot brains The

three most common are:

• Microcontroller, programmed either in assembly language or a high-level language

such as Basic or C The LEGO Mindstorms RCX is a good example of a robot run from

a microcontroller Microcontrollers are available in 4-, 8-, 16-, and 32-bit versions (plus

a few others, for special purposes) The Basic Stamp, PICmicro, AVR, OOPic, and

BasicX are good examples of microcontrollers commonly used in amateur robotics

• Single board computer, also programmed either in assembly language or a high-level

language, but generally with more processing power than a microcontroller Single

board computers (SBCs) are a lot like "junior PCs," but on a single circuit board In fact,many SBCs are IBM PC-compatible and use Intel microprocessors capable of runningany Intel-based program, including the MS-DOS operating system A common SBC

form factor is PC/104, which gets its name from "Personal Computer" (originally of IBMfame) and the number of pins (104) used to connect two or more PC/104-compatibleboards together

• Personal computer, such as a PC compatible or an Apple Macintosh, or even an older

model such as the venerable Commodore 64 A good option for robotics is a patible laptop, particularly the older monochrome models that required less battery

PC-com-power They're also fairly inexpensive on the used market

Prairie Digital sells I/O and interface boards:

• General-purpose data acquisition system for PCs

• 8-bit analog-to-digital converter

• 12-bit analog-to-digital converter

• Serial port data acquisition and control module

• Low-cost 5 1/2-digit A/D with RS-232 serial control

• Relay board

x 

V Computers-I/O

I/O stands for input/output, circuitry designed to

interface a computer to external circuitry On a PC,

I/O is used to connect the computer to a printer, for

example The I/O performs important functions of

conditioning the data and acting as a barrier to

prob-lems caused by the external device The idea here is

that it’s cheaper to replace an I/O board or module

than the complete computer

The I/O listed in this section is particularly suited for

robotics and other embedded applications Depending

on the configuration, I/O can be used with single

board computers (SBCs) or with microcontrollers

Examples of I/O modules include relay bays (the

com-puter activates the relays from program control),

self-contained Web servers, and generic interfaces to per motor or H-bridge drivers

step-SEE ALSO:

Computers-Single Board Computers:

Something to connect the I/O to

Internet-Circuit Examples: Plans for made I/O

home-LEGO-Mindstorms: Ideas for I/O expansion forthe Mindstorms robot

Microcontrollers-Hardware: Using amicrocontroller instead of an SBC

895 Commercial St

Ste.700Palo Alto, CA 94303USA

(650) 493-8700

 (650) 493-2200

 salesinfo@activewireinc.com

 http://www.activewireinc.com/Manufacturers andsellers of ActiveWire-USB, a low-cost module designed

to provide programmable I/O pins that can interface

to anything, via a USB serial port on a PC orMacintosh Programming examples are provided forMacintosh, Win95/98/2000/ME, Linux, FreeBSD, andLabView

The company offers add-on interfacing modules,including:

• Motor control board, for controlling up to six small

DC motors (maximum 600mA to 1A)

Products includes USB converters

Movers and Shakers

Steve Mann

http://www.eecg.toronto.edu/~mann/

Professor Steve Mann, of the University of Toronto,literally wears his work He’s widely known as the firstperson to actively and continually wear implantedelectronic gizmos—the “Six-Million-Dollar Teacher.” His research involves the “wearable computer,” a sili-con brain that assists people in their everyday lives,possibly (at some point in the future) becoming a

part of them Of course, shades of The Borg and a lot

of other sci-fi themes, but Professor Mann doesn’tseem to have domination of the galaxy on his mind

computers-i/o 109

Athena Microsystem Solutions 202522

10624 Rockley Rd

Houston, TX 77099USA

periph-x 

• LCD character display module

• Opto-isolator module, for connecting to relays,

H-bridges, SCRs, and other high-current devices

x 

Model uIO Input output expansion board.

Photo JKmicrosystems, Inc.

110

Of Inputs and Outputs

Number Five (from the movie Short Circuit) was always shouting about "more input."Robots need both input and output—ways to get data from the outside world (input), andways to control external devices, like motors (output)

There are several specialized forms of I/O found on computers and microcontrollersthat robots can use Many are proprietary to a given circuit architecture: Microcontrollersfrom National may favor one approach; chips from Philips may favor another In the end,many do similar jobs

Serial Communications

I2C—Inter-Integrated Circuit, a two-wire serial network protocol used by Philips to allow

integrated circuits to communicate with one another With I2C you can install two ormore microcontrollers in a robot and have them communicate with one another OneI2C-equipped microcontroller may be the "master," while the others are used for spe-cial tasks, such as interrogating sensors or operating the motors

Microwire—A serial synchronous serial communications protocol used in National

Semiconductor products, and popular for use with the PICMicro line of microcontrollersfrom Microchip Technologies Most Microwire-compatible components are used forinterfacing with microcontroller/microprocessor support electronics, such as memoryand analog-to-digital converters

SCI—Serial communications interface, an enhanced version of the UART, detailed later SPI—Serial peripheral interface standard used by Motorola and others to communicate

between devices Like Microwire, SPI is most often used for interfacing with troller/microprocessor support electronics, especially outboard EEPROM memory

microcon-Synchronous serial port—Data is transmitted one bit at a time, using two wires One wire

contains the transmitted data, and the other wire contains a clock signal The clockserves as a timing reference for the transmitted data Note that this is different fromasynchronous serial communication (see the following), which does not use a separateclock signal

UART—Universal asynchronous receiver transmitter, used for serial communications

between devices, such as your PC and the robot's computer or microcontroller

Asynchronous means that there is no separate synchronizing system for the data Instead, the data itself is embedded with special bits (called start and stop bits) to

ensure proper flow The USART (Universal Synchronous/Asynchronous ReceiverTransmitter) can be used in either asynchronous or synchronous mode, providing forfaster throughput of data

Data Conversion

ADC—Analog-to-digital conversion transforms analog (linear) voltage changes to binary

(digital) ADCs can be outboard, contained in a single integrated circuit, or included aspart of a microcontroller Multiple inputs on an ADC chip allow a single IC to be usedwith several inputs (4, 8, and 16 input ADCs are common)

DAC—Digital-to-analog conversion transforms binary (digital) signals to analog (linear)

voltage levels DACs are not as commonly employed in robots; rather they are monly found on such devices as compact disc players

Pulse and Frequency Management

Input capture—An input to a timer that determines the frequency of an incoming digital

signal With this information, for example, a robot could differentiate between inputs,such as two different locator beacons in a room Input capture is similar in concept to atunable radio

PWM—Pulse width modulator, a digital output that has a square wave of varying duty

cycle (e.g., the "on" time for the waveform is longer or shorter than the "off" time)

Often used with a simple resistor and capacitor to approximate digital-to-analog version, to create sound output, and to control the speed of a DC motor

con-Pulse accumulator—An automatic counter that counts the number of pulses received on

an input over x period of time The pulse accumulator is part of the architecture of the

microprocessor or microcontroller and can be programmed autonomously; that is, theaccumulator can be collecting data even when the rest of the microprocessor/micro-controller is busy running some other program

Special Functions

Hardware interrupts—Interrupts are special input that provides a means to get the

atten-tion of a microprocessor or microcontroller When the interrupt is triggered, the processor can temporarily suspend normal program execution and run a special sub-program

micro-Comparator—An input that can compare a voltage level against a reference; the value of

the input is then lower (0) or higher (1) than the reference Comparators are most oftenused as simple analog-to-digital converters where HIGH and LOW are represented bysomething other than the normal voltage levels (which can vary, depending on the kind

of logic circuit used) For example, a comparator may trigger HIGH at 2.7 volts

Normally, a digital circuit will treat any voltage over about 0.5 or 1 volt as HIGH; anythingelse is considered LOW

Analog/mixed-signal (A/MS)—Inputs (and often outputs) that can handle analog or digital

signals, under software guidance Many microcontrollers are designed to handle bothanalog and digital signals on the same chip, and to even mix -and match analog/digital

on the same pins of the device

External reset—An input that resets the computer or microcontroller so that it clears any

data in RAM and restarts its program (the program stored in EEPROM or elsewhere isnot erased)

Switch debouncer—Cleans up the signal transition when a mechanical switch (push

but-ton, mercury, magnetic reed, etc.) opens or closes Without a debouncer, the controlelectronics may see numerous signal transitions and could interpret each one as a sep-arate switch state With the debouncer, the control electronics sees just a single transi-tion

Input pullup—Pullup resistors (5 to 10K) are required for many kinds of inputs to control

electronics If the source of the input is not actively generating a signal, the input could

"float" and therefore confuse the robot's brain The pullup resistors, which can be builtinto a microcontroller and activated via software, prevent this floating from occurring

Siteplayer is a Web server the size of a postage stamp.

Really, a 1-inch-square postage stamp! The Siteplayer

module has a built-in Web server and Ethernet adapter,

allowing it to be used on any TCP/IP connection

SitePlayer sports eight I/O pins, which can be

individu-ally programmed via Web commands

The use in robotics is obvious, including remote

con-trol of a robot connected via the Internet Add a video

camera, and you-or anyone else-can control a robot

from around the globe

up to 32 modules (hence, peripherals) on the same

RS-232 cable connected to a host PC Reasonable prices

• Solid state relay module

• Analog input module

• Analog output module

• Stepper motor driver

SitePlayer, on the SitePlayer development kit

board Photo NetMedia, Inc.

Analog to digital interface Photo Weeder Technologies.

Winford produces computer I/O cards and accessories

for the PC Their CRD155B is an 8-bit ISA card that

pro-vides 24 digital I/O lines The CRD155B card can be

programmed and controlled by using Winford

Engineering’s Portal API

x V

V Computers-Single Board

Computers

The term single board computer is a holdover from

days when most computers consisted of a main board

(called the motherboard) and additional peripheral

boards (called daughter cards) for extra features such

as I/O of disk drive interface Today, even desktop PCs

use a single printed circuit board, all basic functions are

built in-including I/O, disk interface, sound, and

dis-play adapter

Today the term single board computer has evolved to

mean a compact computer board, especially one that

can be powered by a single 5- or 12-volt voltage source

and that is intended primarily for use as a controller in

a piece of hardware-a so-called embedded application

Most of the single board computers (SBCs) in this

sec-tion are smaller than 4 inches square

SEE ALSO:

Microcontrollers-Hardware: Computers

on a single chip

Programming-Languages: Programming

lan-guages, such as C and Basic, for computers

Programming Platforms & Software:

Manufacturer and distributor of PC/104 modules,

LPX-size SBCs, and media SBCs (compact computers

designed for media applications) Offices in the U.S.,

Korea, and Germany

x 

4411 Morena Blvd

Ste 230San Diego, CA 92117USA

com-xAll Industrial Systems, Inc 202889

672 Still Meadows Circle EastPalm Harbor, FL 34683USA

x Arcom Control Systems, Inc 202890

7500 West 161st St

Stilwell, KS 66085USA

x Axiom Manufacturing, Inc 202891

2813 Industrial Ln

Garland, TX 75041USA

computers-i/o 113

(972) 926-9303

 (972) 926-6063

 sales@axman.com

 http://www.axman.com/

In the words of the Web site: “Axiom Manufacturing is a

diverse microcontroller company specializing in single

board computers, embedded controllers, custom

design, and manufacturing solutions.”

Products include single board computers based on the

Motorola 68HC11 and 68HC12 microcontrollers,

80CXX microprocessor, MPC555 PowerPC, and

Makers of PC/104 form-factor single board computers

with analog I/O and serial ports

Manufacturer of PC-compatible SBCs,; SBC

microcon-trollers, embedded servers, microprocessor trainers,

x 

3201 Highgate Ln

St Charles, MO 63301USA

x V

1403 Fifth St

Ste DDavis, CA 95616USA

 http://www.jkmicro.com/

JKmicrosystems makes single board computers,

periph-eral boards (A/D converter, I/O, relay), keypads, and

Embedded computers, including 386 XT Size 386SX-40

single board computers

Micromint is a leading supplier of single board

comput-ers and industrial embedded controllcomput-ers Their

prod-ucts include:

• Domino (80C52 with BASIC)

• PicStic micro modules

• Answer MAN (network-based data acquisition)

• TI01 (based on Polaroid ranger)

• Embedded modem module

• 80C52-BASIC chip

• Power line interface for X-10

x V

computers-single board computers 115

Model 2400EMM data modem Photo Micromint, Inc.

http://www.pc104.org/

According to the site, “We are a Consortium of over 100members worldwide who have joined together to dis-seminate information about PC/104 and to provide aliaison function between PC/104 and standard organi-zations.” Fair enough



computers-single board computers

116

Single Board Computers

Not long ago, the notion of a computer on a single, small circuit board was science tion Now, they're so plentiful you'll find them at hundreds of sources In this book we pro-vide a handful of sources to get you started; there are many others, particularly those thatspecialize in computers for particular applications, such as controlling an elevator, operat-ing a construction crane, or adjusting the fuel-air mixture in your car's engine

fic-These applications are often referred to as embedded, because a computer is

"embedded" as part of the overall functionality of the device For this reason, single board computers are almost universally used for some embedded application, though they are

also of premier interest to robot builders, because of their power, small size, and lowenergy requirements

With the proliferation of single board computers (or SBCs) has also come a dizzying array of types, sizes, and styles Fortunately, a form -factor known as PC/104 provides a

handy standard that makes it easier to select and use SBCs and peripherals, even fromamong different manufacturers

PC/104 boards measure about 3.5 inches square (specifically 90 by 96mm) The "104"comes from the number of interconnection pins used to stack the boards together Thisstacking allows you to add to a PC/104 SBC without using back planes (like in a PC-com-patible computer) or connectors and cables There are both 8- and 16-bit versions for thePC/104, and there are different options within the specification

More information on the PC/104 standard can be found at the PC/104 Consortium at:

http://www.pc104.org

While PC/104 is perhaps the most common standard form factor for SBCs, it's not theonly one A fairly popular SBC is the PCI or ISA "daughter card," designed to fit into anexpansion slot of a PC-compatible (PCI and ISA are connector standards; PCI is the cur-rent type used in PCs, and ISA is the older 8- and 16-bit style) Though intended to beused inside another computer, daughter card SBCs are in fact independent computers.They are for applications that require extra processing power, when you don't want to taxthe main processor of the computer

Should You Use a PC as a Robot Brain?

The average PC may be desk-bound, but that doesn't mean you can't mount it on yourrobot and use it in a portable environment That said, you may not want to use the com-puter for your robot's brain Some PCs are more suited for conversion to mobile robotuse than others Consider the following qualities of a computer pressed into service asthe brain of an untethered mobile robot:

• Small size In this case, small means that the computer can fit in or on your robot A

computer small enough for one robot may be a King Kong to another Generally ing, however, a computer larger than about 12 inches by 12 inches is too big for anyreasonably sized 'bot

speak-• Standard power supply requirements Some computers need only a few power supply

voltages, most often +5, and sometimes +12 A few, like the IBM PC-compatible,

requires* negative reference voltages of -12 and -5 (*Required is a nebulous thing:

Some PC-compatible motherboards will still function if the -12 and -5 voltages areabsent, though functions such as RS-232 serial may not operate correctly.)

• Accessibility to the microprocessor system bus or an input/output port The computer

won't do you much good if you can't access the data, address, and control lines The IBM

PC architecture provides for ready expansion using "daughter" cards that connect to themotherboard It also supports a variety of standard I/O ports, including parallel and serial

Makers of single board computers and microcontroller

boards, many using the TICKit interpreter engine, said

to offer faster processing than the Basic Stamp

Products include:

• TICKit 63 processor IC

• TICKit 63 computer module

• RSB509b serial data buffer IC

• TICKit 63 single board computer

x 

R.L.C Enterprises, Inc 202893

2985 Theatre Dr

Paso Robles, CA 93446USA

computers-single board computers 117

• Uni- or bidirectional parallel port If the computer lacks

access to the system bus, or if you elect not to use that

bus, you should have a built-in parallel port This allows

you to use 8-bit data to control functionality of your robot

The Commodore 64, no longer made but still available in

the used market, supports a fully bidirectional parallel

port

• Programmability You must be able to program the

com-puter using either assembly language or a higher-level

language such as Basic, C, Logo, or Pascal

• Mass storage capability You need a way to store the

programs you write for your robot, or every time the

power is removed from the computer, you'll have to rekey

the program back in (Recall that microcontrollers and SBCs equipped with Flash or

EEPROM memory retain their programs even when power is removed.) Floppy disks orsmall, low-power hard disk drives are possible contenders here

• Availability of technical details You can't tinker with a computer unless you have a full

technical reference manual The reference manual should include full schematics, or atthe very least, a pinout of all the ports and expansion slots Some manufacturers do notpublish technical details on their computers, but the information is usually available fromindependent book publishers Visit the library or a bookstore to find a reference manualfor your computer

Using an AC Inverter for a PC Power Source

You've read elsewhere in this section about using a PC motherboard as the brains for

your 'bot They're cheap, reliable, and very competent computers, but a disadvantage istheir power requirements Many require different voltages, namely +/-5 and +/-12 volts.Another option is to power your robot from a 12-volt battery connected to an AC

inverter These are available at auto supply stores and many department stores that carryautomotive supplies They are designed to work with the 12-volt system of a car and canprovide enough operating juice to power the typical later-model PC (older models mayuse very power-hungry components) The PC plugs into the inverter as if it were a walloutlet

AC inverters are available in different wattages As you might imagine, the higher thewattage, the more expensive the inverter You do not need a 3,000-watt inverter; try a400- to 800-watt version first

An old 486-class motherboard One possible use for this relic

is as a robot brain.

(805) 239-9737

 (805) 239-9736

 http://www.rlc.com/

Makers of embedded single board PCs with the

Windows CE operating system, touch screens, and I/O

interfaces built in Intended mainly for original

equip-ment manufacturers (OEMs) purchases, but sells in

Tern provides 16- and 32-bit microcontrollers

(Intel-based or NEC V25) and software development

pack-ages for C, C++, and x86 assembly language

on the PIC16C62, PIC16C74, 80C188EB, and 68332Gprocessors, and come in a variety of models depending

on the system level resources (such as memory andports) that your project requires.”

Product line highlights include:

• Single-tasking and multitasking BASIC

• A/D interface

• TTL digital I/O

• Optically isolated inputs, relay outputs

• D/A output amplifiers

x 

6 Way Rd

Middlefield, CT 06455USA

x $ V

Krefelder Str 147

52070 AachenGermany

computers-single board computers 119

Win Systems is a manufacturer of single board

comput-ers, PC/104, PC/104-Plus, and STD bus products

Single board computers (with or without built-in

Ether-net connectivity), I/O boards, embedded control

sys-tems, C compiler engineered for Z-World embedded

products

x V

357 Inverness Dr SouthSte C

Englewood, CO 80112USA

@ Distributor/Wholesaler

In the retail chain, a distributor is a company or other

organization that purchases specialized product for

resale, either to other distributors, retailers, or end

users Manufacturers often prefer working strictly

through a distributor for cost reasons: it's cheaper to

sell their product to a small handful of “go-betweeners”

(other distributors or retailers) than thousands-if not

tens of thousands-of end users

Wholesalers serve a similar purpose as distributors, but

the term is meant to be restricted to those who buy and

sell in quantities When buying through a distributor,

you can often purchase in single quantities (though

minimum order amounts and extra handling charges

may apply) Wholesalers want you to buy in bulk, and

they offer discounts to make that a more attractive

option

The companies listed in the Distributor/Wholesaler

sections run the gamut from high-quantity wholesalers

to what are in effect retail sales of individual

compo-nents Most of the distributors listed are for industrial

electronics and may serve the needs of garage shop

tin-kers, schools, and companies

It's important to note that the Internet is changing the

way manufacturers view their distributor/customer

relationships Thanks to e-commerce and online

buy-ing, the costs of servicing customers are reduced

greatly, allowing more and more manufacturers to deal

directly with the buying public In some cases, such

direct sales are cheaper than going through a

distribu-tor; in most instances, buying online direct from the

manufacturer is for convenience only

@

Distributor/Wholesaler-Industrial Electronics

Distributors and wholesalers of industrial electronics

supply a much broader range of product than the

aver-age electronics retailer The product may also be

avail-able in larger quantities (possibly representing a

sav-ings, if you need that many), with greater numbers of

options and choices Most of the companies listed in

this section sell directly, either online or in retail

estab-lishments Minimum order amounts may apply, so

you'll want to save up your orders to avoid any

addi-tional fees

Industrial electronics distributors and wholesalers areused to dealing with purchasing departments of compa-nies, where X part is specified by the customer, and Xpart is shipped For this reason, most distributors andwholesalers publish a “line card” showing either theproducts they carry or the brands they represent (orboth) If online ordering is not offered, you will need tolocate copies of catalogs from various manufacturersand order by part number

http://www.activestores.com/

Future Electronics—

http://www.futureelectronics.com/

Future Active—http://www.future-active.com/Future Global

Copyright 2003 by Gordon McComb Click Here for Terms of Use.

Allied Electronics is a prime source for all electronics

(components, chemicals, tools, you name it), in single

or multiple quantities Their prices are often lower

than the competition's Do note the minimum order

($50 at the time of this writing) The online catalog is

database driven and is searchable

Datasheets are provided for many components, even

fairly obscure semiconductors You need Adobe

Acrobat Reader to access the datasheets or catalog-page

VAppleton Electronic Distributors, Inc 203603

205 W Wisconsin Ave

Appleton, WI 54911USA

General electronics and tools

Philmore & Datak

http://www.philmore-datak.com/

Wide range of active and passive components; nectors, cables, switches, tools, accessories; kitsLED dice, RF transmitter, PIR movement detector

con-Polykom

http://www.polykom.com/

Industrial electronics supplier in Australia

Reptron Electronics, Inc.

http://www.reptron.com/

45,000 electronic component products from over

60 vendors