Robot Builders Source Book - Gordon McComb Episode 2 Part 8 pps

The company also sells a miniature wireless camera for use Google.com Search Phrases for Video and Robotics Try these for locating more information about using cameras in robotics: intit

video-cameras 663

 sales@newtonlabs.com

 http://www.newtonlabs.com/

High-end machine vision

In the words of the Web site, “Newton Labs develops

and manufactures full turnkey machine vision systems,

specializing in high speed and high resolution Newton

also manufactures robotics systems, diode laser

prod-ucts, and academic/research products Newton Labs

powerful, easy to use, and industrially rugged systems

provide solutions for wide ranging vision and robotics

applications for virtually every industry.”

555-A West Lambert Rd.

One Technology Place Homer, NY 13077 USA

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1105 8th St East Saskatoon, Saskatchewan S7H 0S3

Better Pictures with Better Lenses

If you’re interested in exploring vision systems for your robot creations, be sure to sider the quality of the lens (some solid-state imagers don’t even come with a lens; youmust add your own) Many of the smallest solid-state cameras were designed as elec-tronic peepholes for doors and so have a very wide field of view—almost a “fisheye”

con-appearance—to see as much outside as possible

With wide views comes distortion of the image That can make it hard to process theimage to detect shapes and objects For robotics work, you’ll want the best lens you canafford, preferably one that provides a normal field of view This will reduce the so-calledbarrel distortion common in wide-angle lenses

The least expensive solid-state cameras come with a nonremovable lens, so you getwhat you get The lens is interchangeable on the better units A few are designed to workwith standard C-mount lenses, which any CCTV reseller can provide

Better Eyes to See You With

Most ‘bot eyes are far simpler than the ocular sensors we humans have, yet they functionquite admirably despite their lack of complexity Here are the most common devices usedfor robot eyes

• Photoresistors, typically a cadmium sulfide (Cds) cell (often referred to simply as a tocell) A Cds cell acts like a light-dependent resistor: The resistance of the cell varies

pho-depending on the intensity of the light striking it When no light strikes the cell, thedevice exhibits very high resistance, typically in the high hundreds of K ohms, or evenmegohms Light reduces the resistance, usually significantly (a few hundreds or thou-sands of ohms) Cds cells are very easy to interface to other electronics, but they aresomewhat slow reacting and are unable to discern when light flashes more than 20 or

30 times per second This trait actually comes in handy, as it means Cds cells basicallyignore the on/off flashes of AC-operated lights

• Phototransistors are very much like regular transistors, with their metal or plastic top

removed A glass or plastic cover protects the delicate transistor substrate inside.Unlike Cds cells, phototransistors are very quick acting, able to sense tens of thou-sands of flashes of light per second The output of a phototransistor is not “linear”; that

is, there is a disproportionate change in the output of a phototransistor as more andmore light strikes it A phototransistor can become easily “swamped” with too muchlight Even as more light shines on the device, the phototransistor is not able to detectany more change

• Photodiodes are the simpler diode versions of phototransistors Like phototransistors,

they are made with a glass or plastic cover to protect the semiconductor materialinside them And like phototransistors, photodiodes are very fast acting and canbecome “swamped” when exposed to a certain threshold of light One common char-acteristic of most photodiodes is that their output is rather low, even when fully

exposed to bright light This means that to be effective, the output of the photodiodemust usually be connected to a small amplifier of some type

• Pyroelectric sensors—commonly referred to as PIR, for “passive infrared”—see by

detecting changes in heat They can be purchased new or salvaged from an existingmotion detector The most common use of pyroelectric infrared (or PIR) sensors is inburglar alarms and motion detectors Because PIR sensors see only objects that move,they can be used to distinguish between animate and inanimate objects

• Ultrasonic sensors send out a beam of sound, and then wait for the return echo The

difference in time between the burst of sound and its return echo indicates distance Bytaking many measurements while slowly moving the ultrasonic sensor, it’s possible forthe robot to “map” the topography of its immediate environment

• Radar is like ultrasonics, but it uses radio waves instead of sound The advantage of

radar is that the resolution—the ability to determine objects of small size—is far betterthan ultrasonics The disadvantage is that workable radar detectors for robotics arequite expensive

• Video cameras can be directly connected to computers, and the image they receive

can be analyzed by software They are the most like “real” eyes, and while video eras are now relatively inexpensive and produce excellent detail, the limitation is in thesoftware It’s not an easy task to break down and analyze a moving scene in an unpre-dictable environment, particularly in real time No doubt this area of robotics willundergo massive improvements in the years to come and will someday give the abilityfor robots to see just as humans do

cam-video-cameras 665

 ufoman@plantraco.com

 http://www.plantraco.com/

Sellers of upscale radio-controlled toys, including

blimps and little tracked vehicles Their Desktop Rover

tracked vehicle can be controlled via a handheld

remote or by software running on your computer The

company also sells a miniature wireless camera for use

Google.com Search Phrases for Video and Robotics

Try these for locating more information about using cameras in robotics:

intitle:”basic stamp” camera

intitle:AVR camera

intitle:microcontroller camera

intitle:PIC camera

video robot camera

vision robot camera

webcam robot OR roboticsrobot vision mapping OR map

Polaris Industries miniature board camera.

Photo Polaris Industries.

Polaris Industries micro “lipstick”

camera Photo Polaris Industries.

 (800) 335-9777

 http://www.supercircuits.com/

Super Circuits sells wired and wireless video cameras, miniature (including the size of a shirt button) cam- eras, and video transmitters and receivers Good stuff at reasonable prices.

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123 N.E Seventh Ave.

Portland, OR 97293-0040 USA

Alternative Sources for Video Cameras

You don’t need to buy a specialty solid-state video camera to give eyes to your robot

There are a few alternative sources for low-cost imagers:

• Hacked wireless security camera You’ve seen ads for wireless security cameras you

can “put anywhere.” The camera, which operates at 9 to 12 volts DC, transmits its nal in the 2.4-gigahertz range You need a video receiver to pick up the signal Qualityvaries greatly, especially under low-light condition Test a sample camera first beforetaking it apart And be sure to turn off any microwave ovens that are operating nearby,

sig-as they emit a signal close to the operating frequency of these camersig-as

• Game Boy camera These were available for a time—but are now discontinued—for the

venerable Nintendo Game Boy handheld game machine You can still find them at

swap meets, used computer stores, and at online auctions, such as eBay (the GameBoy device is not needed to hack the camera) The resolution is fairly low—128 by 123pixels—but the camera is cheap and worth the hacking effort Here are two sources forhacking the camera:

http://pages.zoom.co.uk/andyc/camera.htm.

http://homepages.paradise.net.nz/~vkemp/gbcam.htm

Google.com search: +gameboy +camera hacking

• Older model digital still cameras Digital cameras get better all the time Ones with USB

or serial interfaces to transfer the pictures to a PC are good candidates for hacking

• USB serial Webcams Many of the latest Webcams are cheap and are inherently digital,

as they connect to the PC (or Macintosh or whatever) via a USB serial link With somework, you may be able to hack a Webcam for robotics But take note: While the datamay be transferred via USB, the format of that data is likely propriety and varies fromone manufacturer to the other Some Webcam makers provide a software developer’skit or publish the data format specifications for their products, but others do not UseGoogle.com to look for resources for Webcam writing drivers for Linux and other non-Windows operating systems These pages will explain the data format of the camera Amost helpful resource is Sourceforge:

http://www.sorceforge.net/.

Google.com search phrase: +CCD

Super Circuits Web site.

General industrial electronics; wire and cable; video

cameras; test equipment Local store in Portland, Ore

Wm B Allen Supply Company, Inc 202887

Wm B Allen supplies 35,000 items from over 150

man-ufacturers For the robot builder, their electronics,

video, and tools sections will be of most interest The

company is primarily in the alarm, security, and

con-trolled access business.

con-x V Zoomkat: Web Based

http://www.geocities.com/zoomkat/

Web-based control of servos (via a Mini SSC II servo controller) Details and programming examples for using servo control with a Web cam.

See the description in Video for more information

about this section.

2820 San Tomas Expressway Santa Clara, CA 95051 USA

CCD and CMOS Imagers

When I started robotics, consumer video cameras used a high-voltage imaging tube

called a Vidicon to render a picture Vidicons tended to be large and required a age power supply The whole thing was heavy; with a lens, the typical video camera wasthe size of a lunchbox and weighed several pounds

high-volt-These days, cameras are the size of a cockroach—a regular-sized cockroach, not

those brutes you encounter in New York City!—and require only minimal voltage to run.The cameras are cheap, too You can buy a decent miniature black-and-white video

camera for under $50; color versions are more, but still reasonable These cameras,

which use only solid-state components, are intended for security applications The betterones operate under fairly low light conditions

Solid-state video cameras use two kinds of imaging electronics: CCD or CMOS CCD imagers (the CCD stands for “charged coupled device”) is generally considered to offer a sharper picture and offers better low-light sensitivity CMOS imagers cost less, but on the

whole, don’t deliver the sharpest pictures While there are some CMOS imagers intendedfor low-light operation, most are not as sensitive as their CCD brethren

 (408) 350-5100

 (877) 436-8366

 http://www.foveon.com/

Makers of high-resolution CCD color imagers Some

technical documents available on the Web site.

Single-chip CMOS black-and-white and color imagers—

”Single-Chip CMOS Image Sensors

(Camera-on-a-Chip).”

The company designs single-chip image sensors for

cap-turing and converting images for cameras Their

imagers are used in a number of products and designs,

including the CMUcam (see

http://www-2.cs.cmu.edu/~cmucam/).

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APIs See the description in Video for more information

about this section.

AVR + GameBoytmCamera = Fun 202277 http://pages.zoom.co.uk/andyc/camera.htm Detailed information, circuits, and sample program- ming (for the Atmel AVR microcontroller) for using the Gameboy camera for crude machine vision

Video Images: Analog or Digital

The vast majority of solid-state video cameras available today provide an analog output

signal (specifically, it is a composite signal that combines synchronization and

lumi-nance signals, and with a color system, chromilumi-nance signals as well) Depending on

where in the world you buy your camera, this signal is compatible with your TV and

VCR

For example, color cameras sold in the United States are compatible with the NTSC

color standard; black-and-white cameras, with the RS-170 standard Cameras for sale inmany parts of Europe follow the PAL standard Some cameras are selectable between

NTSC and PAL or are available in either version

For the most part, cameras with composite signal outputs are only modestly useful inrobotics The signal must be processed before the electronics (computer, microcon-

troller) on the robot can use it The processing might be in the form of a frame capture

card, or it might be some homemade sync separator and analog-to-digital comparator

circuit However, a minority of solid-state cameras provides a digital output—usually 8-bitparallel, but also USB serial A parallel digital camera can be directly connected to your

robot’s computer or controller; software running on the robot reads the video signal by

processing the digital data

Says the Web site, their mission is to “create a simple,

robust vision system suitable for real time robotics

applications The system aims to perform global low

level color vision at video rates without the use of

spe-cial purpose hardware.”

How to connect a Nintendo Gameboy camera (no

longer made, but still available from some quarters) to

a PC parallel port Then how to program the PC to

know how to read the data the camera is sending it.

Includes circuit diagrams, how-to, and program code.

Java Media Framework API 203001

http://java.sun.com/products/

java-media/jmf/index.html

Using Java for media and vision Says the Web site, “The

Java Media Framework API (JMF) enables audio, video

and other time-based media to be added to Java

appli-cations and applets This optional package, which can

capture, playback, stream and transcode multiple

media formats, extends the multimedia capabilities on

the J2SE platform, and gives multimedia developers a

powerful toolkit to develop scalable, cross-platform

technology.”

The JMF is capable of capturing, processing, and

dis-playing data from most any analog camera Can be used

with any computer that supports Java, including Linux

Newton Research Labs, Inc 203762

441 SW 41st St.

Renton, WA 98055 USA

video-programming & apis 669

QCUIAG (QuickCam and

Unconventional Imaging

http://www.astrabio.demon.co.uk/

Tips and techniques for using the QuickCam and other

CCD/CMOS cameras for astrophotography Many of

the same techniques can be used for robot vision.

QuickCam Third-Party

http://www.crynwr.com/qcpc/

Information about drivers for various computer

plat-forms, such as Linux, for the QuickCam brand of video

According to the Web site, “RobotVision2 (Rv2) is a

real-time image processing software, using Video for

Window (VFW) compatible camera, such as QuickCam,

as the image source Rv2 supports 1, 4, 8, 16, 24 and 32

bit-per-pixel, all uncompressed.”

http://www.WebRemote.co.uk/

The WebRemote Device Controller allows you to

con-trol devices across a Microsoft NetMeeting

connec-tion Using just the NetMeeting software, you can

con-trol a Web camera (connected to the appropriate

servo pan-tilt head, ofcourse) from anywhere in the

world Use it to command the video on your robot—

or even your entire robot—from a Web browser Free

download.

See the description in Video for more information

about this section.

1376 N.W 22 Ave.

Miami, FL 33125 USA

One Mill Line Rd

Bobcaygeon, Ontario K0M 1A0

 (404) 872-0722

 (404) 872-1038

 (800) 752-3571

 sales@polarisusa.com

 http://www.polarisusa.com/

Polaris supplies security cameras and wireless

transmit-ters for video.

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One Supercircuits Plaza Liberty Hill, TX 78642 USA

 (800) 335-9777

 http://www.supercircuits.com/

Super Circuits sells wired and wireless video cameras, miniature (including the size of a shirt button) cam- eras, and video transmitters and receivers Good stuff at reasonable prices.

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X10 Wireless Technology, Inc 203076

15200 52nd Ave South Seattle, WA 98188 USA

con-x V

video-transmitters 671

Micro-miniature video transmitter.

Photo Polaris Industries.

Transmitter (with integrated camera) and

receiver pair Photo Polaris Industries.

G Wheels and Casters

If it rolls, it’s in this section where you’ll find many

resources for wheels and casters (even tank-like treads)

suitable for mobile robotics Products include tubeless

wheels designed for wheelchairs, but infinitely usable in

robotics; omnidirectional wheels that rotate like a

nor-mal wheel but also allow perpendicular motion;

spheri-cal casters that don’t swivel; ball transfers that act as

uni-directional casters; and much more.

Several of the sources in this section manufacture

wheels and casters and do not sell them directly to the

public They can be purchased from distributors, as

indicated on the company Web site Other sources do

provide for direct purchase, usually through an online

Web store, but also through mail order.

SEE ALSO:

Materials: A number of general materials

sources also offer “materials handling” products,

which include wheels and casters

Power Transmission: Shafts, bearings, pulleys,

chains, and other components for driving wheels

Retail-Hardware & Home Improvement:

Source for low-cost wheels (e.g., replacement

lawn mower) and small casters

Retail-Surplus Mechanical: Common source

for new and used wheels and casters, usually at a

AIRTRAX manufactures and distributes the

DireXtional (omnidirectional) Wheel, intended for

heavy-duty materials handling, and wheelchair wheels.



800 N Clark St.

Albion, MI 49224 USA

wheel-x

American Caster & Material

2603 NE Industrial Dr North Kansas City, MO 64117 USA

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1 Noyes Ave.

East Providence, RI 02916 USA

Applied Industrial Technologies 203445

One Applied Plaza

Industrial bearings, linear slides, gears, pulleys,

pneumat-ics, hydraulpneumat-ics, and other mechanical things Also hosts

Maintenance America, online reseller ofindustrial tenance supplies and general industrial supplies (wheels, casters, fasteners, and more), tools, paints, and adhesives.

main- x

745 South St.

Chardon, OH 44024 USA

 (800) 544-8978

 http://casterconnection.com/

Casters and wheels When I last visited I didn’t stay long because of the irritating Web site design with all sorts of popup message boxes.

wheels & casters 673

Selecting the Right Caster

Robots with coaxial drives—two drive wheels on either

side—need something on the front and/or the back to

pre-vent them from tipping over A common approach is to use

casters If the robot’s drive wheels are mounted along the

center line of the robot, then two casters are used One is

placed toward the front of the robot, and the other toward

the back If the drive wheels are placed at one end of the

robot, then only one balancing caster need be used

For small roving robots, the caster is fairly small The

smallest commonly available caster has a wheel of about 1

5/8 inches; smaller models are available, but are not as

easy to find The 1 5/8-inch caster will work with robots that

have 2- to 3-inch-diameter drive wheels The larger the

drive wheel, the larger the caster (This doesn’t always hold true, depending on whetherthe motors and wheels are mounted on the top of the robot’s base, or below it When

mounted on top, there is less ground clearance, and the caster must be smaller.)

A problem with the very small casters is that, well, most aren’t made very well They

are designed for extremely light duty, so their ball bearing swivel mechanism is cheaplymade This can cause the swivel to bind up or stick when used with a light load, such asyour robot When selecting a caster, spin its swivel If it catches or binds up at all, selectanother model or brand (or another caster in case you simply got a bad one)

If your robot is small and light (under a few pounds), you should also avoid casters

where the swivel is stiff because of heavy grease Otherwise, the caster may not turn

readily under the light weight of the robot

Casters add balance to wheeled robots.

 Dan@cruelrobots.com

 http://www.cruelrobots.com/

Performance materials and products for combat robots Colson wheels (some are “combat ready” with heavy-duty hub already attached), axles, reducers, hubs, sprocket and chain, weapons, and casters.

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4560 Layhigh Rd.

Hamilton, OH 45013 USA

Manufacturer of materials-handling equipment and

parts Listed here mainly for their casters, wheels, and

 http://www.dbproducts.com/

Dave Brown makes a long list of items for radio-control

models Products are available in hobby stores or

online The lines ideally suited to robotics include:

• Adhesives/additives

• Carbon fiber building materials

• Covering materials

• Lite Flite wheels

The Lite Flite wheels are a common staple of robot

builders (I must be on my twentieth pair by now) The

wheels are light and fairly inexpensive, and they can be

attached to a variety of axles and motor shafts By

glu-ing a servo horn to the rim of the wheel, you can attach

it to a servo that has been modified for continuous

 (760) 758-5560

 info@douglaswheel.com

 http://www.douglaswheel.com/main.htm Douglas Wheel makes aluminum wheels for go-carts, scooters, dune buggies, golf cars, and other vehicles Cart wheels are available in 5-inch and 6-inch sizes You can see the full line of products in their printed cat- alog-I’ve tried to get one several times, but nothing has ever come You might have better luck.

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wheels & casters 675

Wheels, Tires, Hubs—Oh, My!

Rolling robots use wheels Or maybe they use tires (or

tyres, if you’re in the United Kingdom) Or maybe they use

hubs and tires Which one is right? They all are, and the

terms are often used interchangeably Yet it helps to define

exactly which is which, so here’s a short glossary on what

these terms should mean.

Wheels are made up of tires, mounted on hubs A tire is

rubber, plastic, metal, or some other material, and the hub

is the portion that attaches to the shaft of the axle or motor

(Similarly, the wheels on a car are made of the tire on the

outside, and the hub, or rim, on the inside.)

Some wheels for robots are molded into one piece

Others, such as the Dave Brown Lite-Flight wheels, are

composed of two separate pieces assembled at the plant The Lite-Flight wheels use aplastic hub that attaches to the motor shaft or axle, and onto the hub is mounted a foamtire

Some more terms:

• Load wheels are wheels with a metal or heavy-duty-plastic hub They are for heavy

loads

• Press-on tires are wheels without hubs; you press the tires (sometimes they’re just an

O-ring) onto hubs

Wheels are tires mounted on hubs.

Du-Bro Products, Inc 202134

P.O Box 815, 480 Bonner Rd.

Wauconda, IL 60084

USA

 http://www.dubro.com/rcproducts.html

Du-Bro is a leading manufacturer of hardware, wheels,

and accessories for radio-controlled models See listing

under Radio Control-Hardware.

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12691 Monarch St.

Garden Grove, CA 92841 USA

cast-x V

1350 N Acacia Dr #2 Gilbert, AZ 85233 USA

Model R/C tires, from Du-Bro.

Photo Du-Bro Products, Inc.

Edmond Wheelchair Repair

Wheelchair and scooter parts, including motors,

wheels, and batteries.

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Using Ball Transfers as Casters

Ball transfers are primarily designed to be used in materials

processing— conveyor chutes, and the like Ball transfers

are made of a single ball, either metal, plastic, or rubber,

held captive in a housing They function as an

omnidirec-tional caster for your robot

The size of the ball varies from about 11/16 to over 3

inches in diameter Look for ball casters at mechanical

sur-plus stores and also at industrial supply outlets, such as

Grainger, McMaster-Carr, Outwater Plastics, MSC Industrial

Direct, and others

Ball transfers can be used as omnidirectional casters.

 (203) 790-4100

 (203) 790-4445

 sales@ergotechinc.com

 http://www.ergotechinc.com/

Manufacturer of Roll-Flex multidirectional wheel Use

‘em for three-wheeled robots that can travel and turn in

any direction The Roll-Flex rollers are available as

sim-plex or dusim-plex (one or two sets of “tires”) in diameters

Suppliers of tubeless wheelchair tires Also sells casters,

batteries, and hub brakes for wheelchairs.

hand- x V

KC Marketing Group, Inc 202531 CasterSupply.com

10 Dubelbeiss Lane Rochester, NY 14622 USA



400 Heaton St.

Hamilton, OH 45011 USA

directional caster, heavy-duty omniwheel, and

Transwheels The Transwheels are notable: They are

lightweight plastic, available in 2- and 4-inch-diameter

models, can be used as omnidirectional wheels, and are

considerably less expensive compared to other

Kornylak Omniwheel Photo

Kornylak Corp.

Omniwheels Go Your Way

Imagine a wheel that spins like any other wheel, yet also

allows for sideways motion That’s an omnidirectional wheel,

multidirectional wheel, or omniwheel—an idea that goes

back to about 1910 The wheel is a series of small wheels or

rollers, mounted around the circumference of a larger main

wheel They’re popular in materials-handling applications;

the wheels are mounted in rows on top of tables or

convey-ors Boxes or other goods glide effortlessly along the wheels

and are allowed movement in any direction

For robotics, omniwheels have two principle applications:

• As drive wheels in three-wheeled robots An example robot that uses this design is thePalmPilot Robot Kit (PPRK), sold by Acroname and several others Rather than use twodrive wheels positioned opposite one another, the PPRK uses three wheels in a trian-gular configuration Only two motors propel the robot at a time, but the machine is able

to move in any direction by applying power to specific motors

• As free-wheeling casters, allowing for low-friction turning A problem with swivel ers is that the swivel may not spin freely in turns This causes the robot to lose accuratetracking and steering (if the robot is light enough, a caster that isn’t pointed in the rightdirection will cause the little critter to veer off to one side!)

cast-Omniwheels are available in sizes ranging from about 40mm (about 1.5 inch) to over150mm (about 6 inches) The wheel material is rubber or polyurethane Alas, omniwheelsare rather expensive, but for what they do, they do it well

Omniwheels can be used as casters or as drive wheels.

Photo Acroname, Inc.

Kornylak Transdisc Photo Kornylak Corp.

 (626) 448-6155

 linco@linco-inc.com

 http://www.linco-inc.com/

Casters Local retail stores in southern California.

4851 Shoreline Dr

P.O Box 118 Mound, MN 55364 USA

wheels & casters 679

Airless tire from NPC Photo National Power Chair

Nighthawk Manufacturing Inc 203775

2 51331 Rande Rd 224 Sherwood Park, Alberta T8C 1H3

 (630) 858-9161

 (630) 858-9103

 (none specified)

Makers of popular omnidirectional wheels, intended

for conveyor systems, but used a lot to make robots.

Reid is an all-purpose industrial supply resource See

listing under Power Transmission.

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4451 Caterpillar Rd.

Redding, CA 96003 USA

Here are some key sources for omniwheels, should you want to try some out:

Acroname Inc. (specialty retailer)

North American Roller Products (manufacturer of commonly used wheels)

(see listing in Wheels and Casters for address)

Phantasm (combat robot builder; makes custom omniwheels)

http://phantasm1.com/

Reid Tool Supply Co. (materials supply)

http://www.reidtool.com/

Superior Tire & Rubber

Manufacturer of industrial-size (forklifts and larger)

wheels, tires, and casters Here’s some of what they

offer:

• Polyurethane and rubber press-on tires

• Polyurethane and rubber load wheels

• Superior STR casters

• Custom-engineered tires

• Polyurethane and rubber track pads

• Custom molded elastomer products

• Cushomatic solid pneumatic replacement tires

10341-67th Ave SE Lake Lillian, MN 56253 USA

 (320) 382-6128

 http://www.tracksusa.com/

Tracks USA sells replacement snowmobile tracks Snowmobile tracks can be used with large outdoor robots and for combat robots Sells the popular Camoplast tracks.

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wheels & casters 681