Numbers and Units. Robot Line-Following. Nine-Volt Batteries. Clips and Test Leads. Power On! Solderless Prototyping. Solderless Breadboard Setup. Variable Resistors. Transistor Switches. DC Motors. Adding Gearhead Motors. Page 1 Navigate to page number of 2. About this book Introduction "I wrote this book because I love building robots. I want you to love building robots, too. It took me a while to learn about many of the tools and parts in amateur robotics.
Before the grand unveiling, take a careful look to see if anything is missing. Any empty spots? Maybe it needs a smiley face and googly eyes see Figure Stickers, paint, flags, and blinking lights are also attractive finishing touches. Be sure to name your robot something clever or thought provoking.
At the premiere ceremony, consider playing some music. Are celebratory beers in order? Mood lighting? Datasheets that describe a component in complete detail can be obtained instantly from the web sites of manufacturers and resellers. A quick search results in a plethora of robot-related material. Posted pictures and movies can be very informative and inspiring. Local robot clubs are even better resources.
For the social aspect, you get to meet new friends, both humans and robots. More importantly, informal discussions often provide insight or help with problem solving. Many clubs hold monthly or annual contests. If you have a competitive personality, these opportunities can be highly motivational. Although prize values are still relatively low, you might receive cool items you might not have purchased for yourself.
The physical locations of clubs can be found on the Web. Keyword searches work well. Most of the larger associations provide lists of links to other clubs. Involve your family in your hobby. Not only will they be more genuinely appreciative of your accomplishments, but their presence can also make the whole experience more deeply enjoyable.
When I went to my first robot contest in Illinois, I was struck by the family-friendly atmosphere. There were children of all ages, husbands and wives, grandfathers, grandmothers, and friends. Onward and Upward The next few chapters cover some important basics such as catalogs, safety, obtaining a multimeter, and numbering. The heart of this book is dedicated to each component, tool, and step of building a line-following robot. It begins with a description of line-following track requirements and an inspection of the completely assembled line-following robot.
Then, each chapter revolves around a piece or stage of designing and building the robot. You hold in your hand the complete blueprints and set of instructions to actually build the robot from scratch, without any prior knowledge of electronics, mechanics, or programming. By focusing on a single design, the book covers every related detail and subject in depth. There are a number of robot books that provide an enormous range of robot projects, but without the details necessary for a beginner to actually build any of them.
However, there are modularized circuits and milestones to provide you with accomplishments along the way. The final chapters include ideas and suggestions for where to proceed from here in the wonderful world of robotics.
If something is frustrating or difficult to make, or is otherwise turning out badly, then either you are using the wrong tool or you are using it incorrectly. In fact, some jobs are literally impossible without the right instrument. Using the correct tools in the correct manner makes almost any job fast and easy.
The same principle applies to parts. There are an infinite number of materials that you can employ to build a robot or provide a particular feature. Often, the greatest barrier is not knowing that a tool or part exists. Ordering Free Information A good place to start is to order some free catalogs.
Take a few minutes, now, to order complimentary printed catalogs see Figure from most of the retail companies listed in Table They also make for pleasant surprises when they arrive in the mailbox.
Table Micro electronics, surplus www. Jones electronics, surplus www. Most manufacturers themselves also have catalogs. Discovering Hidden Messages Besides their obvious content, catalogs also provide an unintentional education. Since every square inch of printed page costs money, the companies try to condense data as much as possible.
Considering Columns If you want to know the most significant differences in a family of parts, just check out the table columns the catalog companies publish to compare them. Hmm, if color, wavelength, dimensions, and brightness are all listed for LEDs, then those must be some of the most distinguishing characteristics between types of LEDs.
Counting Pages Another subtle message contained in a parts catalog is the number of pages devoted to a family of parts. If surface-mount capacitors take up a lot of space in a particular catalog, you can infer that enough people are buying enough of those parts to be worth listing them. The amount of space given to a variation of parts can also be noteworthy.
If there are twenty lines of text dedicated to one variation of a part, but only one line of text for another part, perhaps the one-line variation has an unnoticed limitation. On a sad note, if your favorite parts or packages seem to be receiving less and less coverage from subsequent catalogs, perhaps something is changing in the industry. It might be worth investigating whether that particular piece of technology is fading away. Comparing Prices The price list also tells a story.
The chips listed in Table all provide the identical logic function. So why the huge range in price? Why is it the most expensive? The lowest price on this list happens to be for a technology, 74HC00, that is very popular and has fully matured.
Of course, there are exceptions. With labor-intensive or rare-material parts, higher prices may be an indication of better quality parts rather than obsolescence or the latest technology.
In quantities of , many components are half the price of a single piece see Figure Consider informally organizing a group to buy a larger quantity of a particular item.
Not only will each individual lower the unit cost of their parts, but also the group splits the shipping costs. I try to support my local electronic, hardware, and hobby stores so that they will be there when I need them. There are some items, such tools and body materials, that are better to examine in person. However, for electronic parts, the costs are often exorbitant and the selection is limited in retail locations.
Most catalog companies offer better prices than retail stores because the stock is consolidated and is warehoused at a few low-rent locations. Online companies can further reduce costs over catalog companies by decreasing the size of printed catalogs or eliminating them altogether. Thus, even many catalog companies offer additional discounts for orders placed online.
Sharp drop in component price with quantity Watch out for minimum order amounts. Most online and catalog companies charge a handling fee below a certain total order size. Also, consider the cost of shipping. It tends to have a significant base price that grows relatively slowly with weight. In summary, by consolidating smaller orders into a single purchase and by buying in larger quantities, the per-unit price of components can be dramatically reduced.
Simply plan ahead or combine orders with friends or local club members. Retaining your health while doing so is a sign of greater intelligence. Robotics involves a number of potentially harmful or dangerous situations. This safety chapter is meant to introduce readers to a broad variety of concerns regarding the hobby.
However, many of the tools, chemicals, forces, and power associated with robotics can be dangerous. Minors should only attempt to build robots with the assistance of an adult. Following Instructions Always read and follow the instructions provided with equipment and materials. Remember, the information is coming from the experts. The rules are designed not only to keep everyone safe, but also to protect the equipment and to produce a high-quality product.
Keep manuals and safety sheets with their associated equipment. That way you know where to look if you lend the tool to someone or are having difficulty using it yourself.
As part of my research for this book, I reread some tool manuals and was delighted to learn some things I had either forgotten or missed on first reading. When in doubt, ask for help. Reading Chemical Labels The labels for chemicals are as important as the instructions for tools.
The MSDS lists all hazards and the appropriate preventions and solutions. These sheets are available from the manufacturer and often the distributor. The sheets are commonly posted on the Web. Donning Safety Glasses A single errant shard in an eye can eliminate your depth perception and half of your vision.
A chemical splash can impair or destroy both your eyes. Together with a sharp brain and steady fingers, your eyes are fundamental to building great robots.
Wear your safety glasses! See Figure Safety goggles protect your eyes There was a woman up the block from me who made a little extra money by sewing. One day, the needle from her sewing machine shattered during ordinary use, sending a piece of the needle into her eye. Freak accident? I always wear safety glasses whenever I work around machinery or chemicals.
I also wear safety glasses when snipping wires or cutting sheet metal. The lenses will become greasy, soiled, or scratched. Wearing Other Safety Clothes Wear appropriate gloves and long-sleeved clothing to protect yourself against irritation, minor scratching, chemical burns, or even poisoning.
I always wear long pants, long-sleeved shirts, chemicalresistant gloves see Figure , a dust mask, and safety glasses when working around chemicals. Resistant gloves protect your hands against chemicals Thick leather steel-tipped boots with puncture-resistant soles are appropriate when working with metals or large, heavy materials.
Try to use chemicals outside. If the room lacks windows, obtain proper ventilation equipment such as an exhaust fan. In cases of recurring or extreme exposure, consider using a respirator. Seemingly benign materials can irritate your nose, throat, and lungs when reduced to an airborne form. Wear a dust mask see Figure when sanding or drilling.
Even an inexpensive dust mask can help protect your nose, throat, and lungs Everyone knows that smoking is bad for you. But, sometimes people forget about the potential for smoking to act as an ignition source for flammable chemicals or fumes.
This is especially a danger in poorly ventilated rooms. Storing Properly Store chemicals and tools up high and lock them securely to keep them away from children.
Place chemicals and raw materials away from heat sources, such as soldering irons, heat guns, stoves, furnaces, and water heaters think of the pilot light. If you transfer chemicals to a different container, or simply expose something to a chemical during use, be sure to label the item properly, including all appropriate warnings.
Talking About Your Activities, Materials, and Tools Speak to your friends and family members about the items and chemicals you have. At the very least, wash your hands with soap and water. However, as environmental and material sciences progress, the negative characteristics of a particular matter is being given more significant consideration.
Many seemingly benign or marginally acceptable substances are now found to be too dangerous or polluting. Toxic elements are of serious concern. However, when disposed of properly, many can be recycled or chemically neutralized. Lead Lead is being banned from an increasing number of products including electronic components and assembly.
Airborne exposure to lead is the worst, followed by ingestion, with the least absorption through touch. High levels of lead can cause death in adults, but even moderate blood levels cause permanent loss of IQ in children.
Avoid purchasing products containing lead, including lead-acid or lead-gel batteries, even at surplus sales. It flows well. However, I made the switch to a tin-silver lead-free alternative see Figure With the correct temperature and practiced technique, lead-free solder works as well and even forms a stronger bond. Flux, the cleaning material within solder, is irritating and a potential carcinogen. Adequate ventilation and clean-up helps here. Mercury Old-fashioned mercury tilt switches are sure cool to look at see Figure However, mercury is a particularly toxic element.
Small amounts can poison you, as well as make their way into rivers and streams. Mercuric-oxide, silver-oxide, and even zinc-air batteries contain mercury. If you use a mercury switch in your robot and the switch shatters, spewing mercury all over your robot, how are you going to clean it up?
The robot is covered in toxin. Most types of consumer batteries are accepted at local hardware stores or Target or Wal-Mart for disposal and recycling at no charge. Seriously, a few minutes of your time here can make a significant impact on the environment. Nickel-metal hydride NiMH batteries are a superior replacement, in several ways. Take items containing cadmium to a local hazardous waste collection site for proper disposal.
Again, many local retail stores accept batteries for disposal at no charge. This initiative is also being adopted in various forms by states and countries throughout the world.
The purpose is to reduce the usage of certain harmful elements and compounds. Manufacturers that comply with the requirements can label their product RoHS.
This initiative is being adopted broadly across the electronics industry. The difference is usually that the newer part has either been certified or modified to be RoHS-compliant. Ironically, rather than leading to increased costs, RoHS parts are often slightly less expensive. In any case, RoHS is good for you because you get the same great functionality with less nastiness. Shocking Electricity is the lifeblood of a robot. Too much electricity or its passage through a vulnerable location can be harmful to the robot as well as the designer.
AC vs. However, those appliances were designed by people with more experience and education than the ordinary hobbyist has. As such, this book avoids projects related to AC. Instead, stick to low-voltage DC Direct Current applications.
In fact, all of my robots run from standard consumer batteries. Although a capacitor charged by a pair of 9-volt batteries can still wake you up, and obviously volt car batteries can kill under the wrong conditions, the overall risks are dramatically reduced in comparison to the household outlet.
Using Rechargeable Batteries and Professional Transformers Rechargeable batteries have become very practical in recent years, not only from an environmental standpoint, but also financially. Specially designed rechargeable lithium batteries and nickel-metal hydride NiMH batteries are readily available.
Tethers power lines or other cables tend to get tangled and confine the device to a clumsy, short range. If you need steady, long-term power, then purchase a voltage-adjustable DC power supply see Figure That way, even if the circuit breaker fails to trip, you can quickly cut power without having to touch the rampaging device. Unlike circuit breakers that detect too much total power, GFCI outlets disable power when not all of the electricity being sent out from the outlet is returning.
This is more likely in wet conditions, where the water provides an electrical path from the device to your body. Like circuit breakers, GFCI outlets can be lifesavers. Another place to consider a fuse or circuit breaker is on the robot itself. The portions of the circuit with regulated power go through a voltage regulator chip.
So, check their datasheets to make sure your regulator chips have built-in thermal and current overload mechanisms most do. For circuits on the robot that connect directly to the battery, such as the motors, use a fuse or circuit breaker to prevent damage or fire.
A few seconds after the fault is corrected, they cool down and automatically reconnect the power. A classic single-use fuse left versus PPTC self-resetting circuit protection devices right Saving the Ground Prong Never cut off the third prong from a power cord see Figure Grounded three-prong plug With the advent of the third prong, the metal case can safely dispose of the electricity back into the outlet instead of into the person touching the device.
A trip to the hospital is going to be a lot more expensive. Rooms with just a few two-prong outlets are becoming a thing of the past.
Disconnecting Power Always physically disconnect power from the robot's circuits before working on it. On larger robots, not only should the batteries be disconnected, but they also should be literally removed from the robot during maintenance.
This is safer for the builder and it prevents physical damage to power sources. Either way, use test probes to ensure no power remains. Large, charged capacitors are one of the reasons that television sets and computer power supplies can be so dangerous to service.
Never touch a live circuit with both hands—you want to avoid creating a path through your heart. You should also wear rubber-soled or other insulating-soled shoes. An electrical path from a hand through your chest and out a foot can be deadly.
Ground paths work because the electricity makes its way through the path of least resistance. One last point: human skin is much more conductive when wet. That includes rain or sweaty hands gross!
Sorry about your arm. Even if intended for good purposes, moderate-sized motors can produce significant force. Wonder why? Motors and power components tend to get hot during use. Think about the amount of electrical work being performed by each piece and the amount of current it is receiving.
Every electronic or mechanical part wastes a portion of the power it receives as heat. Additionally, bright lighting makes it easier to spot mistakes, especially in circuit boards. If the workpiece is easy to see, it reduces the likelihood of leaning way into the piece or squinting. Whenever possible, purchase fluorescent lights see Figure Not only are they energy efficient, but they run cooler.
Hmm, are those two factors related? A nice desk-mounted adjustable table lamp is a must. Desktop adjustable lamp with fluorescent bulb Staying Rested and Level-Headed Fatigue and frustration can cost you and your robot. Plan ahead to finish your robot well before a competition. Relax, take breaks, and enjoy your hobby. Multimeter features are broken into groups: must-have, nice-tohave, and optional.
The chapter concludes with an analysis of three multimeters. A multimeter is a required tool for robot building. You will need a multimeter to perform the experiments and build the projects in the chapters that follow.
See Figure for an example of a multimeter. What follows are brief descriptions of the features available on multimeters. Digital multimeter with test probes Digital Digital meters display measured values on an LCD liquid-crystal display similar to a calculator see Figure No guessing or interpretation is needed.
Analog meters have a needle that swings back and forth, with line markings underneath see Figure Every digital multimeter meets this requirement. A range of 0. Every basic multimeter meets this requirement. Needle display of an old-fashioned analog multimeter DC Current Measured in amps, DC current indicates how many electrons are speeding by per second. Resistance Measured in ohms, resistance indicates how much something opposes electricity going through it. Probes or Leads The meter should come with the cables see Figure needed to connect it to the parts to test.
Ironically, really expensive pieces of equipment, such as many oscilloscopes, require probes that are sold separately. Test probes or test leads Figure Many multimeters have this feature, but the range is usually less broad.
This is an important feature because it can help classify different diode types and test and identify transistors. It can even light up LEDs. Most multimeters have this feature.
Continuity Measured in ohms, continuity indicates whether an electrical connection exists between two points. Frequency Measured in hertz, frequency indicates how many times something is occurring per second. If the meter has a frequency function, get one that at least measures up to 45, Hz 45 kHz. Some multimeters have this feature, but the range is usually less broad. Meter displaying kHz frequency measurement Duty Cycle Measured in percentages, duty cycle indicates how often a measurement is high as opposed to how often a measurement is low.
This turns out to be an important measurement in robotics, as it is the key to PWM pulse-width modulation. Only some multimeters have this feature, which often appears in frequency mode. Autoranging automatically determines the range and subsequently bumps it up or down as necessary, which is nice. Autoranging can be annoying if the measurement is occurring on the border between two ranges, because the device will keep switching between the modes unless the multimeter also has some sort of range-hold button.
Only the mid-range and high-end multimeters have the autoranging feature, which you can easily identify by uncluttered dials see Figure Luckily for the battery, my meter has auto power off. The bipolar type of npn or pnp is usually determined by the user inserting the transistor into different socket holes see Figure See Chapter 16 for detailed steps on testing with a transistor socket or diode feature. Dual Display A dual display includes a small, second set of digits in a corner of the display so that other measurements or calculations can be displayed at the same time as the ongoing value.
This is almost a requirement for maximum, minimum, and the other calculated features, since the ongoing value is otherwise not displayed. Many meters have this feature. Maximum A maximum mode displays the maximum value measured. While the meter continuously measures, you can exercise the various parts of a circuit, pausing every so often to view the maximum value read by the meter.
Many multimeters have this feature. Transistor test socket Minimum A minimum mode displays the minimum value measured. See the Maximum feature, previously described. Stand Most meters have a foldout piece to prop the meter up at an angle on the desktop see Figure This makes it easy to read the display while working on the robot. Optional Features Here are some bonus features that are available on some multimeters, but not absolutely necessary to have: Inductance Measured in henries, inductance indicates the amount of opposition to changes in electrical flow.
Very few multimeters have this feature; otherwise, it would have made the nice-to-have list. This can be very useful for generating test logs. If available separately, consider purchasing the software at the same time as the multimeter, just in case the software becomes unavailable when that multimeter model is discontinued.
Only some multimeters have the data interface feature. This can be an extremely useful feature for examining the quality and grouping of data pulses and timing signals. Unfortunately, the resolution and maximum speed limit of multimeter-based scopes is rather limited at this time. A true, high-speed oscilloscope with a generous display is a different beast.
Few multimeters have a scope feature, and their price is greatly increased. Useful at night or in dimly lit areas.
Mainly higher-end or graphic-intensive units have backlighting. It can be useful for checking circuit timing or servo commands. Few multimeters have this feature. Temperature Measured in degrees Celsius or degrees Fahrenheit, a temperature mode indicates how hot or cold something is.
Sound Measured in decibels, a sound mode indicates how loud or quiet something is. It could be useful for motor, speaker, or microphone volume testing.
Count A counter measures the number of times something occurs, regardless of length of time. Instead, they average their readings over a short period of time and update the display only a couple of times per second analog-nostalgic supporters point to this weakness.
So, some digital multimeters supplement their display with a bar graph, which is a rapidly updating single-axis line see Figure Digital bar graph allows DMMs to approach responsiveness of analog meters Data Hold Data hold prevents the screen from changing from the currently displayed value.
Most meters continue to display the current measured value but place the held value somewhere else on the screen. Data Auto A data-auto mode periodically moves the measured value to the smaller portion of the dual display. Most multimeters have this logic mode feature. Meter transitioning through logic states Memory Similar to the memory feature available on most calculators, memory mode on a multimeter can store one or more measured values.
When only a single value is frozen and stored elsewhere on the display, this feature is simply another name for data hold. This shows the change in value, rather than the absolute value. Some multimeters have this feature. Offset An offset mode shows the difference between the value stored in memory and the current value being measured.
The meter is almost always operated with the boot installed, unless space is a serious issue. Rubber boot edge cover for meter If a rubber boot is available but not included with the meter, it might be best to purchase the boot at the same time as the meter. The boot may no longer be available when the meter is discontinued. Most multimeters have a boot available.
Because of the danger from the higher voltage and current capacity of household outlets, this book only involves DC.
Every basic multimeter has this feature. Many multimeters now have this feature. AC Current Measured in amperes, AC current indicates how many electrons are speeding back and forth per second. Obtaining Hook Probe Adaptors The standard test leads that come with most multimeters are appropriate for probing circuit boards and briefly touching wires or connectors. Hook adaptors see Figure and alligator clips are available that slide over each probe and clip to the circuit being tested, resulting in hands-free connections to jumper wires and IC pins.
The hook adaptor tends to be preferable for most low-voltage digital circuits. Hook adaptor for standard probe A pair of hooks can be more perilous in that the multimeter becomes physically attached to the circuit or test points. The hooks make it more difficult to suddenly withdraw the leads in the event of high voltage or other error.
On the other hand, a single hook connected to ground can actually be safer than no hooks at all. This allows the technician to hold only a single, hookless probe, making a pathway across the heart less inviting and allowing the technician to concentrate on a single point. Because hook probes are referred to extensively throughout this book, it would be helpful for you to purchase a pair see Table Instead, try to understand the specifications so that you can find an existing model that meets your needs.
See if you can guess the prices for them. It appears to have several siblings with slightly rearranged cases and model numbers. For example, with a reading of 1. All together, there are five ranges on the DC voltage section of the dial: 0. That means the meter is going to be able to measure current levels lower than 0.
When you switch the meter to measure high current, you need to move the positive red test probe to the high-current socket. Internally, the high-current socket connects to a fuse with a different rating. The disappointing aspect about this meter is that it can only measure up to mA in low-current mode. Somewhere up around mA would be preferable. Good minimum and maximum. It means you can turn the dial to the ohm setting for the best accuracy of measuring lowvalue resistors. It can test the gain of transistors.
But, you can determine that from just looking at the photograph. There is no capacitance mode on the dial and there is no button for a backlight. Yet, this is perfectly fine as a disposable meter or for students who plan to take only one electrical engineering course. Large display and units Easier to read, particularly if the meter is off to the side of your work area.
Nice touch. I strongly recommend that you obtain an autoranging meter. This is the very best reason to step-up from the low-end meter. The temperature range is wonderfully broad, as is true with almost all meters that support temperature measurement.
The manufacturer says the meter can measure up to 30 MHz, which is much higher than most meters. Auto power off This saves plenty of batteries. Continuity test Beeps when a connection is made. Rubber boot Helps protect against breakage if you drop it. The test probes are higher quality than most. The meter uses a pair of AAA batteries. This has an unfortunate consequence: those meters are unable to test blue and white LEDs in their diode test mode because over 3 V is required to do so.
It has all of the features of both of the previously described multimeters and some additional plusses. Higher-end digital multimeter 50 40, count display The display has five digits, which is quite a lot. The high number of digits in the display suggests this meter is capable of higher accuracy and precision than lower-end meters. DCV accuracy 0. However, since the tolerance of most robot circuits is fairly rough and wide, the increased accuracy is really only necessary for professional designers.
True RMS Accurately measures the voltage of alternating current even if the signal shape is a little odd. In that case, an oscilloscope would be better. I never use it.
Backlight It has a beautiful bluish-white backlight. Although I rarely use a meter in the dark, it is nice to know that this meter has that capability should I need it. I can set up the meter, power it off when I want to take a break, and then power it back on when I return without having to reselect the correct measurement mode. The other end of the USB cable connects optically to the meter—which means the information is transmitted with light rather than an electrical connection.
This avoids problems with the computer or household power contaminating the meter readings. The meter comes with the PC software, rather than being available separately for an additional cost. Intermediate Robot Building, Second Edition offers you the kind of real-world knowledge that only renowned author David Cook can offer. In this book, youll learn the value of a robot heartbeat and the purpose of the wavy lines in photocells. Youll find out what electronic part you should sand.
Youll discover how a well-placed switch can help a robot avoid obstacles better than a pair of feelers. And youll avoid mistakes that can cause a capacitor to explode. Want a robot that can explore rooms, follow lines, or battle opponents in mini-sumo? This book presents step-by-step instructions and circuit and part descriptions so that you can build the robot featured in the book or apply the modules to your own robot designs.
Finally, youll find the complete schematics for Roundabout, a room explorer that requires no programming and uses only off-the-shelf electronics. With Roundabout, youll use many of the same techniques used by professional robotics engineers, and youll experience many of the same challenges and joys they feel when a robot comes to life. What youll learn How to build a robot from scratch Digital electronics and moderate machining How to use and integrate modern modules useful to all robots: power supplies, motor couplers, motor drivers including H-bridges , opponent and obstacle detectors, and floor sensors.
How to embrace and extend the base robot design How to use Roundabout, which operates with off-the-shelf brains, so that no programming is required How the additions of a microcontroller, configuration switches, and even a music module all come together as a final two-tier automaton showing a versatile Robot who is seemingly the master of its domain. Who this book is forThis book is aimed at intermediate builders: adults, college students, and advanced high school students. It requires background experience in electronics, at least to the extent covered by Robot Building for Beginners.
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