Hardware
Hardware – one of three parts for creating your ultimate robot! Check out these tips below to find simple, easy solutions to the most common problems as well as information to help your team maximize its robot design potential.
Quick Links:
Virtual Design
Design Strategy
Machining
Hardware Suppliers
Virtual Design
Using virtual design programs (such as, AutoCAD Inventor or Solidworks) can often be the best help for new teams. It allows the team to look and see design challenges before they actually build their robot parts. It can also make a more cohesive design and ensures that all parts will fit together properly.
However, knowing how to use these programs can often involve a steep learning curve. So is it worth it? And what is the best way to tackle that learning curve?
There are many different design or Computer Aided Design (CAD) programs available. Two popular programs amongst FRC teams are AutoCAD Inventor and SolidWorks, which both can be obtain for free through FIRST. Overall, CAD is just CAD, so use the pros and cons below to choose a program and stick with that program – in the end, experience with the program will make the difference.
If you have access to a CNC machine, make sure you use the correct program in order to interface with the machine properly.
SolidWorks
Pros:
- Used frequently in the design industry and college education systems. This means that the skills that you learn by using SolidWorks for FIRST will likely be beneficial in your future studies in technology.
- Quick to model parts. SolidWorks uses a simple drag and measurement system that is easy to learn.
- Very customizable user interface. Solidworks allows you to select the buttons and options you want on your control panel. As you get more experienced, you can customize this panel to work better for you personally.
- Constraining assemblies easier to accomplish. The “mate” tool in SolidWorks allows you to click on two different parts and select a constraint from a dropdown box. SolidWorks also automatically moves the part after you select the constraint, letting you see the effect before confirming the contraint.
- Good product documentation and tutorials. SolidWorks makes sure that the official tutorials cover as much of the product’s capabilities as possible. This documentation allows you to search for certain issues or capabilities and instantly get a good explanation.
- Large CAD library database available on the internet (e.g., 3D Content Central). This database allows you to download already-modeled parts to put into your CAD design, saving you valuable time and often giving you even-higher quality parts.
- Easy to use analysis tools (e.g., SolidWorks Simulation and Motion). SolidWorks has analysis tools built right into the system, which makes it easy to switch back and forth between drawing and testing.
- Good base of tutorials on YouTube. If you are looking for a tutorial of a specific feature of SolidWorks, the odds are that YouTube has the explanation.
Cons:
- Not very simple to animate the design. In order to make your design manipulatable and to test any real-world constrains, it takes another portion of the software (along with more knowledge/training) to make it possible.
- Lack of backward compatibility. Once a file is saved in a newer version of SolidWorks, you can’t open that file in an older version of the program.
Click here to order free SolidWorks CDs for your team. Fill out all of the information for your FRC team and SolidWorks will automatically send you copies of the SolidWorks Student Edition CD for free. These CDs should be in the Kit of Parts you receive from FIRST on Kickoff Day.
Your CDs also include a fantastic database of tutorials. But to start getting familiar with the program before your CD arrives, click here to go to the official Solid Works site. If you want more tutorials specifically about robots, click here.
Autodesk Inventor
Pros:
- More tuned for consumer systems. The program runs faster than SolidWorks on personal computers.
- Used frequently in college classrooms. This means that by learning Autodesk Inventor skills in FIRST, they can be applied at a higher level of education.
Cons:
- Big assemblies can be tricky. Error messages and bugs are harder to fix in Inventor than in SolidWorks.
- Not as applicable to industrial applications. Autodesk Inventor is not as commonly used in the industry.
Click here to download the free Student Edition of Autodesk Inventor program for your team. You also get this in the Kit of Parts you receive from FIRST on Kickoff Day. While you wait for your download or CD, go here to learn about the basics of Autodesk Inventor via their online tutorial videos.
Still have questions about CAD, SolidWorks, or Autodesk Inventor that we didn’t explain here? Ask us!
Design Strategy
How should you go about designing your robot? Should you have a different plan of attack as a rookie team than the other more experienced teams?
Tips:
- K.I.S.S. This mantra – Keep It Simple Stupid – goes for the majority of the teams, not just rookies. A simple design has less places to fail and means that more resources and energy can go to designing the fewer parts with higher quality. In addition, remember that it will be more fun to have a simple, working robot, than a complex, not-working or consistently breaking down robot at competition.
- Have a brainstorming agenda. Write up a general schedule for your team so that you spend an adequate amount of time brainstorming and designing, but not so much that you don’t have adequate time to actually build and test the parts. Search online – many teams open source their schedules for the year.
- Over-estimate the amount of time everything will take. This way you’ll plan for things taking you longer because of the rookie disadvantage (learning curve). Estimate at least double the time you’d expect for each activity and then budget time for an extra 2 to 3 major issues.
- Don’t forget about your programmers. They need the necessary time with the robot for testing and debugging.
- Ideally, rookie teams should strive to have a driving robot (just the chassis) within two weeks. Stick to the kit frame, and try to follow the FIRST instructions as closely as possible. The hardest part of creating the basic chassis tends to be electronics. Try and get a veteran team to guide you on putting a full system together.
- Know the parts that come in the kit. Use the Kit of Parts to your advantage, especially if you have a limited budget. Go to last year’s Kit of Parts website and scan through the list, looking up any parts that are unfamiliar to you so that you are best prepared for the Build Season!
- Look at previous year’s successful designs. Often, you can see similarities between the different challenges, which means that you can draw ideas from the similarities in designs. During the season, this means finding the past game most like the current one, and finding what was effective then.
- Look for standard FIRST design ideas. Research past robots to see the major types of mechanisms (rotary arm, forklift, etc.) used in FIRST and finding examples of effective designs that fit within your fabrication capabilities. Using the drive train as an example, it’s a matter of learning what the possibilities are: 4-wheel skid, 6-wheel skid, mechanum, and the exotics.
- Kitbot on steriods. Click here to watch a video about how to correctly design and assembly a chassis base using the parts you get in your kit. (Credit to FIRST Team #1114)
Still have questions about design strategy that we didn’t explain here? Ask us!
Machining
Tips for success, even without all the tools.
Often, rookie teams don’t have the benefit of having a shop space or industrial tools. If this is the case for you, don’t despair because there are plenty of options for your team.
- Raid the workbenches. Many of your team’s families may have perfectly usable tools lying around in the garage or basement room. Ask your team to gather as many tools as possible to make up your team’s “machine shop”.
- Buy a few, high quality tools. Invest in tools that will last the torture of Build Season and will be able to make all of the parts on your robot.
- Buy two of the high-need tools. These are the tools that will always be in demand while creating your robot, and most commonly are: drills, wrench sets, Allen key sets (in both the standard and metric sizes), and tiny screw drivers.
- Invest in prototyping materials. Prototyping can be done using wood, duct tape, cardboard, and even scrap metal – you can even ask your local scrap company for donations. These materials will allow you to quickly test any design ideas you have without needing to CAD or build official parts.
- Send out parts. Many teams without access to machine shops choose to CAD their parts and send them to outside companies to be machined professionally. However, this option is often expensive and requires extremely detailed CAD drawings.
Train Your Team: Machining
- Machining Websites. This website thoroughly explains not only safety for each of the tools, but how each of the tools should be used and how they work. This is a good option as preparation for training your team on the actual equipment.
- Training exercises. Have your team try out all of the equipment prior to the Build Season. For FIRST Team #3504, we have each group of students (about 3 to 4 students per group) build a project using the lathe, drill press, mill, horizontal band saw, vertical band saw, sanding belt, and various common hand tools. This gives every student on our team experience and confidence with the machines prior to the Build Season frenzy.
- Mentors. Make sure a mentor is always in the room when students are using the machinery. This will make the student more comfortable. They can ask the mentor for help if they are unsure of how to do something and it will also ensure that the students of the team are correctly and safely using the machinery as they make their parts.
- Comfortable with the machinery. This is the most important step towards (a) getting useful parts out of the machining process and (b) making your team as safe as possible. The more comfortable the students are with the machines, the less likely they will be to make a mistake. Doing exercises like the above helps the students achieve this level of comfort when working with heavy machinery.
- On the other hand, beware of becoming over-confident with the machines. Short cuts can result in mistakes, which can cause schedule delays or, worse yet, injuries.
Safety
- Safety Glasses. Always wear safety glasses in your working areas, no matter if the robot is on or if the students are machining items. Every student should have safety glasses on while at robotics. Make it part of the culture.
- Gloves – Yes or No? It is actually appropriate at times to work without gloves for safety reasons. When working with rotating machinery (mill, lathe, belt sander), it is often a good idea NOT to wear gloves, as they might catch in the spinning parts of the machine. Other times, like when students are working with hot or sharp objects, gloves should be worn.
- Shoes. Make sure that every team member has closed-toed shoes on around the robot or in the machine shop. You should also check the soles of your shoes at the end of the day to ensure that you are not taking any metal shavings home with you.
- Appropriate clothing and accessories. No dangling earrings, scarves, or other loose clothing that might get caught in the robot or the machines.
- Hair. Have hair ties available and ensure they are used as the length of hair dictates. Getting hair caught in machines or the robot can be extremely dangerous – even fatal.
- Hearing protection. Have ear plugs available for all of the team members, especially in the machine shop. Some of the machines/tools can be loud while cutting certain metals, so be prepared.
- Batteries. Make sure you use electrical tape, heat shrink, or other appropriate material to cover where the big wires connect to the actual battery. This is required at competitions and just good practice overall.
- Fire. Have multiple fire extinguishers in prominent places in your work space. Teach your team how to use them.
- First-Aid Kit. Keep a substantial first-aid kit on hand. Nobody wants injuries to occur, but you should be prepared if they do.
Still have questions about machining, training, or safety that we didn’t explain here? Ask us!
Hardware Suppliers
Common suppliers of FIRST parts:
- McMaster – This has as a wide variety of stuff. Good website. Expensive. Extremely fast shipping.
- Online Metals – Much cheaper than McMaster for most Al or Steel stock. Also has other metals and plastic.
- Bolt Depot – Good source of hardware (bolts, washers, nuts, etc.)
- SDP/SI – Large selection of gears and sprockets. Also a good source for shaft, shaft couplers, and a few other things.
- Harbor Freight – Cheap tools. Very cheap shipping. Most tools are lower quality, but perfectly usable.
- Grainger Industrial Supply – More mechanical parts.
- Digi-Key – Prime source of electronics components. Massive selection of IC’s.
- Newark/element14 – Electronics materials.
- Mouser Electronics – Electronics materials.
- Pneuaire – Lightweight air tanks for pneumatics systems.
- Andy Mark – FIRST-specific products, especially gearboxes and wheels.
- Banebots – Light-weight, Low-load gearboxes. Some with high gear ratios.
- 80/20 Inc – modular structural extrusion, connectors, and related hardware.
- Skyway – wheels.
- IFI Robotics – Victors, wheels, modular structure, and a few other things.
- Colson Caster – wheels, massive selection.
- Fastenal – 30% off fasteners (i.e. bolts, nuts, screws) and 15% off of general product for FIRST teams. Offer good through March 15, 2012.
Make sure your team utilizes FIRST Choice – AndyMark and FIRST have partnered to help FIRST teams get quality parts to build their robot. FIRST Teams start out with a number of “FIRST Choice” points that they can use to buy products through the AndyMark website. Find out more about this discount by reading FIRST’s explanation.
Still have questions about the hardware deals that we didn’t explain here? Want to add a site that we missed? Message us!
Software
Programming – part two of three to your ultimate robot. Read the tips and advice below to get off to a great start!
Quick Links:
Overall Process
Labview
C++
Java
Overall Tips for Any Language
It can be difficult at times to organize your programming process, especially if you have multiple programmers writing code at one time. How do you best organize your programmers? How should you organize your code? Where should you start?
Pseudo code. Before you even touch your computer, make a plan on paper of what you want to do. This goes for any programming language. This can start out as simple as listing the things you want the robot to execute. (example: “Move when the joystick moves”) Then you can get more detailed and start to list the steps it must do to complete this certain task. (1. Read value off joystick. 2. scale value. 3. send to motor). Continue to add detail before actually coding your program. (value = joystick -> get y axis; scaledValue = value times 12; etc.)
There is a proper way to pseudo code, and you can learn it if you want, but the more important part is just walking through what you want to happen and how you can get this to happen. After you know what you want to do, you just have syntax to worry about.
Keep your code organized. Get rid of old parts you don’t need and format your code so its easy to read (Netbeans has a feature where you can highlight your code, right click, and format it properly). When you start getting crazy with nested loops, having the code indent helps keep your code straight. Don’t be afraid to put in a return every once in a while. Walls of code can be off-setting and pressing enter an extra time after a section of code can make your code easier on the eyes and brain.
Come up with coding standards specific to your team. This means that all of your team’s coders follow a set of rules so that all of the code is consistent. For example, something like “every if statement must have a corresponding else statement”, “all statements must be commented”, or “variables must have meaningful names”. This will especially help you when your team has multiple programmers, making the code easy to understand and quicker to debug for people who may not have originally written it.
Repository. Your team should create a place to store your code, such as a central server that tracks different code revisions and histories. Some repositories have features that do ‘conflict resolution’ when multiple versions of the same file are checked in. They also serve as a place to keep code in case something happens to your local computer. There are free online ‘subversion repositories’ available, but rookie teams may even want to use google docs as an initial step.
For subversion, you can set up a free site on Unfuddle (which can be used for svn or git). Subversion is built into netbeans (meaning you can check things in and out through netbeans). However, if you want to check things in and out of the repository through Windows Explorer, you can download Tortoise SVN. Tortoise SVN is just a client, where the Unfuddle site would be the server where your files are actually stored. If you’re unfamiliar with subversion – go here.
Anyone can setup an svn, git, or cvs repository by installing a free server of that type on a computer that would act as your dedicated server. Then you can download corresponding client versions to add files to the repository on that server, or update them, or check them out. Then your repository would just be the address of that computer, assuming it’s networked.
Debugging. Always do basic debugging before you start messing with your code, especially when its the first time you run it. Making sure that everything is turned on and plugged in will fix a lot of problems. If your code is giving a really weird error, try restarting everything. This will fix a lot of problems, too. Also, if your having trouble downloading code, make sure you have the right IP address and that your Ethernet cable is plugged in to your cRIO correctly.
LabVIEW
Benefits:
- Graphical programming. LabVIEW allows better visualization of how the program is structured and how data moves through the program.
- Easier to learn. Experience shows that LabVIEW is easier to learn for those with no prior programming experience. If some of your team members have experience in either of the other languages, however, you may be ahead to use those.
- Implicit parallelism. Parts of the code that are not interdependent are run in parallel without any extra code or directives from the programmer.
- Extensive visual libraries. Existing libraries for image and signal processing and control systems are applications that LabVIEW was originally created for, so support for them is very good.
- Example autonomous code. For the last couple of years, FIRST has supplied example code for that year’s autonomous mode.
- Graphical, built-in debugging. Turn on debugging mode with the click of a button (no need to recompile and/or redeploy or run separate tools) which graphically shows how data is flowing through the program in real time. Probes display the values in the program.
- VCS Software. LabVIEW can be configured to work with certain VCS software, and offers a tool called LVMerge which can be used with some VCS software to merge LabVIEW files at the sub-file level.
Cons:
- Harder to find mentors. Laview is not as commonly used as C++ or Java, so mentors may have to learn the language as well.
- Skills are not transferable. The number of jobs available for LabVIEW programmers are much less that those for C++ or Java programmers, for those looking to directly bring skills learned in FRC into the workforce.
- Program code is not textual. LabVIEW needs to be installed to be able to edit a program. Also, version control utilities can only work on a while-file level, while text-based languages can be merged line by line.
- Program ordering is not implicitly deterministic. Implicit parallelism can also lead to some unanticipated behavior, but language features exist to establish sequential relationships.
The best set of online FIRST tutorials for LabVIEW are here. Watch these videos to learn more about FIRST-specific LabVIEW programming.
Also, view this PDF Document made by National Instruments (the company that makes LabVIEW and the cRIO) on FIRST-specific coding using the LabVIEW programming language.
Questions about LabVIEW? Ask us here.
C++
Benefits:
- Slightly faster than Java. The loop time for C++ programming is slightly higher than for Java, which, if used right, means the robots will have a slight advantage over robots programmed in Java.
- Real world applications. C++ is used in the programming work force for things like applications (such as Microsoft Windows) and video games, just to name a few. This means that programmers that learn C++ will be able to use C++ in their future education and career.
- WPI Library. WPI has created an immense FIRST library for C++, which means that many of the functions that rookie teams will use are easy to call and use in their code.
Cons:
- Harder to learn. C++ has a steep learning curve and can often take even experienced programmers time to get used to.
- C++ is operating system dependent. If you want to use C++ on different operating systems (like Mac and Windows), you’ll need to recompile your program for each platform you want to use before running it.
Watch this tutorial above made by FIRST Team #1503 on the basics of C++. To learn more in depth about C++ syntax and programming, click here to download a document also made by FIRST Team #1503.
Questions about C++? Ask us here.
Java
Benefits:
- Easier to learn. The time in which it takes to learn Java is considerably less than C++ programming. The learning curve is less steep when familiarizing yourself with the syntax.
- Often taught at schools. Most AP Computer Science courses and other programming courses taught at high schools are taught in Java, which means that students on a team can have supplementary education in the language that mentors do not have to teach.
- Useful for real-world programming situations. Java is used constantly in the programming work world, especially to code apps and other computer-based programs. This means that programmers that use Java will be learning a language that can prove useful to them later in their educations or careers.
- Very versatile. The WPI FIRST-specific Java library is immense and constantly growing. This means that not only are there pre-made functions that you can use for your code, but you can also make your own using similar techniques that were used for the WPI library. This means that Java is both simple while allowing complexity, if you choose.
- Easy to switch languages later. Java is very practical for students to learn in terms of it being similar to the languages that are used in real-world applications.
- Automatic Garbage. Java relieves programmers from having to deal with explicitly managing the memory in the code.
- Java runs independent of the operating system. This means that Java can run on multiple platforms (Mac, Windows, Linux, etc.). In other words, Java is cross-platform.
Cons:
- Slightly slower than C++.
- Less memory efficient than C++. Java does not allow programmers the flexibility to control their own “garbage”, which means that Java generally uses more memory that C++.
Read this tutorial below made by FIRST Team #3504 on the basics of Java. This is part of a three part series – click on the links for Part 2: Programming Your First FIRST Robot and Part 3: Syntax of Programming.
Also, this document explains how to introduce conceptual Java programming to people who have never seen programming before. This is an excellent exercise for teams to do for any language before the Build Season starts.
Getting started with FIRST Java. Use this website to become comfortable to FIRST Java, reading WPI’s descriptions of how to use this particular language successfully in FIRST.
Questions about Java? Ask us here.
Electronics
Electronics — part three of three to your ultimate robot. Read the tips and advice below to get off to a great start!
Quick Links:
Basic FRC Electronics
Sensors
Common Electronics Issues
Basic FRC Electronics
Electronics are a vital portion of the robot. Without electronics, the robot could not run. Learn about a few of the most important aspects of FIRST electronics below. Hover over any italicized word to see the definition!
Compact RIO. The most important part of electronics is the compact RIO, or cRIO for short. This on-board computer is like the human brain. It is responsible for comprehending code and sending it throughout the robot.
Battery. Coming in at second most important, this may seem very simple, but without the battery, the robot wouldn’t move at all.
Power Distribution Board. The third most important part of the robot is the power distribution board, or PD board for short. This is much like the heart of the robot.
Linking It All Together:
The battery is connected to the PD board, and the PD board distributes the correct amount of power to each part of the robot that is connected to the PD board.
To avoid over-powering certain parts of the robot, 20, 30, and 40 amp circuit breakers are easily attached and removed to accommodate changing wiring. The circuit breakers will cut the power to that particular portion of the robot in case it begins to be over-powered.
The main circuit breaker is 120 amps and is basically the on/off switch of the robot. It makes a huge circuit between the battery and the PD board, and it is the emergency stop on the robot.
The PD board connects to the motors, which turn a built-in shaft that typically turns gears inside a gear box. The gear boxes are mainly mechanical, but can be geared for speed or torque.
Speed controllers control the motors. Team typically use either jaguars or victors. The speed controllers take a given speed input and make the motors run at that speed.
Encoders are sensors that detect exactly what speed the motor is turning, which can be helpful for correcting the motion of the robot.
Servos are like motors, except they only turn 180 degrees and can hold specific positions. They are also much weaker than motors and cannot support much weight.
Spike relays are like speed controllers for pneumatics. For pneumatics information visit this website, created by FIRST Team #358.
Helpful Electronics Resources:
To go into more detail about the FIRST electronics setup, read through the powerpoint below.
- www.ifirobotics.com – This website has user guides for RC, OI, Victor, and Spike, as well as default code for those items.
- www.kevin.org/frc – This website holds code libraries for using encoders, gyros and the EEPROM.
- www.usfirst.org – Visit the official US FIRST website to find power distribution diagrams and the electronics & wiring rules.
- www.microchip.com – This website hosts the advanced PIC 18F8722 datasheet.
- www.chiefdelphi.com – This website is the main web forum for general discussion of FIRST robotics. It contains many electrical & programming-related whitepapers and a good place to go for help if you get stuck. You can ask questions to get helpful and quick responses from other FIRST teams.
- For additional electronics information visit – http://team358.org/files/electrical/
- For specifics on each indiviual part of electronics visit – http://patfairbank.com/static/electronics_controls.pdf
Still have questions about the FIRST electronics board? Ask here!
Sensors
Sensors can often make the difference between a good robot and a great robot on the field, especially in autonomous period. Sensors allow you to correct for any changes in environment when playing the challenge, and can make driving the robot easier for the drive team.
There is a plethora of sensors available to FIRST Robotics Competition teams, but not all are equal. View the presentation below, created by FIRST Team #1708, that outlines the different types of sensors and how they are used in the FIRST Robotics Competition.
Still have questions about sensors? Ask here!
Common Electronics Issues
Without electronics, your robot wouldn’t move at all. Without sensors, your robot couldn’t “see” the environment around it or itself. Because electronics are so vital, it is important that you know and understand what problems could occur and how to solve them. Below, you’ll find simple solutions to common FIRST electronics problem – if you have one that isn’t answered here, post it on Chief Delphi and you’ll likely get a response within minutes.
Problem: A connection seems to be faulty, but I can’t figure out where it is!
Solution: Using a multi-meter or something similar, check both sides of every connection. If you are using the right setting, (the current setting), then you will hear a beep or be notified by some other means from the multi-meter that there is a connection. Once you find a connection that doesn’t seem to be good, replace the wire with a properly connected one, but continue to check the wires in case there were multiple faulty wires.
Problem: I’m not sure whether I should crimp or solder.
Solution: Either method works fine, but there are pros and cons for each one. Soldering is more reliable, but requires some sort of covering (i.e Shrink Wrap Tubing). Crimping is quick and much faster, but it can take 5 crimps before you get one that is properly connected. Always test your connections no matter what before attaching it to the robot.
Problem: I need to drill onto the electronics board.
Solution: You can drill on a electronics board normally, but make sure you cover all open ports. You may want to remove any remnants of the drilling by using a spray canister of compressed air. Make sure to spray remnant away from the electronics. Do not blow on remnants because blowing onto the debris can cause them to fall back onto the board. A thin direct spray from computer cleaner does not blow the shards everywhere.
Problem: There is a current running through the frame of the robot.
Solution: Turn the robot off immediately and figure out where a wire is touching the frame. This is a serious thing and it should be dealt with immediately. Make sure this doesn’t happen by covering all lose wire ends with electrical tape or heat shrink. Don’t have any electronics mounted directly onto the frame. Instead affix them to a board such as Plexiglas or wood that is then mounted on the frame.
TIPS:
- Make paper cutouts of each part and your mounting board. Layout the paper copies so you know exactly what setup works for you.
- Measure twice, cut once! Make your job easier by doing it correctly the first time.
- Check each connection (either crimp or solder) by tugging on both sides of the wire before you attach it to the robot.
- Check the FRC manual often to make sure that you are in compliance with the competition standards.
