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.
