I have started participating in the electrical team more often recently, but I feel like I don’t know enough. I have been told that I don’t need to know a lot but I still feel like there are other things to know. Is it really just matching colors and finding power requirements for devices, or is there other knowledge that I should know.
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Since we’re working with 12 volt batteries, at the most basic level it’s matching colors and making sure the wire used is big enough to carry the load.
There’s definitely more to it, but when you’re just starting out you can get through a lot by knowing:
1 the motors that drive the robot need to be at least 12 gauge.
2 don’t mix the black/red wire pairs with the green/yellow wire pairs.
If you want to learn more, many teams have published their instructions for new students, I like to recommend team 3847 Spectrum’s : here
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do you think it is smart to memorize a bunch of things like suggested wire size for batteries or other stuff like that? I feel overwhelmed when I see some teams’ electrical guides or feel like the info I’m getting isn’t enough.
There’s definitely more to it than just matching colors and checking power needs, but don’t worry—it’s all learnable and will make you much more confident in your subteam.
Crimping and making solid connections is key, since loose crimps can cause tons of issues. Search up videos on YouTube that show you how to crimp, and better yet, have your mentors take you through practicing how to crimp. Plus, organizing wires neatly and securely not only looks better but can make troubleshooting so much easier later. Labeling everything will also help you and your teammates navigate the system faster, especially during high-pressure situations.
Understanding power flow is another big one. The basics of how the battery, breakers, and components connect are helpful to know if you’re troubleshooting. Here’s a good resource from WPILib that has some pointers on power distribution specifically in FRC as well as a general overview on everything else (Introduction to FRC Robot Wiring — FIRST Robotics Competition documentation). And speaking of troubleshooting, learning to use a multimeter to check connections or track down shorts is also an awesome skill and it’ll make you everyone’s go-to for quick fixes.
Finally, don’t forget about safety. Electrical work has its hazards, so getting familiar with safe practices, like avoiding shorts and handling batteries properly, is huge.
Ask lots of questions and see if a mentor can walk you through these basics hands-on (this is probably my best advice as from my experience you can only really learn electrical by shadowing someone experienced and practicing it yourself). It’s a lot at first, but every little bit you pick up makes a difference!
Depending on your team standards, 95% of the time you’re going to use:
- 12AWG (awg stands for american wire gauge, smaller number=bigger wire) for motor wires
- 18 AWG for the CAN and signal wires, and
- 6 AWG for wires between the battery and the power distribution panel.
Some teams size up to larger wire to lessen the amount of power lost, but don’t worry about that now.
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Minimal knowledge must include the selection and placement of connectors (terminals).
Your team likely already has standard terminals for the different types of circuits (battery, motor power, CAN, sensor signals, sensor power).
Also, it’s critical that your team has a standard, consistent use of the receptacle-pin placement. It will quickly drive you crazy if some of your motors have receptacle (socket, female) connectors and some have pin (plug, male) connectors.
Without knowing your electrical team’s size or experience, here are some general notes to add to what is mentioned above.
- Use the right tools for the right job (i.e. don’t use random pliers to crimp or a pocket knife to strip wire).
- Tug test every crimp you do.
- Don’t work on the robot while it’s on (no mater what the seniors/mentors do).
- Minimize wire runs but don’t make the wires guitar string tight.
- Zip ties and electrical tape are good but use them strategically
- Wear gloves when working in the robot
ive never heard of an electrical team using gloves. could you explain more?
purely out of curiosity is there one for software? this is a great resource though
Honestly, my students have rarely listened my advise on that and have had their hands cut up by bolts and/or aluminum/plastic that hasn’t been filed enough when reaching under superstructure to adjust wiring.
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Smaller number => larger wire?? It was how many passes in manufacturing a wire needed to go through to get that small … more passes through the process makes a smaller wire.
It’s not just wire that conducts, any metal will. I asked students to remove the pigtail off an old battery. One had a wrench on positive, and one on negative. If the wrenches touched it’d short out the batttery (!) I had them STOP and explained, I hadn’t thought of that possibility.
First, congratulations on reaching out for basic knowledge. Please keep doing that. People who learn new things as frequently as they can are likely to become highly useful.
Lots of good advice in this thread. One thing not mentioned so far: Read The FRC Manual [RTFM™]. Seriously, the Manual has rules regarding electrical wiring that are worth the trouble to study and comprehend. There’s a good reason, grounded in fundamental principles, behind every rule.
Also, look for mentors who have electrical expertise. AV professionals, electricians, technicians, engineers, etc. Good spark-chasers are less numerous than good mechanics, but they are out there.
Finally, and this may be a couple of years away if you’re just starting on your FRC team, consider studying electrical engineering after high school. My personal favorite recommendation is the Georgia Institute of Technology School of Electrical and Computer Engineering. I picked up some good basic knowledge there a few decades ago, and I hear they are still providing it.
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Don’t memorize for the sake of memorizing. Memorize a fact IF it lets you do something more correctly or in less time than if you hadn’t memorized it.
If you have time, put it into understanding instead. Build a model of the universe in your brain. Use it to achieve what you want to.
- If you crimp a connector wrong, what do you expect to happen? Why do you expect that to happen? Why might it take a while to discover a bad crimp? What’s heinous about that?
- How do resistance and current manifest themselves on an FRC robot in a way that people can sense? In a way that can be seen on things that are usually hooked up/displaying? In a way that can be detected by tools, like a multimeter?
- If you hook up a motor controller backwards, what do you expect to happen? Why does that happen?
- What do brownouts look like from the stands? What do they look like from the Driver Station? What does seeing a brownout cause you to expect to find when you examine the robot?
- When you tie down the wires (especially signal wires) too tightly, what do you expect to happen? Why might this be a concern in the first place?
- Why do you need to access wires after running them the first time? Why is it beneficial to know what connects to what?
- When a connector is loose or comes undone, what are the symptoms and why? How does it vary with different devices or connection purposes? How do you attempt to catch this before it happens?
- What are the implications of cutting some of the strands (when trying to strip the wire)? What can it ultimately lead to? How many strands is too many to lose?
- If you hook up something contrary to how the game manual says, what will happen, and when?
- Why might someone refer to voltage drop as “sag”? In what context does that make sense?
- Why is the electrical portion of FRC so prescriptive compared to, say, mechanical design?
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I will second this advice. Find a previous year manual and read the electrical rules. Most of the basics such wire sizing etc. are in there. Learning how to do propper connector crimping ahead of the season is a good idea as well.
Some of the topics I certify my electrical subteam students on include:
- knowledge of proper wire gauges and colors
- understanding the difference between power and data connections, including twisted pairing for CAN and the power vs motor side of speed controllers
- Wire routing + relief around articulating mechanisms and techniques to avoid snagging
- Proper labeling for easy troubleshooting
- Connector crimping techniques
- proper and safe Soldering techniques
I think if you have all this down, you should be good to go!
Does anyone have any reccomendations for CAN wiring? I don’t quite understand it fully, so what resources would you recommend. I went to the FRC can basics, but I was more so thinking about what I should know for troubleshooting since our team comes across a ton of CAN issues, regardless of whether its electrical or programming.
one way to reduce these is by adding strain relief, which is just adding in a few inches on every wire, and ziptying wire about 3/4-1/2 in. away from the connectors. I’m pretty sure soldering is best, but if you want connectors, 2x2 lever nuts are good, so are molex SL connectors, and andersons.
But from a troubleshooting standpoint, the only troubleshooting I’ve had to do is a continuity test. Do this for both yellow and green by taking the wire from the rio and putting one end of a multimeter on it, and the wire from the PDH/PDP and place it to the other. Make sure you are measuring resistance, the omega symbol. If there is continuity, then there will be a value other than 0L, or it will beep. If there isn’t then it will be 0L.
This is exactly why in my teams training I’ve been trying to incorporate the WHY of why we do things a certain way. Yes we want the members to know how to build and wire and program a bot, but we want them to know the whys as well