Hello FRC community,
I am a first year mentor for a rookie team. Many of the students on my team are very novice as far as experience. What are some good ways to keep the kids from starting fires, blowing things up, and damaging electronic hardware. I really want to keep the kids within budget and out of the hospital while creating good practices for the students.
Thanks all!!!
Obviously you don’t want to burn your shop down or cause any injuries, but mistakes aren’t all bad - students learn from them. A large chunk of what I’ve learned from FRC has come from doing something wrong the first time. Messing up is what makes us all human.
Training packages for safety and involve them in detailed budget, do they understand the impact of smoking some components. They seem to appreciate it more when they know the $ impact.
FIRST publishes a safety manual which covers a good deal of possible safety concerns that come up during build, such as battery leaks. You and your students may want to review it.
Hide the batteries until all of the wiring is checked (not kidding). Motor controllers in particular don’t like reversed polarity or power applied to the motor side of the controller. I don’t know how the roboRIO responds to reversed polarity but it could be an expensive lesson. Follow the wiring diagrams in the manual and you can’t be too far off.
Students should be instructed in the proper use of any shop tools before they can use them.
Electronics:
red to red, black to black, and make sure power input goes to the input side of motor controllers, not the output side
Training and supervision are key, especially with more advanced tools. You don’t have to spend a lot of money to stay safe but you DO have to spend a lot of time.
Teach your students to be aware of their work space and their tools by keeping it clean and organized. And most importantly when you see unsafe behavior use it as a teaching moment. Don’t just correct the student engaging in the unsafe behavior - share the lesson with everyone.
Safety training.
All of the things you mentioned can be avoided by training in good safety practices and healthy respect for the equipment, as well as a little knowledge.
You might even go through a training exercise with your students and get them to come up with all the rules, with your guidance of course.
For example, you mentioned damaging electronic hardware. What are all the ways you could damage a piece of hardware?
Brainstorm a list.
So how might you prevent each of those things from happening?
Physically dropping it - we will be very respectful and careful when we transport electronics. We won’t run or goof around. We’ll put it on a workbench well away from the edges and be aware of clutter or cables that could knock it down.
Wrong power supply voltage or polarity - we will check and double check the specs of the hardware before we plug it in. We will follow circuit diagrams exactly as written. We will check and double check the power supply connections before we turn anything on. We will measure the voltage and polarity of the supply with a meter if we aren’t sure. We will keep the power supply OFF until we are sure all the connections are made correctly.
You don’t need students to be so afraid that they have to check in with you before making any moves - but you do want them to learn to think things through before they do anything “risky”.
You could even create little checklists to attach to key pieces of equipment. For example for a power tool:
It would be a good idea to get some other mentors who know how to use the tools you have in a safe way to help teach and monitor the team members. They can be parents who have done some work on their car or on their house. They don’t need to know anything about robots.
Don’t let them touch the robot…
But that’s not much fun or terribly educational. Have them work under supervision, let them make mistakes that aren’t too costly (hospital/frying RoboRio etc) and stop them and explain what was about to happen to them. Honestly, mistakes are part of learning. If your students understand the costs of things and value the opportunity then you should be fine.
Plan things out, work through it systematically, and check everything.
Again.
Our first power on (after everything has been checked. again.) usually has all breakers removed, then one added at a time so we can check through each circuit individually. It’s not as much fun as turning it on and seeing everything light up, but it let’s us ensure each item is working before we move on. This saves time when we try run it later.
We also use a motor function sheet, which lists every input and output, which port it’s on etc., and we colour code everything. So when there’s an issue with the blue drive motor, we check all the power and signal wires, breaker and victor labelled with blue. This is all noted on the motor sheet. (It also helps software know where things are plugged in.)
The message I’d want to send my students is… be as smart and diligent as you can. Use common sense. And I would expand common sense things to include knowledge about basic electronics or shop safety or whatever.
For example - if an electronic part wants to be powered by 5 volts, then you don’t try plugging it into a 12 volt supply. (Unless the spec sheet specifically says it can handle it.) This may not be common knowledge to a beginner student, but it darn well should be once they’ve started to learn some basics.
Double-checking power supply voltages should be as ingrained as looking both ways before crossing the street.
However, given all that - I would want students to know that mistakes are OK. They happen. They’re forgivable. They’re normal. They’re a learning experience.
They do, however, have consequences - if you blow up the RoboRio, you may be asked to come up with a way to replace it. Or, the team may have to learn to adapt. You blew up the RoboRio in the practice bot. We can’t afford a new one. What will we do? Maybe build a transportable control system to move the one remaining RoboRio between competition and practice bots.
Do not drill around the electronics. Covering them MAY help but swarf (small fragments of metal and metal dust) is notorious for shorting out things when you can least afford them.
Do not trust that polarity has been followed properly, even in Kit-Of-Parts parts. Backwards wired Anderson connectors cost one of my former teams 6 motor controllers and it only took a second to happen.
Understand the safety requirements for EVERY tool and why those requirements are there. Tools are powerful and can really help build a robot but they can also be very dangerous to the untrained.
May I add that calling all of these possible mistakes student mistakes is pretty wrong. Mentors can often make the same mistakes as students counting yourself out of stupid mistakes is probably something you will regret. Personally even as a team leader I’ve made stupid mistakes. For instance after a corrected someone for cutting a piece of metal I accidentally cut to the dimension of the piece they cut earlier leaving 2 embarrassed and a wasted piece of 2x1 a $20 mistake. This is not aimed at anyone but I figured I would point out everyone should read these and take them into account.
Make sure everyone knows how to use a tool and be safe with it before using it, use common sense. Don’t use power tools around the electronics, and make sure everything is wired properly. Also, as other people have said, if someone makes a mistake, make sure that they, and everyone else who can, learn from it.
There are five key elements:
I agree with everyone else:
Supervise all tool use and any event that carries risk.
If CNC tools are involved:
(D)emand the removal of all distractions when locating or doing setup.
(I)nsist on comments in G-code or clear mechanical drawings.
®emove the tool and execute the G-code clear of the work piece.
(T)est all examples with simulation when totally in doubt.
(E)stop should be where your hand is during a dry run.
Anyone that has coolant - eventually that’s a different kind of dirty 
Here is one post on How to prevent electrical reverse polarity or connection mistakes on your FRC robot. It address specifically for power electrical.
I actually have a story about mentor mistakes, electrical polarity, and “trust but verify”.
My very first day as an FRC mentor, I was introduced to the head controls mentor and, looking for a job to give me, he handed me a package of addressable LED rope light he had just purchased from Adafruit, an Arduino board, a power supply, and said “here, take those two students and make this work”.
I guided the students through a series of “what do you think we should do next?” exercises while learning the answers myself at the same time. OK, let’s download the Arduino IDE software to a laptop. Let’s Google for the spec sheets and sample wiring for these lights. Let’s find some sample code. Let’s get some jumper wires and a breadboard and wire something together. Let’s double check everything before we turn it on. It looks good, let’s turn it on…
Nothing. It just wasn’t working. We checked it over again. Everything was wired just as it should be. Dead power supply maybe? Off to get a multimeter…
Lo and behold, the output voltage from the power supply was the reverse polarity from what was marked on the casing. The box said tip-positive but it was definitely sleeve-positive. A lot of “NO WAY!” and grumbling from myself and the head controls mentor.
So we reversed the power leads and AHA! Colourful flashing lights! Thankfully, the lights were reverse-polarity protected.
As I left that night, one of the parents came over and said “Hey, not bad for your first day!”
Usually if you put any diode backwards on a power supply insufficient to destroy it, it will simply not conduct any meaningful current. Even a light emitting diode (LED). Of all the things where you can do that - there’s a great one you can usually not destroy something.
Now if those LEDs have some crazy microcontroller - then you’d have a problem.
Watched someone do that with LED modules for a large sign once.
At $500 a module I think blowing out the module controllers wasn’t very fun.
On things I used to make that were low power I used to put a bridge rectifier in the DC power input. This insured that no matter the applied polarity the circuit always got the right polarity. Sure I lost some voltage doing that but when I found them hooked up backwards I would just say ‘there’s some part money well spent’.