How Can I Avoid Student Mistakes
 

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!!!

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

Electronics:

red to red, black to black, and make sure power input goes to the input side of motor controllers, not the output side

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.

- physically dropping it
- plugging it into the wrong power supply voltage
- plugging it in with backwards polarity
- electrostatic discharge causing damage
- connecting it to another device incorrectly (backwards)
- connecting power to a signal connection

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:
- Are my safety glasses on?
- Are long hair and clothing tied back?
- Is the piece properly clamped down?
- Is the bit properly tightened in the chuck?

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.)

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

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.

Re: How Can I Avoid Student Mistakes
 

There are five key elements:

• Training, including regular refreshers and safety stand downs after close calls
• Supervision, really close for the first few hours, backing off slowly
• Verification, first by another student and again by a mentor
• Mitigation, including safety glasses, fire extinguishers, and spill kits
• Prayer, left as an exercise

Re: How Can I Avoid Student Mistakes
 

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.
(R)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 ;)

Re: How Can I Avoid Student Mistakes
 

Here is one post on How to prevent electrical reverse polarity or connection mistakes on your FRC robot. It address specifically for power electrical.

http://www.mindsensors.com/blog/how-...our-frc-robot-

Re: How Can I Avoid Student Mistakes
 

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!"

Re: How Can I Avoid Student Mistakes
 

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'.

Re: How Can I Avoid Student Mistakes
 

The Dlink's are especially vulnerable. We have burned out more than our share of routers. Most of FIRST's equipment has reverse wiring fault protection. But, the Dlinks do not.

So, ANYTIME the wiring of the Dlink power cord is changed (even if it is just disconnected and reconnected), I make the students verify polarity and voltage with a volt meter before they can plug in a Dlink. The power cord is not color coded, so it is easy for the students to wire incorrectly.

Re: How Can I Avoid Student Mistakes
 

One big one is gaining and maintaining the student's respect. This is a mixture of enforcing rules/behavior policies but also building rapport. Too much enforcing leads to students who behave in front of you but develop a common connection of not really liking you. Very unlikely to behave when you aren't around. Obviously being too soft and "fun" causes them to disobey rules right in front of you.

Don't be afraid to joke around with students.

The other big thing is letting them know that if they DO break something that they should feel comfortable telling you so the problem can be fixed. This goes back to my initial comment. If they are terrified of breaking something, they will only hide it when they do. We have all broken lots of things....usually professionals have epic stories of screwing up.

As long as something really, really dumb didn't cause it, I don't get worked up. They don't need a long lecture to know not to do that thing again. Especially if they have your respect, they'll feel the worst about letting you down.

And, then again, I've done plenty of really, really dumb things myself in my day...

Re: How Can I Avoid Student Mistakes
 

Thanks to everyone for all the great tips. I will be using lots of these suggestions. I'm especially thankful to know that sometimes the equipment has reverse wiring and I will make sure the students and I check the polarity of each piece.

Great blog pnitin. I'm sure this practice will save us some money and probably a few headaches.

Re: How Can I Avoid Student Mistakes
 

There is a follow up to pnitin's post on our website. Detailed instructions on how to solder the XT60 connector can be found here.

Re: How Can I Avoid Student Mistakes
 

I like many of the suggestions on here. As a mentor might I just add a couple of other things not mentioned.

I tell kids that nobody plans mistakes, but they happen. Especially when people get tired. Which pretty much defines FRC. Double check, and watch where you are if something goes wrong. Drilling on your lap is not acceptable practice. Neither is drilling on someone elses lap. (both seen).

Sometimes you just need to walk away. To say our budget is tight is an understatement. Everything we buy is a choice between things we need. A couple of years ago I had a student wire a brand new camera backwards. Brand new... Just out of the box. We had saved for the camera and it was destroyed instantaneously. I just walked away. There just wasn't words. It has become legend.

Nothing is worth getting hurt. It's easy to start taking short cuts when time is tight. Don't. Disable and dissipate. Watch for stored energy. I had a kid reach through a drivetrain (chain) on a live robot. One of the few times I screamed at a kid, legend. It was truly fear and addreneline on my end.

Teach kids to measure. Close enough is not good enough. A marker is NOT a layout tool.

Good luck!

Re: How Can I Avoid Student Mistakes
 

I am a Student on a team out of Kansas and last year I wired the new control system, told my mentor to check it, they said green light. Okay sweet! Plugged in the battery flipped the switch... Smelled smoke and my reaction was "Thats not my fault". (FYI It was my fault!) That day I learned to check that black wires are negative and red are positive I had the + and - switched on the PD board and fried the $200 board. I still get crap for it (But refuse to say it was all my fault my mentor checked my work!) I did learn though! :D

Re: How Can I Avoid Student Mistakes
 

Could've sworn with wiring it was red goes to black you're okay jack red goes to yellow you're a dead fellow.... weird.

Anyway you can only avoid student mistakes for so long and that while mistakes in FIRST can be costly they are still a chance to learn. Mistakes in the work environment just suck and mean you should make sure your resume is up to date.
Anyway my preference when dealing with situations where people are going to have to be around hazardous equipment is simple. Take the information they need to be informed, and to be safe, and give it to them. It is also a condition too when it comes to heavier tools, if you aren't going to be safe you aren't going to get to use the stuff. Some safety that you might not think about but definitely are like the bane of my existence are allergies. Keep the work space you have clean. One of our Alumni happens to have a rather serious peanut allergy, and when he was on the team I remember so many times stopping people after seeing them eat and going "wash your hands." The more you know the small details on a team the more likely you are to prevent something from happening all together. Some students you need to tell to go on a break, or eat something, and don't be surprised if students tell you to do the same.

Re: How Can I Avoid Student Mistakes
 

Ones chances of this sort of thing happening would be much, much lower if one adopted the attitude that when one is presenting ones work to be checked, that person is being challenged to find any errors because the work has been checked, double-checked and triple-checked and all errors found have been corrected. The other person should be there to confirm that the person doing the work has found all of their own errors, not to find the errors for the person doing the work.

Re: How Can I Avoid Student Mistakes
 

Agreed!! Unless of course you get a Talon that has the wrong color wiring on the controller. The GND had the red wire, and the V+ had the black wire. Luckily we caught it before it was ever hooked up...