"The Little Things" - Helpful hints for all

FIRST General Forum
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The thing is, you never notice how important any one of the little things until it bites you in the bud at the worst possible time.

Final 2 at CalGames. The box in the lower right of the picture is our battery box (the real battery was still attached, we drove across the field and hung with it laying on the ground). Had we put a few zipties in the box between matches, we would have likely been able to make up the 16 points that separated our alliances, and could have taken the other alliance to a third match.

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Wow! I’m surprised there isn’t battery acid all over the place. If I can get team permission, I will post a photo of our battery holder. It was bolted on!

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-during fundraiser and off season make folks bring lunch!! and save on pizza!

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Velcro battery connector:

Robot handles from aircraft cable and pneumatic tubing (1 at each corner of the robot):

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Attaching square tube to plate using 3 roll pins and threaded rod:
(Also, identical drive plates so you can’t mix them up on assembly - left/right/inside/outside are identical)

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Quick release bumper mounts:



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Drivetrain gearbox integrated between drive rails:

Chain tensioner from off-centre drilled shaft:

Quick disconnect spade terminals on speed controller:

Surgical tubing to connect encoders and pots to shafts:

Mount PDB on spacers so you can run wires UNDER it (instead of around/over it):

89

Standard pigtail lengths on every motor w/ Anderson connectors:

Extra solenoids and speed controllers on the board:
-If a solenoid fails, we swap the tubes over to the spare solenoid and change the mapping in programming. Unused spare solenoids are plugged with tubes that have been folded over and zip-tied. This is a cheap plug that doesn’t leak.
-If a speed controller fails, we disconnect the motor from the failed speed controller, and run an extension wire to a spare motor controller. Because there are quick disconnect spade terminals on all speed controllers, this is can be done very quickly. Programmers then remap to the spare controller.

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Thanks a lot for posting those, just awesome stuff.

1 Like
91

Mr. Lim, you rock! Diggin the PDB on spacers. That’s going on the next robot

92

I’m just the messenger for a lot of these. Mr. Stehlik on 610 deserves the credit for coming up with most, if not all of these tips and tricks. The students worked out the details to do the implementations. We don’t build particularly flashy robots on 610, but a lot of these little unseen details are some of the things I’m most proud of our students for doing. It’s not glamorous work (who really wants to crimp standard length pigtails on every sensor and motor? Or machine bumper brackets?) But I think they all make a big difference, and the students who are willing to roll up their sleeves and take on these “little big things” should be celebrated.

93

Not sure how I feel about this one.

I would think the twisting slack the surgical tubing has would be a bad thing?

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There is a wood dowel inserted in the surgical tubing the entire length except for the ends that slip over the shafts.

We normally mount the encoder right next to the shaft, so the surgical tube length is very small.

This year we couldn’t do this because our CIMs were mounted close together, and we couldn’t fit the encoder between them. We borrowed the wood dowel workaround from 188, who had done this a few years prior. I was skeptical at first, but when the guys at 188 said it ended up working great, we went ahead with it too. In our implementation, the encoders are held in place by a floating encoder mount. It uses the cylindrical shape of the CIMs, the fact that the encoders are to big to fit between the CIMs, and the slight tension from the surgical tubing to hold the encoders in place.

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I’ll second that, as long as you have the surgical tubing properly attached to the encoder and the shaft it works great. We always ziptie the surgical tubing on both ends.

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The things 610 does to make the little things easier are the reason they are World Champions. Also it took me a second to determine why the PDB was not in a case. Its a beta board. But lifting the PDB is a really good idea, and I like it alot.

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I’d seen varirations of everything, but the spacers on the PDB and the redundant solenoids and motor controllers are tiny little things that really blew my mind. Those are both literally very tiny things that can make a world of difference. I’m keeping those for later.

98

Our Electrical team did a great job with their setup. However, since we had a very compact and low cog robot that can climb to the third rung and that can shoot frisbees to the high goal, our electrical board was scrunched inside the worst possible places! However, this was just a design flaw. Also, VELCRO! VELCRO is a friend!. We velcro’d many things, inclugind the bridge and the drivers. Mostly every electrical equipment except the crio and the ds. The velcro allowed us the move the electrical part to access another part. We could simply move the bridge to get full access to the shooter board. Also, our robot was quite modular. We could completely remove the shooter by unfastening a couple of bolts!

99

OK,
I have been asked to weigh in on R65 so here goes. Yes, gluing is in violation of this rule (tampering includes … gluing) but I think it is more important to look at the practice and it’s repercussions. Hot glue is ‘HOT’ by nature and the devices you are trying to glue are not. Often the glue does not adhere to the parts in the way you want so you have a false sense of security thinking the parts are secure when they are not. They just have a big blob of useless glue attached to them. Gluing connectors into a speed controller can render the $100+ part useless when someone rips the #24 or #26 wires out of the PWM connector. If the person who is applying the glue gets a little over indulgent, the glue gets down inside the device either damaging parts as it is applied or by holding in heat that otherwise would be dissipated in the atmosphere. Rapid heating and cooling can tear parts from the circuit board. The result is the same, early failure of the internal component. We have allowed teams to perform their own repairs on electrical parts but gluing parts to them makes repairs almost impossible. As I say to people all the time, “Think for a minute and I bet you will come up with a better idea.” We mount everything on perf stock. It is easy to work and all of our parts simply tie wrap to the stock. For PWM cables, we take the wire down to the deck and tie it in place. The tension holds the connector in place and a pair of wire cutters will remove both the connector and controller in the event of a failure. Gluing also makes it almost impossible to reuse the parts next year.
My Murphy’s Law corollary is “Something will always go wrong at the worst possible time, on Einstein.” You want to win and that means being able to change failed devices quickly. As posted earlier, we use quick connect tabs on our controllers. These are available in boxes of 100 from Digikey. So no other tools but a wire cutter is needed to change out a controller and you will have no dropped screws to look for. If everything is labeled (using colored tape or with real labels) then there is no thought needed to swap out a suspect part be it electrical mechanical or pneumatic.

100

An excellent idea!

Indeed: use industrial-strength velcro, and a little extra wire. Being able to pull a speed controller (or CRio, or sidecar, or solenoid, or any other electronic component) off of the robot without disconnecting anything, where it can be jimmied/fiddled-with/tightened/etc, is a godsend for fast electronics repair! And it holds up great even under competition impacts–if anything, it helps with shock absorption.

Mr. Lim’s ideas are all excellent, too. We do the additional speed controllers and solenoids thing, but never thought of mounting the PDB on spacers!

Some of 1551’s standard practices that I haven’t seen (or glossed over):

–keep a detailed inventory of what you have, in what quantity, and where it’s stored.

–clean up every night, even if you’re just coming back in the morning.

–do off-season projects that require design, and have potential applicability to FRC (manipulators, drive trains, etc). Include but don’t limit to improvements on the previous year’s robot.

–if you can’t build two robots, at least build two drivetrains, and give one to your drivers as fast as possible.

–have tryouts. Some people think they’re much better drivers than they are, and vice-versa.

–when a student says they don’t handle pressure well, don’t put them on the drive team.

–solder, don’t crimp. (Or solder AND crimp!) (Yes, I know this contradicts other advice in this thread… As two people, get three different answers! You should also have quick crimp connectors available for really fast, omg-it’s-timeout-and-we’re-in-the-finals repairs.) On that note:

–invest in a high-quality crimping tool.

–consider tensioned steel cable for upper mechanical structure. It’s very light, and somewhat annoying to work with, but can provide amazing strength and stability for almost no weight. But if you use it, use swedges with a good swedge crimper, and turnbuckles to account for expansion.

–invest in a mini-mill and mini-lathe for competition. Mount them on a cart, use that cart for (labeled) storage of all your bits and bobbins. I can’t tell you how much use these devices have seen at FLR and Buckeye, much of it for other teams–and it keeps our pit organized as well!

–build homework/dinner time into each build night, and have a quiet room for students to work until they’re done with their schoolwork; but be vigilant about off-goofing and shenaniganery!

–invite your sponsors to everything you do. Everything.

GREAT THREAD! Thanks for starting it!

101

I think most of us can agree that hot gluing your PWMs is not an elegant solution. We can put this aside and focus on whether it’s really a practice that can cause equipment damage.

This particular concern sounds silly. Your standard 99.3Sn-0.7Cu lead-free solder melts at ~440 F (PDF link). Eutectic 63Sn-37Pb solder melts at 361 F. Low-temperature “hot melt” glue guns range from 170 - 250 F.