Pros and cons of electronics boards/boxes

[RbtGal1351]

I'm investigating the pros and cons of electronoics boards and boxes. I'm in charge of 1351's control systems and I'd like to have a good idea of how to organize the electronics before build season starts. I've read most of the threads and seen the pictures of other teams boxes. (especially this thread)

However, will somebody please follow up and say how these "awesome" boxes and boards actually worked in competition? What were their flaws? Benefits? What is the advantage of having a box/board as opposed to simply mounting all the electronics the bottom of the chassis in an organized pattern?

I realize these questions are vague, and I apologize. A list of pros and cons for a specific idea, (comparing it to other ideas too) would be good.

Thank you!

~Stephanie
Team 1351
Control Systems Leader

[Billfred]

This year, 1293 had a board on Ockham for electronics. Imagine a big piece of aluminum bent 90 degrees. The RC and breaker panel were mounted vertically, with the Victors (no Spikes) on the bottom. Throw in some nifty water jetting to save weight, and you've got a right purdy electronics board.

The one problem I've experienced with it is that it's sometimes hard to get into there to work on the Victors, as we put it nice and deep inside the robot. (If you look at this picture, it's between the tower with the van door motor and our arm covers. The triangular hole is from a piece that both anchors our arm and shields the electronics.) If I could do it all again, I'd try to remove some more weight, and perhaps come up with some other mounting scheme, probably a bit more exposed with protection.

However, it does allow you to get everything out easily enough, once you disconnect the wires. We've never had to do it, though--clean living, I suppose. I'll try to get a picture of it this weekend.

[Greg Needel]

in my opinion the electronics should be:

*protected
*easily serviceable/ removable
*visible
*placed centrally to minimize wire runs


other then that it really is the sky's the limit with creativity, although it seems that alot of the time the electronics are an after thought.

[KenWittlief]

the benefit of having your electronics enclosed is protection from arms and other metal parts of other robots intruding into your robot, and shorting out your control systems, or burning up your wiring. A short circuit during a match can destroy your electronics, and you only have so much time between matches to replace them, esp in the final rounds.

the downside is this makes it more difficult to access the components, and you need to make sure you have adequate airflow for your Victors (cooling).

[ttedrow]

Others have already mentioned the advantages for an enclosure. You must also remember that the space available for you box may be limited by your robot design and function. So, that nifty box that you spent hours designing with quick disconnects and extra components gets scraped the night before shipping because it does not fit or weighs too much.

[sciguy125]

This leads me to question what industrial machines do. I suspect that the "brains" are centralized. But, what about drivers and other low level control systems?

[ttedrow]

Originally Posted by sciguy125

This leads me to question what industrial machines do. I suspect that the "brains" are centralized. But, what about drivers and other low level control systems?

The answer to this takes a lifetime to learn and is continuously changing.

[KenWittlief]

Originally Posted by sciguy125

This leads me to question what industrial machines do. I suspect that the "brains" are centralized. But, what about drivers and other low level control systems?

one answer: pop the hood on your car. Check out the fuse box, the ignition control, the sensors, the wiring harnesses.

many electronics are potted in epoxy or silicon.

[Mr. Lim]

Hey Stephanie,

I'll share our experiences with 188's "Trap Door." Every year, several things go wrong with the robot, and inevitably you have to do some troubleshooting, or some rewiring. We had to add a spike to our setup because we had to switch some single solenoids over to double solenoids in Pittsburgh.

We probably couldn't have done this without missing a match if it wasn't for the trap door accessibility.

There are always improvements that can be made however:

1) Both the top and bottom layers were made of wood. This was really light, made mounting components easy, but by the end of the season, our bottom board was smashed up pretty good. We'll probably use lexan for the bottom board this year.

2) Disconnects to every motor.

3) Better wiring diagram, right on the board.

[Tom Bottiglieri]

I'd say it really depends on the system you feel will fit the best come build time.

Example: Our base is made of wood. It would be a waste of space and weight to make a seperate box for electronics when we can easily mount them right to the wood.

[lukevanoort]

We had a wood board between the framerails to mount everything to. We just stuck the RC directly on it, and mounted the breaker panel at a 90 degree angle to it. Ours was safe from everything except our arm, which we stuck a microswitch on to protect the boards. I also saw a team at VCU that had their Victors on the underside of the robot, upsidedown. We though they'd have dust problems, but it seemed to work fine.

[sciencenerd]

Team 1318 decided to go with a wooden board mounted a little below the main chassis, attached to the bottom of brackets. That way, when we needed to access it, all we had to do was disconnect everything plugged into it, take out four bolts, and (carefully) lower the board to the ground. Maybe not as ingenious as, say, team 116's box, but it was easy to access, and all the electronics were right there when you pulled it out. The only problem was our arm, if a driver pushed it too far the prong for lancing tetras could hit the RC. Luckily that never happened, but in retrospect, it would have been better if we would have put a clear plastic sheet over the board in that part to make it a little more robust.

[Gdeaver]

No matter what the design, I would put protection first followed by access and service. In any design consider how fast a vector, pwm cable or other part can be replaced. In back to back matches you may have not more than 5 minutes to accomplish these tasks.

[John Gutmann]

A few years ago on our robot we haev the electronics all on one board in the middle of the robot( the game with the bins) and they were impossible to get to, until you found out that if you turned the robot on the side the whole board had a hinge on it so you could flip it out the bottom to service it. If you do something like that make sure you have enough wires so that you dont have to disconnect them when you fold it out.

[Cuog]

One thing our Team(422) has done is a modular Circuit board that can be easily removed in about five minutes. This was for mechanical issues and at the VCU regional this year it allowed us to get to our motors and save a gear bfore it died.

For a box i would recomend looking at pictures of the insides of computers and looking at how they are set up:
-Bundled wires are your friends for organization
-logical placement and no wiretangling is a must
-COOLING chips create heat, motor controllers create heat, LET IT GO SOMEWHERE, FIRST gives you muffin fans use them! if you don't cool a box your victors may shut down on you because they got too hot during a match.

And if u have some extra wieght make a water cooling system and cooling blocks, I'm trying to get my team to do this but its still a no go