[POLL] Electrical Board Design/Placement

Haha, not much.

Here’s an album with a few pictures from each of our boards over the past three years. (Annotated in the pictures description.)

In some of those cases it comes pretty well flush with the bottom of the 1x1 tubing we make our frames out of. We affix a polycarb panel to the bottom of the frame to keep it protected.

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On our 2018 robot Dropkick (RIP), we made an upside-down t-shaped structure with the battery on the bottom, and the PDP and RIO on the two sides of the “T”. this sat in the back of the robot with the PDP facing out the back. This let us see everything and troubleshoot as well.

it’s hard to see in this picture, but the RIO is right behind the middle air cylinders. Since our bot relied heavily on pneumatics, we made the two “wings” (with the NASA logo) to mount the solenoids and other accessory parts on.

I mentioned to a couple people recently the idea of having our electrical board on the underside of our bot and a question came up. How do you easily access the board? Sure, you tip the robot over, but is there an easier way?

If you can mount it upside down with a lot of open air around it then yes but if it needs to be closed off you will most likely have to tip the robot unless someone else has some ideas

As I said in my first post if you have the space I would mount it in a more open space on top of the robot just for ease of access if you have an emerging or something

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That describe our 2019 robot perfectly. Basically, it was ‘here’s the space we have’.

I’m a big fan of working in some vertical mounting space. The pass-through this year basically made that impossible.

The teams that I’ve seen doing upside down electronics (my team included) usually just opt for tipping the robot on its side to access the electronics. It’s actually pretty convenient, at least compared to reaching under mechanisms mounted on the robot.

Two suggestions.

Help your team learn how to make reliable connections of all types i.e. crimped, screw cage clamp (RoboRio power), spring clamp (Weidmuller &Wago), bolted (PDP power in & SPARK motor controllers), PWM, soldered etc. The team should also learn how to verify the quality of each and every connection. Good quality connections will have a much lower probability of failure, reducing the need to flip your robot over.

Install the electronic components on a panel that is easily removed so it can be pre-assembled AND pre-tested outside of the robot before being installed. You will have to add connectors to the wires between the motor controllers and the motors, the wires to any sensors and the wires to any solenoids not mounted on the panel. The only wires you should not add connectors to are the ones connecting the battery connector and main breaker to the PDP. Adding connection points increases the overall chance of system failure. For many teams, this is more than mitigated by increasing the quality of the connections.

If you do mount all of your electronics upside down I would say don’t because then it is very difficult to see your indicator lights to see what issues you have. I know from experience

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Mounting your electronics panel on the bottom should be a last resort, even though it can be made to work reliably. Even with a pass-through design, it should be possible to find or create a place for a vertical surface to mount the electronics panel. It may be necessary to adjust your frame perimeter to make this space.

We just started using this setup. Like it so far.


@Kaitlynmm569 Thanks for making this thread! I really appreciate this kind of discussion about designing the parts of FRC robots that don’t get discussed and planned enough.

I have a question about electrical board construction and placement: what are people’s views on mounting the board in the belly pan and using standoffs to elevate components to allow room for wiring (and good wire management).

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In U shape in a box with doors

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My team did something similar this year. We didn’t mount our board on the belly pan, but we did have standoffs. Our board was mounted upright right behind the elevator. We had two panels, attached with standoffs. The panel closest to the elevator had our motorcontrlers and pneumatic air tanks. On the panel facing out of the bot, we had PDP, VRM, PCM, the rest, essentially. We then used that in between space between the two boards to run pneumatic tubing, wires, mounting some solenoids. It worked great. It did get quite cramped, so you either had to have small hands, or not care if reaching in was a struggle. All in all, the board worked great.

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That’s a good plan, but make sure of two things:

  1. Allow enough space to potentially have to fish new wires in and old wires out,

  2. If you have a machined/routered belly pan (like many teams do now like 254’s) make sure that you break the edges of the grid, otherwise they become razors for the wire. Additionally, it’s even better to powder coat the pan after breaking the edges so they are not so sharp.

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Have you actually built this, installed it in a chassis and run all the wires?

How do you prevent the wires coming out of the VRM and PCM from obscuring the ports on the RoboRio?

How do you secure the wires coming out of the top of the motor controllers? What happens to the wires coming out of the bottom of the motor controllers?

Is the intent is to run the wires in the space between the electronics panel and the belly pan? You will most likely have difficulty reaching into that space to strap down the wires and end up with a “birds nest”. This will also make it difficult to make changes and repairs quickly at competitions.

If you remove the panel to secure the wires on the back side, you will have to add connectors in all the wires. You will also have to allow space along the sides of the panel for the connectors. In that case, you may as well not run your wires to the back and use the space for connectors to run the wires.

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Yes yes yes. There is room enough between the roborio and other components. The bottom wires go to the PDP.

841 runs an “everything in the WCD-style bellypan all the time” model, which makes it easy to swap Major Mechanisms.
Architecturally, we run small robots, around 28" a side, and we’re pretty much at the limit of fitting controls (+pneumatics) into a single 2D flat plate bellypan; to go any smaller, we’ll need to embrace “thinking in 3D” when we do our layout with some of the ideas in this thread.

We used this concept to sneak our PDP main wiring underneath our roboRIO, so that our batteries and gearbox could counterweight the forklift/elevator end.

Then we put the elevator bottom beam across the top of the roboRIO.

Then we had to pull the roboRIO at one of our competitions. That was not fun at all. 10+ minutes. The standoffs were NOT easy to get sorted back out in place. If I had to do it again, maybe a 3D printed single part chassis to create the standoff effect?

I liked that we cut ~6" out of our main power run by not having to go around the RIO, but I would be hesitant to implement it across the design, because the more wires are hidden the more difficult it is to inspect for sharps & shorts, and standoffs are /fiddly/ to reinstall with a Major Mechanism in the way.

Clean sheet, I’d rather move to a bellypan with a battery-pdp-rio-gearbox setup than our chosen battery-gearbox-rio-pdp setup, and explore 3D mounting options.

Ours was upright on BOTH sides. Not the easiest thing to work with honestly.