20 minute project: RoboRIO PDP stack

This is a small 20 minute project that I did while thinking of some off season designs. My team always spends what I feel to be just a little too much time trying to fit our electronics on our bot each year. With this reason in mind, I decided to try to save some board space by stacking the roboRIO on top of the PDP. This is done with a simple aluminum plate. The roboRIO mounts to the plate with the 4 bolt holes on the bottom (4-40 screws). The plate then is stood off the PDP with 1 and 1/2 long stand-offs. bolt the PDP through your electronics board into the plate stand-offs and your set. The plate has mounting options to allow for you to mount the roboRIO in any of the 4 orientations.

PDP_RoboRIO_Stack_Adapter_Plate.step (59.0 MB)

(team Fusion360 Hype!!!)


Looks cool! But wouldn’t that make it extremely difficult/impossible to open the terminals on the PDP using a screwdriver?


there should be enough space to still get a screwdriver in (depending on the size of the tool). and if there is not, than its just 4 bolt to get the roboRIO off the PDP. I think that is a reasonable thing to have to get around if it helps give you more space on the bots electrical board.

This looks like good wire management would look awesome with this setup


My next task is to see how compact I can get motor controllers to this set up. This hopefully will be the start to making modular drop in electrical mounting solution for FRC.

Looks great for compactness. One thing to watch out for is R51. “The PDP, associated wiring, and all circuit breakers must be easily visible for Inspection.” I would expect there to be a similar rule next year, so just make sure you have a plan to make it easier to see the breakers.


good point, I had forgotten about that!


there is a pretty reasonable space between the plate and the PDP that would make seeing all the breakers not a problem. And if it’s only for inspection purposes, than removing the 4 bolts on top and moving the roboRIO off to the side for the inspectors too get a better look at all the breakers would be no problem. then replacing the plate after inspection.

The main thing for inspection is being able to quickly identify the rating of each breaker on the PDP, as well as which port they’re connected to. Removing the RIO and keeping it off to the side should work well for this. Nice design and congrats on Dean’s List :smiley:


Wait is there space to pull our and put in fuses with out having to take it apart?

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probably not. you could in theory flip this around and stack the PDP on top of the roboRIO, but then wiring could get ugly and it would be harder to see the diagnostic lights on the roboRIO.

Yup, this would be my concern too! The rule requires circuit breakers should be easily visible (something to that effect). Another concern is electrical noise generated by PDP. If its aluminum plate under the roboRIO, noise may not be an issue.

Nice job though!

I remember finding some similar ideas on thingiverse a while back, so I went through just now and made a collection in case it helps anyone else spark ideas. https://www.thingiverse.com/gixxy/collections/frc-controls-organization

Also plenty of other FRC related items on Thingiverse, using FRC and First Robotics as search terms.

this is our electronics board from this year


Just remember, the cables have to allow this!

I had to inspect a team that put a bundle of motor controllers (I think 8 Talon SRXs) right above their PDP with no cable length to move it very far.

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548 tried this idea last year and it really got annoying. It didn’t help that our robot made it difficult to get to the RIO, but stacking it made it worse. It’s also harder to strain relief the RIO wires. I’m pretty sure we ended up with only two screws after a few weeks. It seems like a cool idea, but I’d try to avoid it.

This ^^^ is the key part! If there is no extra cable, especially the power cables, you know the issue. On the other hand the wires going to roboRIO are thinner (16+ AWG) , you can keep them longer and nicely tucked in to make it easier for moving roboRIO to one side or the other for inspection.

… then what happened? I am sure you would not pass inspection without checking the breakers, would you?

What was that pump for?

I had them cut some of their “cable management” zip ties to allow some more movement, which was only an inch or so. I ended up having one of them hold it up while I checked their entire PDP (and found two wires in one port, so they had to fix that). I then had a short talk with them about planning better next year.

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