pic: roboRIO Connector Board



The main reason for this board is to simplify connecting industrial sensors that require a 12V supply. The last four digital sensor ports are powered with 12V from the VRM. Either NPN or PNP sensors can be used, with locations for pullup resistors or a voltage divider. I also took the opportunity to convert all of the connectors to weidmuller terminal blocks since PWMS are so finicky and can get pulled out easily. Note this is not an expansion board so the MXP port is left open. Eagle CAD files can be found here:
https://drive.google.com/open?id=1Lik8zv92FlVuCJ-YqQ6eyH9hvjoqbVyO

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What an amazing idea. Where can a team order one or two or three of these. Quick disconnect your Roborio. Robot is Bagged and only have one Roborio. No Problem.

Market this. Having the opportunity to use push-to-connect rather than having to crimp all the wire ends into connectors is outstanding.

I like the idea & clean implementation.

Are there labels for pinout somewhere on the silkscreen (power, ground, signal)?
I don’t see any, but could just be hidden behind a connector in the photo. I’d assume the same orientation as the stock connectors, but that’s obscured by the PCB when its mounted to the RIO.

Ha! I was going to make something like this but with M12 connectors over the summer, but I couldn’t find a way to package it and I had to go back to school.

Are you planning on selling those through a COTS vendor? Or remaking the board for the competition bot?

Does this comply with R73?

Presumably the team would be able to show that the board connects those required items through passive conductors only. Real easy if there aren’t any chips on the board, and if you have a second one off the robot the inspector can handle. Once you show it’s all passive conductors, the argument for allowing it is pretty easy, I think. Of course, asking on the Q&A is always a good idea if there’s any doubt.

I would buy this so fast.

For reference.

R73. Every relay module (per R34-B), servo controller, and PWM motor controller shall be connected to a corresponding port (relays to Relay ports, servo controllers and PWM controllers to PWM ports) on the roboRIO (either directly or through a WCP Spartan Sensor Board) or via a legal MXP connection (per R74). They shall not be controlled by signals from any other source.

That parenthetical “(either directly or through a WCP Spartan Sensor Board)” is a little troubling. I could see a team’s argument that each connection is direct working with some inspectors, but I could also see a team drawing that inspector and getting the opposite result.

But man, I didn’t realize how much I want this in my life.

I might recommend adding another set of male headers that pass through just like the Weidmuller connectors, to connect motors/sensors that already have the corresponding female header installed (i.e. PWM cables to motor controllers).

Other than that, looks good! I like the PNP/NPN sensor selection and mounting point for the NavX micro. Would be cool to have an I2C passthrough for the NavX micro to make the board 100% swappable.

In 2015 there was a girl by the name of Roshni on Team 1717 who worked with her mentor to design a board with very similar intents of securing connections. It was very well done. I wish I could find a picture of it.

What an amazing idea. Where can a team order one or two or three of these. Quick disconnect your Roborio. Robot is Bagged and only have one Roborio. No Problem.

Cool! I hadn’t thought of it as a way to save on roboRIO’s but that makes a lot of sense. There are a lot of pins to disengage, but if you pry at it carefully from each side, it does come off relatively easily.

Market this. Having the opportunity to use push-to-connect rather than having to crimp all the wire ends into connectors is outstanding.

Maybe I could get AndyMark to sell them… We certainly aren’t looking to become a first approved supplier.

Are there labels for pinout somewhere on the silkscreen (power, ground, signal)?

No, there wasn’t much room for labels. I plan on making a 3D printed cover that would incorporate labels somehow. I think just marking the white buttons on the terminals to color code them would probably go a long way. The outer row would be black, the middle red.

Are you planning on selling those through a COTS vendor? Or remaking the board for the competition bot?

I had a few boards made. I’ll get one of our electrical guys to do the soldering on a another one during build season.

Does this comply with R73?

The wording in this rule is troublesome, so if a lawyer was reading it, probably not. R74 B says passive extensions of PWM ports are fine, but that is specifically referring to the MXP port. They probably didn’t forsee someone wanting to extend the existing PWM pins.

I might recommend adding another set of male headers that pass through just like the Weidmuller connectors, to connect motors/sensors that already have the corresponding female header installed (i.e. PWM cables to motor controllers).

Not sure about that, the main purpose of this board is to get rid of PWM connectors. I agree not everyone would want to cut the connector off of a PWM cable that is built in to a speed controller, but it does offer the advantage of a more secure connection. Conceivably someone could just install a header socket with extra long pins that would serve as a connection above the board.

Other than that, looks good! I like the PNP/NPN sensor selection and mounting point for the NavX micro. Would be cool to have an I2C passthrough for the NavX micro to make the board 100% swappable.

Good point! Kauai labs recommends USB for the NavX micro, so I didn’t even think about i2c or RS-232.

Agreed! This could be done with no changes to the circuit board, by using stacking headers. You would want some sort of protection for those pins, though.

Hmmm. Unless the bare board is COTS, this won’t be sufficient to meet (last year’s) fabrication schedule rules. You may need to make another order soon after kickoff, and swap it onto your competition robot before March.

Please don’t let this detract from all the positive comments here. What you’ve made is really great!

There is no R73 issue as this item is just a connector.

Does your answer change if the transistors are populated? Since you seem to be applying the passive rule from R74 (that I’m not sure applies), then adding an active circuit would definitely make it illegal.

The WCP Spartan Sensor Board extends PWM pins and is explicitly exempted. That seems to set the precedence that it’s not legal unless specifically approved.

Hypothetical for you to consider… Say a team has a removable mechanism. On said mechanism is a speed controller. They connect the speed controller through some PowerPoles or Molex connectors (or whatever) to existing wiring on the rest of the robot, connecting it to both power and the RoboRio this way.

Is that legal per this rule?

What about taking the victor SP, cutting the PWM cable in half and soldering a length of wire in there to make it longer.

Is that legal per this rule?

Now, lets take an another controller, like a Victor 888. A team makes their own custom PWM cable. Crimps the wires, sticks the pins in the headers, etc.

Is that legal per this rule?

In all of these cases, you’re adding passive conductors, which (I assume) is what this board does. Does it make a difference if those passive conductors are on a PCB?

For this, I’m looking back to a blog post from 2014 that explained the reasoning behind the MXP restrictions.

As soon as you decide to use those PWM pins to cause robot parts to move, you’ll have to use an approved device that FIRST has pre-vetted and listed in the manual as legal. This is to ensure that when those 10 pins are disabled, that disable signal that’s so important to us isn’t obscured or interrupted. It’s also an attempt to keep the inspection of that clean, simple, and objective.

Given that explanation and extending it to this situation, if the board was completely passive I’d say it’s legal. Add on anything but passive conductors and it isn’t. We can’t expect every inspector to be an expert on PCB design, nor to take the time to ensure that an active component on one side doesn’t affect a passive component on the other.

I know, this device is for the PWM slots, not the MXP. But I think it’s reasonable to extend this same reasoning.

Fantastic, 610 never disappoints.

Hmmm. Unless the bare board is COTS, this won’t be sufficient to meet (last year’s) fabrication schedule rules. You may need to make another order soon after kickoff, and swap it onto your competition robot before March.

True, I should get a list of teams that want a board and make an order for new ones right at the beginning of build season.

Does your answer change if the transistors are populated? Since you seem to be applying the passive rule from R74 (that I’m not sure applies), then adding an active circuit would definitely make it illegal.

There are no transistors, only resistors. And these are for the sensors, not the PWM outputs.

Anyway, I’m left wondering how one would proceed in getting a custom board like this approved. Who at First HQ needs to give this a thumbs up? Can someone here with experience in this area point me in the right direction?