Ethernet port on robot

Ok, so my electrical peeps have posed a question and before I say ok I would like to know if anyone else has tried this.

They want to mount an Ethernet port on the bot. The Ethernet cable on the backside would lead to a port on the cRio and be ‘permanently’ connected (i.e. there would be no need to plug and unplug this cable from the cRio).

The idea is that when the coders needed to upload code they would do so through this port instead of having to, ‘reach inside the bot where there are sharp pointy things that can poke and scratch the coders’ sensitive hands.’

I have searched CD and have not seen where anyone has done this and according to the peeps interpretation of the rules this would fall under a ‘custom circuit’.

I have told them that I was first going to check CD and then post in Q&A before I would consent to their experiment.


Not sure if this is what you mean, but last year we ran an Ethernet “pigtail” (male to female) from our radio to an easily accessible spot for ease of access to a port. Worked quite well at competition.

Maybe…ok, I see what you’re talking about (thank you Google). What they are actually talking about is the wall-jack itself (like you see in a wall where you plug in your Ethernet cable. In their minds they would physically wire the jack themselves with the RJ-45 end plugged into the cRio and the port available for plugging in the computer.

What you guys implemented is makes more sense logically.

If you’re concerned about it working properly: it should be fine. We’ve used similar setups for the same reason over the years, and they’ve worked well.

If you’re concerned about rules: a) you won’t be connecting from the ethernet port to a computer during competition unless you are changing code at competition. b) R56 says that the wireless bridge may be connected via a pigtail, which is what it sounds like you are using.

Either way, you should be fine.

Thank you for the quick replies :]

How would the radio be connected to the cRIO in this scenario?

you can have a spot where the pigtail is out of the robot. Ie what spectrum did in their drive train during the off season. This allows for an easy remove/install for the cable. See they did what I think you are speaking of.

I would put the pigtail in the router if your using the crio II.

I would recommend doing this not only on your robot but your driver station as well. That port gets frequent use and my team had actually experienced the Ethernet port on the laptop fail causing us not to move in a match. Here is a company associated with FRC that sells the one that we now use

Agreed. We beat up our Classmate ethernet pretty badly, so when we got a new laptop, we made sure to use a pigtail for the connection.

There are enough things that can go wrong without worrying about the ethernet port…

Can we have the radios on in the pits? I thought not but maybe that is an old rule. We always hook up a little 4-port bridge for pit access - that way we can hook up the cRIO, tether the DS and connect a code development laptop.

In 2012, we used one of these port savers to easily connect to the robot, since the ports all pointed down on the radio in a most-inconvenient way.

As to radios in the pits:

Wireless ROBOT control is only permitted on the FIELD or Practice Field. ROBOTS must be operated by tether when outside the FIELD or Practice Field.

We’ve had an externally available port for a number of years. Typically we do it with a female-female connector designed to be mounted through a surface - just cut out an appropriate rectangle in one of the lexan shields, push it in until. It clicks in place, then hook it up permanently to the radio using a short Ethernet cable. The benefit of this over a wall jack is that you don’t have to mess with the wiring - just use standard cables and it all works out. I hate cutting open an Ethernet cable and having to figure out where all 8 wires go!

You can have the D-Link powered on in the pit, as long as you leave it in Bridge mode and don’t try switching it to AP mode. You are encouraged and expected to leave everything connected on the robot, and plug in your programming computer and/or Driver Station using an available D-Link ethernet port.

Which is what we have typically done. I am not sure where they are talking about burying the router that this is necessary (we have not fully discussed their reasoning yet as they proposed this close to time to go home last night). They just kept saying, ‘but it would be soooo much safer’.

Thank you to everyone who responded and we will take your suggestions under advisement.

It is safer… a few years ago before we started doing this, our programming team managed to bust enough of the ports to kill 2 radios, just through practice/test while tethered on the practice field. With an adapter in the middle (properly supported, of course), you’ll bust the adapter, not the radio - and the adapter only costs a buck or two.

Last year we tried something new with great results. We ran a wire to the back of the robot, nearest the programmers in the pit, and used a punch down network jack. We velcro-ed it down. We have always had problems in the past with people tripping over the wire and breaking something important. With this method they just yank out the punched down wires, which can be quickly punched down again.

Yikes - We have been too restrictive in the past. Thanks Alan! Your posts are always most helpful.

FWIW, burying the radio is probably a bad idea apart from the Ethernet cable(s). You have to take it out to have it programmed with the security key for the event, the lights are supposed to be visible when on the field, and it may not work as well when surrounded by metal and/or near things like motors and the power converters…

This is more of a bad idea from the standpoint of connectivity than that of damage. The AP has two antennas that communicate with the field wireless router. It needs both of the antennas in the clear, away from noise generators and metal, to maximize bandwidth connection in both directions. Low and inside is good for baseball and bad for the AP.