Compressor Rule Question

This may have been answered somewhere but I couldn’t find it on CD from this year or in the Q&A:
Are we allowed permitted to use an off-board compressor (powered via on-board relay and robot batteries) to fill our tanks pre-match, which is exactly equivalent to a compressor on-board, then use the on-board compressor during the match, or will this violate R79? Only 1 compressor would be plugged in and used at any given time.

This is the proposed setup:

  • Prior to match, on-board relay connected to offboard compressor, connected through purge valve
  • After filling tanks, disconnect offboard compressor and plug same relay into on-board compressor

The reason I don’t see this as violating R79 is because one and only one compressor is ever plugged into the robot (effectively when pumping with the off-board, the compressor sitting on the robot is disconnected and dead weight). This would be equivalent to using the off-board as a spare part.

The reason we wanted to do this is the compressor gets extremely hot, and we want to go into a match with a cool compressor. Adding a large heatsink takes up space and weight.

I consider the setup above equivalent to a scenario in which you fill up tanks with an onboard compressor, that compressor is rendered broken, and a new, cool compressor is introduced as a replacement part prior to the match. Surely this scenario would be legal?

I would rule that as illegal as you’d be using more than one compressor. It is not the same as replacing a broken compressor because you will reuse the off board compressor for your next match.

I would also call that illegal. You can use one of large fans from the KOP to cool the compressor.

Okay, fair enough – but during practice and test off the field (in pits, etc) is this setup allowable as long as the tanks are all purged prior to onboard fill for pre-match setup? My main concern is overheating. I’m okay with running the compressor for 4-5 minutes to fill the tanks and then again during the 2.5 minute match, but while testing these compressors could be on continuously for long periods of time. Far as I know, rules pertaining to the robot config itself apply during matches but not necessarily in the pits or practice field.

The only rules in the pits and the practice field are safety. Make there’s always a relief valve and a vent valve on any pressurized system/segment.

If you think that we can violate game rules in the pits, then I should be able to have an alternate pickup arm for the practice field so I don’t break my competition arm. When swapping them out would obviously be against the rules.

I do not see the words “on the playing field” in R79. You’re only allowed one compressor. Period.


If someone sees you doing it on the practice field they will assume that you are doing it all the time.

Against the rules? If the arms are identical then I’m not seeing why your example is illegal. T8 clearly describes that mechanisms changed between matches are acceptable if they meet inspection criteria.

Still not sure why such an attitude about the compressor exists here. The rules state you are only allowed 1 and only 1 battery on the robot yet they are changed every match. Why is the Compressor not a replaceable part? This is not an attempt to gain some sort of advantage, its a safety issue.

It seems to me that having a big bag of frozen peas rest on your compressor right up until the moment you walk away from the robot as it sits on the playing field would not only allow you to start the match with a room temperature compressor, but… for what it’s worth… a cool compressor.

Heck, you could even leave the frozen peas sitting on your robot… although there may be venue specific restrictions prohibiting you from bringing food into the venue, there are no rules specifically prohibiting the use of cryogenically preserved legumes on the robot.

If overheating is a problem, though, the real solution is to solve the problem… (hmm… deep thought, that one…) perhaps by adding active cooling such as a 12V ‘computer’ fan that blows a continuous stream of air over the compressor, or by investigating ways to reduce compressor usage.



Compressed air on the ROBOT must be provided by one and only one compressor. Compressor specifications may not exceed nominal 12VDC, 1.05 cfm flow rate.


Off-board compressors are permitted, however the compressor must be controlled and powered by the ROBOT.

The compressor may be mounted on the ROBOT, or it may be left off the ROBOT and used to pre-charge compressed air in storage tanks on the ROBOT

The intent of this rule is to permit teams to take advantage of the weight savings associated with keeping the compressor off-board. However, using the compressor off-board of the ROBOT does NOT permit non-compliance with any other applicable rules.


Sorry to say, the rules seem to point out that only one compressor can be used by the robot… Yes keeping a spare compressor on hand is wise in case of failure.

I believe if you used on “off board” compressor super cooled as suggested, or had the team fanning it, then install in back on the robot prior to a match, that would be within the current rules.

Though definitely not in the spirit of them.

A lot is thought out for safety during competitions. There are many people and pressurized systems moving around the area. I remember hearing 115psi tanks exploding close by in the pits… Plastic shrapnel is a bad deal. :eek:

Plus many teams are small and vacate the pit when practicing/playing/scouting and having a hot compressor laying about getting possibly knocked over or burning a button hunter is bad… I mean buttons - You gotta gettem all…

We understand your dilemma… Here in Kona it is about 82 every day, sorry, and dealing with compressor heat, on or off board, is just what you have to deal with…

Good luck this season, and install a fan or two with some shrouding…

A good teaching moment about thermodynamics.

Not legal to use a second compressor or offboard storage.

I am not sure anything in the rules would prevent one from using a different compressor to charge the robot when you practice with it. Not saying it would be legal, but I would ask the GDC. The compressor itself is a COTS component. So you could completely unhook it, swap it out, and then swap another one back in. That is not what you are asking, but I would ask the question.

I just want to point out the wording of the rule.
Compressed air on the robot must be provided by one and only one compressor.

To me, this is different from “Only one compressor is permitted to provide compressed air to the robot” which seems to be the theme of the misunderstanding of this thread.

I interpret the rule as: at any given time, all the air in the tanks, in the cylinders, etc could have only been sourced from a single compressor. If you purge the tanks after practicing, there is no longer any compressed air on the robot so nothing was sourced from your second physical compressor.

The AIR on the robot comes from a single compressor. Not “only one compressor is permitted for usage at a given regional”.

Alas, all this is a great excuse for me to go get some dry ice to bring with me to the regional :-). Worst case maybe use the frozen peas approach. I was never intending to harm the button-hunters, as such a compressor would be well shielded and hidden beneath a massive heatsink.

Yes, this more or less is what I’m asking (or, at least what I settled on after hearing the rules explanation). “Completely unhooking” is a 2 minute job – swap the wires, swap the push-in tubing, and remount. Not a bad maintenance task to ensure a cool, healthy compressor in your matches!

From the inspection check list:
Compressor - Only one KOP compressor (or equivalent, max 1.05 CFM flow rate) may be used (on or off robot). <R79>.

Does not say one at a time. Does not say 2.

What if we use one compressor and fill up the tanks with an on-board compressor in our pit before the match, and use the same Air compressor in matches

I think the bigger issue can come in with pneumatics and the battery. If you precharge your system with a “fill” battery wouldn’t that violate R34 being that the stored air on your system was from a second battery making you have a two battery power system. If the compressor off board is the exact same as the one on board of the robot wouldn’t that be the same as switching the cost compressor between matches. It doesn’t give any advantage to the team and in my opinion it is safer due to the system being less heated. I understand that two nonidentical compressors would be against the rules, but isn’t swapping out two identical compressors the same as swapping out batteries between filling the system?

If you are using the same compressor, that is only one compressor?

Q&A Q382 seems to rule against off board air storage.

You can change batteries after charging your air tanks. If you were to ask, the GDC would probably reply that compressors aren’t batteries. :slight_smile:

And the GDC was asked, and Yes they replied, see Q88.

But no, no comparison was made that batteries aren’t compressors</humor></poetry>

Sorry, I was posting on a phone and left out an important part of my post, concerning how much the robot weighs. What I meant concerned a robot that would be overweight when the 2nd arm was added in. See R5, which is an important part of T8; make sure you understand the definition of MECHANISM when you read those. If you bring both arms in your bag (or as part of your 45 lbs) and weigh them both as part of your 120 lbs, then it would be legal to constantly swap them before and after your practice matches.

As has been stated above, compressors are not batteries. Of course the compressor is a replaceable part, but you replace parts when they’re broken, and “hot” doesn’t equal “broken” for compressors. If you’re concerned that the rules don’t specifically state that you’re allowed to have more than one battery & put in a fresh one before each match, but can’t replace compressors at will, you should submit a question to the Q&A.