Pneumatics during disabled Mode

Hi. My team’s bot is too big normally, but when the pneumatic claw is down, it fits in 18 by 18. is it possible to start the match with the claw being down, and if so, how? Thank you for reading.

If you initialize the Digital Out (solenoid) with an initial value of “true”, it will cause the piston to start the match extended once you start the program. However, during inspection, when they’re checking your robot’s size, you can’t have the robot on, so I’d recommend having an air flow valve (the light grey rectangular prism with the baby blue switch) so that you can toggle the pneumatics on and off. If you toggle the air off, it will make it so that you can manually extend the piston, allowing your claw to stay in size during inspection.


gotcha. I have single acting pneumatics, so I do not know what I can do for that.

Also wont digital out not work during disabled mode?

It does, you just have to set the state while defining the Digital Out. I believe it’s one of the parameters you can give when defining the Digital Out alongside the 3-wire port that it’s plugged into. At least, this is what I’ve experienced in PROS; not sure how it would be in other programs.


It’s possible you could use a rubber band to artificially extend the piston for inspection, and then just extend the piston electronically before matches. I believe a rubber band will be enough to stop the piston from retracting.


just inspect without air in the tank
but i always use double actings so your mileage may vary

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The “unpowered” position for single-acting air cylinders is retracted, because of their internal spring. In the same way, the “unpowered” state for a single-acting solenoid valve is to vent the air cylinder to exhaust. This is a disadvantage of single-acting cylinders, that users of double-acting cylinders don’t have to deal with: With a dual acting cylinder, the solenoid valve in it’s “unpowered” state is still applying pressure to one side or the other of the air cylinder, giving you the choice of extended or retracted for the air cylinder in the unpowered state.

Inspection and the start of a match will both require the robot, in the unpowered state, to pass inspection. If you require your single-acting air cylinder(s) to be extended when unpowered, you might need to develops some sort of passive latch mechanism to hold things to a legal position prior to the robot being energized during the match.


I think you can switch the R and P values of the solenoid for the piston, which will switch the default position.

Are the air flow valves (grey prism with baby blue finger switch) mandatory? In other words, is it competition illegal to have robots without them? We took them off as to minimize the amount of connections and air leak points (ahem… also someone forgot to turn them on in a competition… ahem…) Someone at a recent tournament suggested we should have not passed inspection, but the inspection sheet only asks if all parts are VEX obtained and if we use more than the 2 allowable air tanks. What says the community? Thanks.

Yeah there’s nothing in the rules that says you have to have an air flow valve/shutoff valve on your robot. (hopefully I didn’t just say something dumb but I’m 95% confident in my answer.)

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Thanks. Yeah, I searched through the rules many times as well in order to not sound dumb.

Maybe what you can do is tie a rubber band to the claw, then a rubber band to something on the axel you use for the drive train motor. When it starts moving, the rubber band will fall off, letting the piston go

You don’t need them, I recommend not using them unless it’s for testing because people forget to turn it off or it gets hit by something and now no pneumatics