Pneumatics driver (VEX-U application)

@jpearman , back in 2014 you wrote this post, giving a schematic of the pneumatics driver cable, but you said you never reverse engineered it to see what the transistor or resistor values were. Have you any update to provide?

Specifically, with the new VEX-U rules, we’ll want to interface the V5 system to industry-standard 24V solenoids. Not having a V5 to work with, would this be best through the legacy ports, using a dc-dc converter to boost the 5VDC signal to 24VDC, or is there a better way to interface through the new motor ports, perhaps using a transistor to switch a 24VDC power supply?

I have no specific update. The legacy ports should be able to drive the existing pneumatic driver cable, however, there may be some inconsistent behavior when the V5 powers on and the ports are initialized similar to the cortex. This is something that still needs to be tested and potentially improved.

You are correct in saying that the existing VEX pneumatic driver is not designed to drive a 24V solenoid, however, you should be able to find something similar using a higher powered MOSFET which would be legal under Vex-U rules. I would need to do more research to be able to provide a specific recommendation but you might want to start by reading article such as this.

That’s a really concise person-to-person (rather than text-bookish) description for switching real-world devices. It’s the sort of thing you hear in the prototyping lab during break, over a cup of coffee, as the oldster instructs the intern. The author got the tone right, all the way down to the required “we’ve let the magic smoke out”. Helpful without sounding like a lecture.