[FluidNC Issue#1507] Feature: poll sdcard cardDetect pin and take appropriate action when inserted or removed.

#1 – MitchBradley 于 2025-06-03

“The web interface” is actually two versions, only one of which the FluidNC developers control. “Any machine that has a card detect pin” excludes all of the controller boards from FluidNC developers. To my knowledge, no controller board with a card detect comes from a vendor that supports the FluidNC project in any way, so supporting the feature would only increase our non-compensated costs in supporting products that are “free riding” on our development work and ongoing help for users.

There are many things to consider, including when it is safe to perform such a check. Doing it in the midst of sender activity could disrupt the running of a GCode program. There is a probably a way to do it safely, but finding all of the edge cases could take a long time, especially in light of the small percentage of boards with the capability.

My personal take is that the value of the feature across the user base is not worth the costs. If someone else is willing to undertake the project and see it through to completion, and offer ongoing support for it, I would be happy to consider PRs to implement it.

#2 – MitchBradley 于 2025-06-03

There are other states to consider, such as “card inserted but cannot be read correctly”. That adds additional user interface complexity.

#3 – ellensp 于 2025-06-04

After this response, am I no longer going to use FluidNC, as the developers seem to me to be incompatible with opensource philosophy.
Seem more like a Ferengi mindset. All about profit.

#4 – MitchBradley 于 2025-06-04

Actually, it is all about time management. If you add up all the revenue and divide by the number of hours spent developing and supporting FluidNC and various other ecosystem components like pendants and IO expanders, it comes out to much less that $1/hour. Since we have too few hours to do everything that people ask for, we choose to do things that, in our opinion, would have the most benefit to the most people, with as little as possible impact on our already-overwhelming support burden.

I have been involved in Open Source work since before it was called that. I would suggest that it is you who do not understand the philosophy. In the earliest days of the movement, the founding philosophers made it clear that free software is “free as in speech, not as in beer”. Read up on the history of Cygnus Solutions. Also consider that fact that the vast majority of Open Source projects are abandoned sooner or later, often as a result of developer burnout. We are trying to keep this one alive, maintaining the code and providing support, despite the fact that we could make a lot more money working for minimum wage at Starbucks. Doing so often requires saying no to features.

The final sentence of my reply above is an invitation to people whose cost/benefit analysis of this feature differs from mine to spend their time implementing it. I pointed out some of the factors that need to be considered, as a starting point.