I took a printmaking course at a local art school (MCAD) a long time ago and it was so much fun! Some of the others in the class were printmakers who had signed up for the course just so they'd have access to bigger machines than they had in their shops. It was really cool watching them work.

I'll have to investigate LEGOpress.

In my case? Two days I think (it was long ago). Two very eye-opening days.

Interlocks are especially interesting when they have to be integrated with software.

For safety, you want the interlock to be performed in hardware (what if SW crashed?) but at the same time, the software should be informed that the interlock is active. e.g., the operator opens the door while the machine is moving. A hardware switch should stop the motion, and the software controller must be told that the door is open and take appropriate action.

The fun part comes in when the interlock is implemented as a hardware switch that turns off power to everything (this is the easiest way to do it!) except the main CPU and then at the last minute, when software is close to completion, inform the software team that "oh, by the way, you have to respond to this interlock triggering at any time during operation and recover gracefully." So now, the first indication that the operator opened the door is that the subsystem you were talking to over a communication link is no longer responding. Is it a comms error? Did the subsystem crash or reset? Or did the user open the door and the interlock powered off the subsystem? Who knows? Just Do the Right Thing.

I loved my 1987 Toyota 4x4 pickup with all its mods. My wife used to say that I'd get rid of her before I got rid of it (wife's still here; I sold the truck long ago).

But no way in hell would I want to be a real accident in one. That's why they're no longer sold in the US. Amazing off-roader, cheap and extremely reliable.

But they're stuck in 1980's crash survivability while the rest of the world moved on.

Hard to believe that it was that long ago!