There's an outside toilet. Functional, and pretty handy because the workshop is outside and it saves traipsing in with muddy boots and up the stairs to the bathroom.
However there's also a plan to knock-through and make access to this toilet from the inside as well, so as to have a downstairs toilet that's accessible without climbing stairs. I don't want to lose access to it from the outside.
This just leaves the problem of how to arrange door locks! How to arrange two doors, so that the dining philsophers can each make access to the igloo when needed. At least one of these doors also needs to be lockable for security, to the same standard as an "outside" door.
Electrickery is one solution: easy to do the control logic, not so simple / cheap or reliable to install the actual locks or strikes.
Any bright ideas?