Well, as I’ve designed a door to hold all the electronics of this project I need to make sure it will open, I want the box on the back of the door to fit as snugly as possible into the inner box. This will look neat and also reduce the stroke length of the solenoid if I can get them to fit closely with no risk of intersection as the door opens and shuts. To help with this I have produced a scale 2D drawing to work out the radius of the swing of the door, this should give me the correct distance to allow the door to open and shut comfortably within the inner case:

From my drawing I can make out the I need a gap of at lease 6.5mm for the door to clear, I’ve used 7mm just in case (hey I may be accurate but there’s no point in going overboard ).

So I’ve now got the dimensions of the inner case, the outer case and the door, time to start construction…