I am trying to keep the controller box as water-tight as possible. Although I don’t expect it to be hosed down, I can see that with an inherently liquid-based enterprise it is entirely foreseeable that it’s likely to get the odd splash. At the moment the LCD module simply pokes through a hole in the box, so it needs some sort of cover to seal it all up (as well as provide some knock protection).
All I really want is a rectangle of thin clear plastic. So I went looking for some trash that could be repurposed. My first attempt was using an old CD cover. This proved too flimsy – once the edges were removed it was quite floppy. In the end I used the plastic from a box of ex-Christmas Ferrero Roche. I’m sure that an old iPod/iPhone box would work even better (not that I have many of them lying around).
The best way to work the material is to rough cut the sides off to leave a single flat sheet of plastic. A hacksaw or Dremel cutting wheel works well for this. To actually cut the final edges of the rectangle (ie the fine work) the best approach is one similar to glass cutting. Score your line a few times with a craft knife and straight-edge. The bend to snap along the score line with some flat-nosed pliers.
This way the rough stock can be made properly square (as in, given proper 90 degree corners) and the results are quite accurate, straight sides. Any jagged edges can be knocked back to smooth with a light sanding.
Then all is needed are a few holes for mounting screws and (later) a little silicone sealant.
As you can see in the photo above, my box has a little dot imperfection where the injection molding has taken place. I may end up sourcing a better piece of stock and remake using this one as a template. If that were to happen this would actually be a very quick operation to duplicate the two (this one took about 5 minutes to make). Or I may just live with what I have…