How to make a stone (or something similar) and put there electronics? I'm an electronics hobbyist. I'd like to put a Wi-Fi module in my garden. It would be awesome if it would be possible to put that electronics into a stone or something similar. It doesn't need to be able to open.

Things I considered:

1. There's a rock for hiding keys available on the market:


The seller says that it's made of synthetic resin. But I'm not sure how to make that in home conditions? This specific product is too small. I'd require something a little bit bigger.

2.


  You might just take a watertight hobby box and an adhesive, perhaps like the foam used by pond hobbyists, and 'glue' rocks over the box. – user2448131


IMHO that wouldn't be ideal enough? I mean you could easily see that it's just a bunch of stones that are glued, right? I think I'm looking for something more plain/consistent.

The idea is good in general but this time I'm looking for something that would cover it from every angle. Such a whim.

So, how to make such a thing like the box for hiding a key or something similar easily at home/garage workshop conditions?
What about Feather Rock? That is lightweight and easy to alter. Or check out some of the hidden outdoor speaker ideas and simply convert them for your project.