I made this box for a WLED interface, it use a prototype board (veroboard) 5x7 cm.
You can easily mod or improve it, link to Onshape source with parameters is included !

There's 2 variantes in the Onshape document, the first one with 2 pillars and the variante 2 with 4 in corners. 
Both use M3x 8-15mm, need buttons screw  for variante 2

https://cad.onshape.com/documents/2a2bd6058f5a06fdbeb56caf/w/52f0517faaa373a85e9df326/e/9e442f572f08b83dd8202c4e

note: in Onshape document, to use variante 2 you need to suppress both folder on main part:
- BASE Spacer for Screws (supress it for variante 2)
- TOP Pillars (supress it for variante 2)