According to the Create® 3 robot docs, the robot features two surfaces on which you can attach whatever you need.
Given the fact that both surfaces are accesible from below, the bracket was designed to have as much footprint as the Raspberry Pi itself.
The model was assembled with Heat Threaded Inserts. In case you had never hear of them, here is a very detailed guide from CNC Kitchen.
I am providing the exact measurements of the inserts that the model was designed for:
Longer inserts will not work.
The following list contains all the necessary elements to assembly the bracket.
Hope you find it useful. Cheers!
The author marked this model as their own original creation.