[1.8] How to have a certain box in a model constantly rotate?

[Geforce]

Hey,

 

I'm trying to add my security camera model from 1.7.10 to 1.8. .java models for blocks are no longer used, so I had to make a .json model for my cameras in 1.8. The model looks fine, but I was wondering, how could I have one specific box (the main camera body, to be exact) in the model rotate? In 1.7.10 with .java models, I could just modify the rotation angles of one of the boxes in my TESR, but it doesn't seem like I can do that now. Would I have to use an ISmartItemModel or something?

 

Here's a video showing the camera from 1.7.10, and how I would like it to rotate:

 

Thanks for reading.