Most of the parts seem to fit together. I made a silly mistake with one of the dimensions as I do not use the arduino in the CAD and I did not notice one of the assembly issues .

Overall it is pretty compact and I think this is ok for a first prototype. Improving the form factor could be a good project to build upon. This will be atleast partially a job for someone interested in electronics as we might want to move away from using an arduino and breadboard to something more compact.

You will need a drill and drill set for the assembly. Most of the features used to align and fix the pieces are cylindrical in nature to allow you to make the small adjustments with a drill( as opposed to a mill)-this is required when the holes don't print perfectly.

I am also going to have to re-design the IMU mount as I have a new idea to mount it which can result in a smaller device.

I am attaching some pictures which will help explain the assembly ( full instructions will be available only after I reach a somewhat final design. I am posting these updates because some of you may want to suggest improvements on the design). My hands are shown for reference. (I have small hands).

For the modular design of the wand, it will be more than just swapping out buttons or components. I am thinking along the lines of attaching additional frames. So for example, you can take the wand and take a frame for a two handed submachine gun and attach the wand as one of the handles for the gun.(We will now use the orientation data from the wand which is more reliable).

Then because our exoskeleton glove can haptically render squishy features, it can be used to create a virtual trigger(haptic feedback) -(not possible with braking mechanism).

So why do we need to attach that frame? Because when you hold a physical gun, it places constraints on your hands. I.e. Both hands need to be at a fixed distance from each other in physical space. If we do not have a frame to grip with both arms then there will be a mismatch between what you feel and what you see. This is not only bad for immersion but creates real problems for input. Since the gun frame is supposed to be rigid, both palms end up with a fixed orientation with respect to each other. If we do not have the frame, the arms can move with respect to each other. Now how do we take the input? The orientation of only one? That is a one handed gun. It will cause a mismatch. Do we use relative position to calculate the angle? That is somewhat better but position tracking is unreliable. Furthermore, even with position tracking, it is still un-natural. Therefore we need the gun frame.

So why not just create a gun VR device? That might be a good project for someone to work on. I am trying to keep it modular because I want people to be able to take this one device and do lots of things with it. VR is already expensive and it will be nice if we can re-use components as much as possible.