Ideas
First thing to do is to limit movements, by reducing any unnecessary arm movements and finger's micro interactions would be the main interest. The use of touchscreen's smartphone (after iPhone was introduced in 2007) is a great example which has been proven as an intuitive way for human computer interactions.
Current Solutions
A typical physical controller is usually equipped with a set of buttons and a joystick which can be used for manipulating AR/VR elements; however, it is usually bulky and is likely to cause arm and hand fatigue for long time usage. Hand tracking, on the other hand, requires no external hardware making it a more natural experience but it can only be operated within the tracking range of a tracking device such as a camera or short-range radar, and the accuracy may be a problem for micro interaction or in low-light environments. Another problem need to be addressed with hand tracking is the limitation of memorable gestures of hand tracking.
Drafting
To reduce unnecessary arm movements, I proposed a thumb mounted device that sense finger gestures for micro interactions and is based on hand tracking for positioning. But the device alone has not addressed the limitation problem of the hand tracking, so a set of hand interfaces controlled using simple swiping gestures is be added to the presence of the device in XR. The interface's complexity varies depend on the use cases yet the gestures to operate should be simple (swiping oriented).
Ideas about such device and its interfaces have been drafted as showed in the below images.
3 thumb-based approaches were considered, the thumb nail device was chosen.
Hand waving
Hand waving
Another approach, this time is a thum semi ring
Hand interface ideas
Draft specs
Draft specs
Object manipulation
Hand interface with indicator in XR
Hand interface with indicator on the device in XR
Hand presence/appearance in XR and in reality.
Another ring approach
Why thumb?
In terms of design difficulties , a thumb mounted device is more challenging to design say compare to index finger as everyone has his or her own thumb shape. But the benefit of using thumb is the more flexibility joints in comparison with other fingers so that it can be used to freely swipe on one or more fingers or using another finger to swipe on the bottom surface of the thumb, the big size is also a benefit that provide larger interactive area on thumb.
Put Into Action
In order to prove the feasibility of the idea, a proof of concept need to be created, it happened that I have a thesis need to be done so two birds with one stone. The plan was submitted to Dr. Chao Gao, and he helped me with the components.
At this stage, I first encountered with VR via my Oculus Quest 2, which is very important that we focus on this platform later on. Also an 3D printer was acquired, to help with developing the design of the thumb mounted device.