Note: presentation renders are pretty accurate when it comes to dimensions, but some details are still missing.
In terms of mechanical structure QLBRD is composed of three layers, two of them are made of five identical segments:
The innermost part is frame ring already mentioned in previous log:
The middle one is stiff (printed most likely out of PLA filament) set of five modules. They serve as skeletons for outermost layer:
The outermost modules are wraps for ones from previous layer printed in flexible, rubber filament (most likely TPU). Modules (middle and outermost layers) will be printed as one piece with double or triple extruder. I will try both solutions as I recently finished my two extruders printer. Triple extruder can help when it comes to PVA (solvable filament) supports that would enhance precision.
Modules are mounted to the frame ring (for now I prefer screw mounts, but will work on some latches). When mounted contacts of PCBs inside modules will meet contact fields of common power and data lines on the ring. I consider two ways of making these lines, first, easy and fast is to make them out of kapton metallized with copper with etched leads glued onto the ring. Second, that may require some experimenting is to use conductive filament and PLA to form leads directly into plastic. For sure will try this, but cannot yet tell how viable is this solution.
On the cross section below the assembly mentioned is visible. PCB in green. You can see that ends of the module (will call it wings) can bend (flex) outward, but cannot inward (actually current visualization would be hard to bend, due to lack of indentations between module body and wings, I must yet figure out best layout of hinges). This ensures that QLBRD can be slid onto hand like a bracelet, but when held in hand will retain spherical shape. Wings, while rather tiny (approx 20x15x3mm inside) can contain tactile switches, 40mA LiPo batteries, micro USB socket and anything that could fit such space. I also consider leaving some little inward flex capability in some modules and with help of smd microswitches plan to turn certain wings into buttons.
Right, buttons. Some modules (depending on their position, they must fall under fingers or thumb) contain buttons. First version will use simple micro tactile switches. They fit. However I think of using some more sophisticated solution. Thumb can operate either buttons or a 4 way micro switch (joystick). Flexible wraps on such modules can have protrusions indicating their position. You can see how it's going to look on below render (without protrusions).
QLBRD can contain many types of modules, not only logic, bluetooth and buttons. Also displays, gsm and others. Soon (when some modules I ordered arrive) will show their renders (must measure them and see what I can strip, bend, resolder :) ).