Files allows to create a wireless button box based on “Zero delay” bluetooth PCB board.
Button box is meant to work with PC ONLY and DIY OSW Steering wheels.

*READ CAREFULLY*
Assebling instructions:
The bottom case is designed to hold a flat “503870” Li-Ion 3.7V battery 1250/1500 mAh (72mm x 38,5mm x 5,3mm) on the central hub-zone by using 2 simple cable ties. Battery should be connected to the "Zero Delay" PCB via 2.54mm JST Male connectors (like any other input).

The “Zero Delay” PCB should be placed right over the battery and fixed using (4x) 3mm wood/plastic screws. 
Left side of the case has a little slot to place a “4056” USB-C Charger. By following the symbols on charger's PCB you can wire it to the battery making a simple circuit that allows to charge the battery and power the PCB up using a simple ON/OFF switch (I drilled the right side of the case and placed one as showed in picture).

Case has also integrated supports for (2x) rotary encoders (which may be removed by widening holes diameter to guarantee some extra space for 2 buttons - 1 per side).
Top is fixed over the case through (5x) M5 flared screws. To place these screws, (5x) M5 Threaded inserts has to be heated and screwed into the corrisponding holes provided on the case. 
Top has holes for (10x) generic momentary button switches and (2x ) 6mm rotary encoders (hard to make them work correctly because PCB only supports switch inputs - I tried. In case replace them with buttons)

A (4x) ø70mm cetral hole pattern is perfect to fit the button box on a generic universal Quick release hub and supports a large variety of Steering wheels (Flat OMP Superquadro-like).
Rear side of the case can be drilled to add holes for Magnetic paddles and switch buttons (I suggest Turn-Racing ones).