For each tablet, a 42 HP front panel is to be prepared.
Aluminum angle profiles provide some kind of bracket, embracing the tablet.
The USB OTG cable has been mounted. Here still without additional wiring to lower line resistance and to switch the ID signal.
Foam stripes provide for padding.
The tablet embraced between the aluminum profiles.
The USB hub has been attached. The USB OTG cable is accompanied by additional ground, VCC, and ID wires.
The USB OTG cable and the power supply contacts show a terrible line and contact resistance. Hence power will be brought to the tablet and the hub via appropriately rated cables and connectors. The switch on the perfboard switches the ID signal of the tablet's micro A OTG connector between OTG and charging mode.