The mechanical interface is derived from the single Eurocard, with DIN 41612 connectors having up to 32*3 connector but shifted the front panel to the side. This creates a front and a back panel that can accommodate connectors. The maximum height of the PCB is 80mm, that is half of the Eurocard (160mm).
Instead of the DIN Connectors angled 4 pin for Grove or 40 pin headers for Raspberry can be used to plug into the motherboard. The Motherboard is optional.
OpenSCAD has been used to design the ElecX. OpenSCAD allows to parameterize the ElecX to have different sizes. ElecX is designed for 3D printing. The OpenSCAD files are available via https://github.com/linurs/elecx
The front bracket contains the user interface, whereas the back bracket holds additional connectors to peripherals attached. The front or back brackets could have optionally its own specialized non standardizes PCBs to be more flexible and avoid cabling. Double (or even more) slot modules are also possible.