Add front pcb autorouting

[ohmtech-rdi]

Overview

Autoroute the front PCB to save time.

For now, the front PCB exposes pads with name, and the user needs to air wire all pads with the name name. We made just a tad simpler by having planes for both GND and 3V3, which reduces the number of things to solder.

The freerouting project is the defacto autorouteur for KiCad 5, since the included autorouteur was removed from KiCad 4.

Fortunately, the freerouting autorouteur:

• Is probably good enough given our very simple need,
• Is free, open source, and uses Java, so works on Linux, macOS and Windows,
• Has a command line interface.

Current Status

On branch front-pcb-autorouter.

PAUSED

KiCad 5.1 doesn't include in the python bindings the functions we need. We decided to wait for the release of KiCad 6.0 before continuing on this issue. This release should be quite imminent, has rc1 has been around since some time already.

[ohmtech-rdi]

One major issue we have is that:

• pcbnew.ExportSpecctraDSN and pcbnew.ImportSpecctraSES methods are not available in KiCad 5.1,
• Should they be available in KiCad 5.2 they are unlikely to work from the command line, as they require UI elements to be present (!)

This is the case for KiCad 5.1.9, but also for the latest when this was written, 5.1.12.

One workaround will be to generate the DSN and parse the SES ourselves. They happen to be s-expression files.

This probably some consequent work, while at the same time KiCad 6 is most probably soon to be released. It's probably better to wait until this is available. In the meantime, we could make a short tutorial on how to autoroute using KiCad (ie without automations).

[ohmtech-rdi]

There is the same exact problem with Freerouting which needs UI elements also because logic and views are mixed.

Though on that one, some work has been done.