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Inserting wires or zero-ohm resistors in PCBNew

Asked by Chris Wilkinson

I'm designing a single-layer board as a hobby project. It's about 20 square inches and has about 90 through-hole components. It's probably impossible to do the routing on a single layer, so I'm going to solder some wires in some of the larger nets. Is there a way to insert these into my board in PCBNew? Basically, I want to add pairs of pads to my board and have them be regarded as connected, but without any actual track connecting them.

My temporary solution is to use a 2nd copper layer to draw the wires. Two vias represent the pads, while a trace between them represents the wire itself. There are some problems with this, though: Vias in the ground net become drowned in the ground plane (there's no thermal pad for a via) and the 20-odd traces on the 2nd layer are hard to route because they're all very long and tend to criss-cross a lot. So, while this method works, it's rather messy and I would like to stop using the 2nd layer if possible.

Thanks,
- Chris

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Lorenzo Marcantonio (l-marcantonio) said : 		#1

Your approach is usually the one done for manually-assembled single layer with jumpers (i.e. chinese power supplies :D), and it's substantially correct.
Of course you need to use proper discipline with the 'track' on top layer: autorouting it's not helpful for single layers (AFAIK all of the routers are build for two or more layers), so you need to control yourself and do jumper-like tracks.

The thermal via problem however it's still there. For that you need to design the board as if it was for insertion production with 0-ohm resistors (i.e. using components for jumpers). This has the advantage of marking on the silk where jumpers have to be put and having them on the BOM.
You'll need do define some jumper-module of various length (or simply use the resistor ones) and place them in the schematic where the jumper is needed, so some netlist roundtrip is needed.

With the first method, if jumpers to ground are only a few, during the finishing pass you can add an hole to the ground zone around the via (to avoid swamping) and then connect it manually to another near ground pin.

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