SMD circular pad

catcha03 · June 1, 2016, 5:00pm

Hi,

I’m trying to create a touch pad for a project, it has to be a smd circular pad without a copper fill in the middle, basically a thick round trace around the board perimeter. I can’t use a tru hole because i’m placing the components there. Any ideas how to create those?

Thanks!

Aaron

catcha03 · June 1, 2016, 7:37pm

I need some kind of ring trace not a filled pad.

cbernardo · June 2, 2016, 3:52am

At the moment for the stable release the best way to do this is to use a simple SMD pad and use other software to generate the sequence of straight tracks to mimic your circular patch, then cut/paste into the kicad_pcb file. Alternatively, you can have a look at the custom shaped pads patch mentioned here:

Joan_Sparky · June 2, 2016, 1:06pm

You can build the ring outside of KiCAD with this python script and copy&paste the output into your kicad_pcb file and reload the layout.

gist.github.com

https://gist.github.com/JoanTheSpark/b083249af176b9113e99

KiCAD_CopperArc.py

# tested in python 2.7.2
# works for KiCAD 5978 by parsing output of this script into a xyz.kicad_pcb at the right place

import sys, os
import shutil
import math

#              0        1          2      3      4        5    6
LIST_elmt = ["  ("," (start ",") (end ",") "," (layer ",") ","))"]
#LIST_elmt = ["  (gr_line (start 131.571908 182.314571) (end 112.874456 120.68499) (angle 90) (layer Dwgs.User) (width 0.1))"]

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If you connect a net to it via a track deactivate DRC beforehand ( >Preferences>General) and after you connected it activate DRC again. The copper arc/ring track will then ‘join’ the net and KiCAD will remember that.