The line you’re interested in:
Spin = 1 # ccw = +1, cw = -1
Spin = 1 is the code, anything behind # (hash) is a comment and usually refers to the code before the hash and will not be interpreted as code
So, to make it spin clock wise you have to set:
Spin = -1 # ccw = +1, cw = -1
How could I design a spiral inductor with increasing track width as shown in the figure?
adjust the radius and track width every segment or turn in the code?
Okay. I see in the code that I can change the track width. I have other things to consider first before designing the inductor. I will ask here again when I start with the inductor.
Thanks a lot 
Hi @Joan_Sparky,
I would like to design a self-resonator that consists of two superimposed copper spirals printed on both sides of a substrate as shown below.
(Yes, I am aware this is a 5 year old thread)
I sort of like the spiki program.
Here a picture of a real-world application.
The product is a mass produced one-time Key generator, so every cent counts.
The screws in the back are used as some kind of electrical interface, probaby for programming the device in the factory.
The inductors on the screw terminals help in preventing ESD damage and such, together with the spark gaps below it. I find it a real beautiful design. Dave probably would have recognized it also if he wasn’t talking all the time and focusing on making his video’s.
Very spiral alike objects can be made out of half circles by cheating.
Example:
Assume you have concentric half circles with odd diameters (1, 3, 5, 7mm) on the left, and with even (2,4,6mm) on the right, then the end match up perfectly by shifting the left set 1/2mm up or downwards.
Having a separate application for Spiki (how does that PyQT stuff work?) seems a bit much. Having such a spiral inductor generator as a Footprint Wizard in KiCad itself seems to be more useful to me.
I’m also pretty green considering Python, and was surprised by:
useNLopt = True
try: # check if nlopt is available
import nlopt
except ImportError:
useNLopt = False
which suggests spiki should compile / run without the inductor estimation stuff…
That concentric circles trick is great! Thanks.
FYI I had to shift the left set up/down 1.0 mm
That being said, the python script from Joan is a great solution if you need more control over your geometry.
Hi together,
came to this problem as well today and found a very pragmatic approach. Since I use Inkscape to create PCB Art from time to time I had the idea to use the spiral tool of inkscape to generate a nice spiral.
H together,
it is nice to learn how to make a spiral, but I’m getting interested in the oval coil shape
who can help me to know what I should modify and how to get it
Great suggestion from Knochi. If you don’t want to use a Python script, this is actually quite practical.
The only limitation is that you can’t go to inner layers from a footprint. I found a workaround : the .dxf file can be imported directly in Pcbnew. The process is actually quite simple
Here you go, you have it in just a few clicks, no text editing at all.
(edit : I’d share a screenshot for convenience, but I haven’t found how to upload it here)
The link to KiCAD_CopperSpiral_v3.py KiCAD_CopperSpiral_v3.py (6.3 KB)
seems to be broken. I do get an XML error. Is there a ‘good’ link to the file?
I scanned the above posts and didn’t notice any comments about the Simple approach (perhaps I just missed it…)
Without using a Plugin:
• Create the Spiral in Inkscape/other, Save as .PNG
• Load the .PNG into Kicad’s Bitmap_To_Component Convertor. Export to User layer (that creates a Footprint (.mod) file
• Place the Footprint into a PCB
-Double-click and Edit the Library Footprint > Change the User layer to a Desired Layer
Screenshot shows the Footprint before and after the layer change edit (now on B_Cu)…
I used your code & run with online compiler. I also added the row
Spin = -1
I get the result as below. Could u please explain it.
" A module you have imported isn’t available at the moment. It will be available soon."
This is the run code:
import sys, os
import shutil
import math
import itertools
from copy import deepcopy
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))“]
#LIST_elmt = [” (segment (start 118.7 106.7) (end 119.4 106.7) (width 0.25) (layer B.Cu) (net 0))"]
DICT_elmt = {“seg” : [“segment”, "(width ", "(net "],
“arc” : [“gr_arc”, "(angle ", "(width "],
“lne” : [“gr_line”, "(angle ", "(width "],
}
DICT_lyr = { “dwg” : “Dwgs.User”,
“cmt” : “Cmts.User”,
“cut” : “Edge.Cuts”,
“fcu” : “F.Cu”,
“bcu” : “B.Cu”,
}
def FNC_string (element,
STR_start, #1
STR_end, #2
Angle, #4
layer, #5
width,
):
STR_line = “”
“”"
0 1 2 3 4 5
LIST_elmt = [" (“,” (start “,”) (end “,”) “,” (layer “,”) (width “,”))“]
“””
for i in range(len(LIST_elmt)):
STR_line += LIST_elmt[i]
if i == 0:
STR_line += DICT_elmt[element][0]
if i == 1:
STR_line += STR_start
if i == 2:
STR_line += STR_end
if i == 3:
if element == “seg”:
STR_line += DICT_elmt[element][1]
STR_angle = “{:.1f}”.format(width)
else:
STR_line += DICT_elmt[element][1]
if element == “lne”:
STR_angle = “90”
else:
STR_angle = str(Angle)
STR_line += STR_angle + “)”
if i == 4:
STR_line += DICT_lyr[layer]
if i == 5:
if element == “seg”:
STR_line += DICT_elmt[element][2]
STR_line += str(Angle)
else:
STR_line += DICT_elmt[element][2]
STR_line += “{:.2f}”.format(width)
STR_line += “\n”
return STR_line
def FNC_polygon (element,
STR_start, #1
STR_end, #2
Angle, #4
layer, #5
width,
):
STR_line = “”
“”"
0 1 2 3 4 5
LIST_elmt = [" (“,” (start “,”) (end “,”) “,” (layer “,”) (width “,”))“]
“””
for i in range(len(LIST_elmt)):
STR_line += LIST_elmt[i]
if i == 0:
STR_line += DICT_elmt[element][0]
if i == 1:
STR_line += STR_start
if i == 2:
STR_line += STR_end
if i == 3:
if element == “seg”:
STR_line += DICT_elmt[element][1]
STR_angle = “{:.1f}”.format(width)
else:
STR_line += DICT_elmt[element][1]
if element == “lne”:
STR_angle = “90”
else:
STR_angle = str(Angle)
STR_line += STR_angle + “)”
if i == 4:
STR_line += DICT_lyr[layer]
if i == 5:
if element == “seg”:
STR_line += DICT_elmt[element][2]
STR_line += str(Angle)
else:
STR_line += DICT_elmt[element][2]
STR_line += “{:.2f}”.format(width)
STR_line += “\n”
return STR_line
def FNC_spiral (cntr, # (x,y)
radius,
sides,
startangle,
tw, # track width
td, # track distance
turns,
layer,
net,
):
STR_data = ""
baseX = cntr[0]
baseY = cntr[1]
segangle = 360 / sides
segradius = td / sides
for i in range(turns * sides):
# central rings for HV and SNS
startX = baseX + (radius + segradius * i) * math.sin(math.radians(segangle*(i) + startangle))
startY = baseY + (radius + segradius * i) * math.cos(math.radians(segangle*(i) + startangle))
endX = baseX + (radius + segradius * (i+1.0)) * math.sin(math.radians(segangle*(i+1.0) + startangle))
endY = baseY + (radius + segradius * (i+1.0)) * math.cos(math.radians(segangle*(i+1.0) + startangle))
STR_data += FNC_string ("seg", #type of line
"{:.6f}".format(startX) + " " + "{:.6f}".format(startY), # start point
"{:.6f}".format(endX) + " " + "{:.6f}".format(endY), # end point
net, # angle or net value
layer, # layer on pcb
tw, # track width
)
return STR_data
if name == ‘main’:
Center = [105.0,105.0] # x/y coordinates of the centre of the pcb sheet
Radius = 1 # start radius in mm
Sides = 24
StartAngle = 0.0 # degrees
TrackWidth = 0.4
TrackDistance = 0.9
Turns = 8
Spin = -1 # ccw = +1,cw = -1
Layer = "fcu"
Net = "1"
print FNC_spiral (Center,
Radius,
Sides,
StartAngle,
TrackWidth,
TrackDistance,
Turns,
Spin,
Layer,
Net,
)
Hello and welcome @D_B
Unfortunately you may have to wait some time for a reply from @Joan_Sparky as that member has not written on this thread for 5 years.
A KiCad Plugin for Drawing PCB Tracks in Spiral Shape
GitHub - tristanitschner/kicad_spiral_plugin: A KiCad Plugin for Drawing PCB Tracks in Spiral Shape
Thank you for the reply. 
