Lesson in drawing schematics grinds to halt

[Rene_Poschl]

Same resistor, different footprint:

The vertical version reduces the space needed on the pcb surface. But it does increase the height requirement.

[Rene_Poschl]

@Vagulus

I assume he wanted a screenshot of pcb_new->preferences->library manager

I don’t know where I would find that! I can see a library editor but not a library manager.

open pcb_new. (The tool for making the layout. Third button in the kicad project manager) In it click on the preferences menu. Then click “footprint library manager”

[Vagulus]

[Vagulus]

@Vagulus

I guess I just measure the resistor I am going to use to get ‘L’ and ‘D’ but what is ‘P’?

I am still interested in what ‘P’ stands for.

[Rene_Poschl]

As expected you get the libs directly from github via the github plugin. (See the column “Plugin”)

This means that kicad will download the libs everytime it needs them the first time in a session. (So opening cvpcb after a restart)

This is the reason why opening cvpcb takes quite some time the first time you start it. (The libs are about 100MB. And you download them every time)

[bobc]

P is pitch, distance between pads (which often corresponds to distance between pins, but in the cases of TH resistors the leads can be bent to many forms).

[Rene_Poschl]

The naming convention for footprints is explained as part of the kicad library convention. kicad.org/libraries/klc#f2

Disclaimer: This convention is for the lib intended for the future kicad 5. Kicad 4 footprints have slightly different namings (Example: the v4 lib uses “pitch” in some footprints and “P” in others. In kicad 5 we unified this such that all footprints will use “P”. We also added more information to the footprint names. This mostly affects complex footprints like the ones for BGAs)
Sadly there is no such detailed rule set for kicad 4 (That is one of the reasons why the kicad 4 lib is a bit messy with regards to footprint naming. And also the reason why i linked that rule set.)

For completeness here the library convention that was used for the version 4 lib: https://github.com/KiCad/kicad-library/wiki/Kicad-Library-Convention

And another disclaimer: Not all footprints follow the KLC. Especially not in the version 4 lib.

[Vagulus]

Thanks to Rene and bobc.

[davidsrsb]

@bobc

P is pitch, distance between pads (which often corresponds to distance between pins, but in the cases of TH resistors the leads can be bent to many forms).

Pad/hole centres to be more exact.
Typically a 1/4W resistor might be formed for a 10mm pitch

[SembazuruCDE]

@davidsrsb

Pad/hole centres to be more exact.

Typically a 1/4W resistor might be formed for a 10mm pitch

@Rene_Poschl
The KLC just says pads, but as davidsrsb correctly points out it is more accurately pad centers. (Just saying “pads” can be confused with attempting to define the gap between pad edges which is incorrect.) I advocate to making this minor clarification in the KLC.

[Vagulus]

@Vagulus

I decided to go back to the beginning and start again.

I am working from the start through 'Getting Satrted in KiCad and have reached Par 52 on Page 18. Here I am instructed, ‘For R1 and R2 select the Discret:R1 footprint’. Trouble is, I can’t find any library Discret or Discrete in CvPcb. I used _R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal - I’m not going to etch this thing so the size is really irrelevant.

Is there a Discret or a Discrete libaray?
Is my alternative selection appropriate for an ordinary resistor?

[Vagulus]

An observation on Par 58, Page 19 of Getting Started in KiCad:
This paragraph appears to be written for someone using UNIX or one of its spawn.
Using trusty () Windows 10, I found the required XSL file in
c:\Program Files\KiCad\bin\scripting\lpugins.
When I clicked ‘Generate’ a file called Tutorial1.xml’ was created in the project folder.

As I say - just an observation.

[bobc]

@Vagulus

Is there a Discret or a Discrete libaray?

Is my alternative selection appropriate for an ordinary resistor?

“Discret” is one of the old French named libraries, it no longer exists I think. Your alternative looks fine.

All the new footprints are great, but the paradox is that it makes it more difficult for newbies, or tutorial writers.
I wonder if we should have a library called “tutorial” or “basics”, which has the basic components.

[dchisholm]

@Vagulus

. . . Is there a Discret or a Discrete libaray?

Is my alternative selection appropriate for an ordinary resistor?

Many - probably most - of the library names are different in the most recent versions, compared to when that tutorial was written. If you found a library containing a bunch of footprints suitable for resistors, you’re almost certainly in the right place.

Like the Doctrine of Original Sin recognizes that some of us are more original than others in our sinning, some resistors are more ordinary than others. Going by the footprint’s name it sounds like a suitable footprint for a through-hole 1/8 watt film resistor, or possibly a 1/4 watt (if you bend the leads right at the end of the resistor’s body). I typically put 1/4W thru-hole resistors on 0.4" (10.16mm) pitch.

The “official” answer to your question is probably something like, “Open the footprint in the ‘PCB Library Editor’, and compare dimensions to your part’s Data Sheet.”.

Dale

[Vagulus]

@dchisholm

The “official” answer to your question is probably something like, “Open the footprint in the ‘PCB Library Editor’, and compare dimensions to your part’s Data Sheet.”.

Thanks for that
Yes. That’s roughly what I did.

[Rene_Poschl]

There is also a detailed post in the FAQ on how to use freecad with stepup to really check footprints without the need to do any math.

Tutorial: How to check footprint correctness?

Checking a Footprint Against a Suggested Footprint in the Datasheet Requirements for Following this Tutorial Freecad preferably version 0.17 or newer KiCad Stepup workbench (Can also be installed directly via the addon manager found under Tools->Addon manager) Some way to make a dimensioned drawing Drawing dimensions workbench This workbench is sadly no longer maintained. Tech Draw workbench included in freecad since version 0.17 Export from freecad as dxf (via for example tech draw) and dim…

[Vagulus]

I have just progressed as far as using PcbNew and, to my horror, I encounter a screen with red detail on a black background. There must be few better recipes for eyestrain. Is there any way I can change at least the background colour?

Please, to those of you gallant folks who are creating the new version, please either change the colour scheme to something legible or make the colour scheme editable. Thanks

[Rene_Poschl]

The colors are already editable. For layer colors middle click on the colored square next to the layer names. (In version 4 you only get a small number of colors to pick from. v5 will allow the full 255 values per channel.)

I am not sure if the background color can be changed from within the gui.

[Vagulus]

@Rene_Poschl

I am not sure if the background color can be changed from within the gui

I tried and couldn’t find a way - mind you, I don’t know what all those abbreviations stand for anyway. I couldn’t find anything in the PcbNew manual. Not to worry - it’s not as bad as I thought (not quite) and the footprints and the rats’ nest stand out clearly.

[Vagulus]

A more important problem is defining the edge of the PCB. Getting Started in KiCad, page 24, par. 11t instructs “Now we will defne the edge of the PCB. Select Edge.Cuts from the drop-down menu in the top toolbar.” and the PcbNew Manual confirms this “The outline is drawn as a sequence of line segments. Select Edge.Cuts as the active layer and use the Add graphic line or polygon tool to trace the edge, clicking at the position of each vertex and double-clicking to finish the outline.” Problem is that thete is no ‘Edge’ I can find in the drop-down menu at the top of the window.

Where do I go to find this setting?