I have schematics that contains elements like potentiometers, motors and buttons that are part of schematics but should not be mounted on PCB but connected via connectors.
When I create PCB, KiCAD insists that all components from shematics are placed on PCB. I cannot find way to avoid that. The only way I managed to do is to remove those components from shematics which is ridiculous solution.
Is there better way to do it? Something like marking component not to be mounted on PCB
This is certainly the easiest solution but it is also worth pointing out that there is a side effect which may be important - items marked with a # will not appear in the BOM.
I always use PCB schematic and not device schematic.
So I would not use motor at schematic but its connector (not motor symbol with connector footprint, but connector symbol with connector footprint).
When I send such PCB documentation to be assembled no one will be searching for motor (as it is not in BOM) but for connector (according to BOM).
If the device is so complicated that I need also its schematic the PCB will be there a rectangle with some connectors shown (I suppose, as I never did it).
That is OK for complex stuff, but for simple constructions it is more practical to have all in one schematics, including external components like potentiometers, led, switches or so which are mounted on housing, not on the PCB directly.
Using # works fine. O also like idea to use footprint of connector instead actual component.
I am pretty surprised this can be done only through hacks. It is very common need.
Is it the addition of the # that you consider a āhackā? Why? I would not want to have any electronic component on the schematic which would not get onto the PCB without a clear visual indication and the # does the job quite well, even for example when printed on paper. Itās also simple and fast to use.
If you want to hide the text, you can simply set it to invisible:
But I would not recommend that. It can get pretty confusing once youāve got your PCBās from the fab and wonder why itās missing some componentsā¦
Schematics are also not meant to be ābeautifulā. Their purpose is to convey information to engineers on how a piece of electronics is supposed to work, and what components to put on the PCB.
That said. KiCad has had a long and bumpy history and is continually being significantly improved. Especially in the last handful of years. Itās probably even starting to surpass commercial programs by now. (But I wouldnāt know, because Iām so happy with KiCad (and biased) that I would not use anything else anymore.
KiCad developers also listen to their users. If you consider the # a hack and can think of a better way, please post it here. If itās a good idea more people will agree and your proposal may eventually be integrated into KiCad.
I did not mean to sound negative. I like KiCAD and I also use only that for schematics.
I meant hack as I couldnot find it in documentation. Even after I learnd about it here, i sti was unabel to find reference in documentation.
Other than that it causes other issues, for example component does not show in BOM. I suppose it would also cause issues in simulation.
My conclusion is that # means ignore this component, treat it as meaningless drawing.
Solution with using different footprint also has itās own quirks, someone already mention it.
I expected there is option on component to mark it specificaly that it does not go to PCB requiring no tricks. That would mean it is still part of schematics and goes to BOM. On PCB it will not have usual footprint.
Not exactly. The # means either the symbol is a Power symbol or the symbol will not appear in the netlist and BOM. Well, power symbols never appear in the netlist or the BOM.
I would not go so far. To be honest the # prefix is a legacy hack that will hopefully be gone with the new file format.
Somebody in the past thought it might be a good idea to let the reference do double duty and use the # prefix as a sign that the symbol in question should not appear in the BOM or get a footprint.
I am sure this was mainly intended for power symbols. It has the (possibly unintended) side effect of being useful for off board components or symbols.
I would hope the new file format has at least two separate options for controlling if something should have a footprint and another one for if it should appear in the BOM (both might best be implemented such that they can also be used for PCB assembly version handling.) Just to be clear: I have no knowledge about this. It is just an idea that came up in this context. I do not know how the new file format will look in this regard.
I like idea with different footprint the most. It is logical. Even if component is not on the board it has to be attached, so there should be at least connector or soldering pads.
The only drawback, as someone explained, is that footprint info is printed on board instead of real component info which is confusing. If KiCAD in some next version fixes that I believe it wold be quite good solution.
In my current project, I am going to make PCB by hand so all I cared was to avoid having external components on the board. Both hacks will do the job.
I agree, hermit proposed a correct solution. Also, ā#Referenceā is also a good feature to add additional clarity to schematics, but these āvirtualā components must be explicitly marked as āvirtualā components for printable versions of shematics.
Hi,
I am a rather occasional user of Kicad, for my own needs, not professionally. I use since v4 and like it. Just to add my 2 cents to this discussion. In my view, one should be able to put in the schematics both onboard and offboard components, including the necessary connectors, and marking somehow which are offboard. For example, think of a front panel potentiometer: one puts in the schematic the potentiometer and the connector pair, say 3-pin female onboard and the corresponding male ofboard, as a connected pair, draw wires, etc, and marks potentiometer+male connector to be offboard. In this way all is logically connected, for electrical checks/simulations, etc., all included so as to be in BOM (perhaps those offboard in a separate section), but when designing PCB offboard components are simply ignored. Just a suggestion, no idea how difficult would be implementing it.
Like when you use, say, Word, I guess thereās 2 ways to use Kicad, one is for āhome & hobby useā, the other is more ābusiness useā.
In a business environment, your Word document wiould be correctly formatted, using headers and sub-headers and chapters and sections.
For home use, we just make a bit of text bold if we need a header etc.
Same for Kicad: for business use, you will be using a sheet to represent a single board (it may have child sheets, but they are really just āpart of the sheetā. If you want to have a drawing of the PCB used in a āproductā then youād have a āparentā sheet, that includes the components not on the actual PCB. Thus the circuit diagram 100% matches what you need on the PCB.
For home use, maybe you just need schematic capture, in which case you can do what you like: I was using Kicad this way last week, to document a circuit I built on stripboard. I used wire junctions (= black blob!) to represent a pin, that wires would connect to. Clearly thatās fine for THAT need, but not ok if I wanted to make a PCB from it.
So, I guess you need to decide how you, personally, want to use Kicadā¦ if you are wanting to design PCBs, then you need to be a bit more strict in what you do when you create the circuit diagram.
You can achieve that already with careful use of the # āhackā described above. I have used a pair of generic M & F headers here, which I have place over the relevant wires. The off board components (J1 and VR1) are pre-pended with a ā#ā so wonāt be on the PCB. The downside is that neither J1 or VR1 will appear on the BOM. I think/hope a better solution will be addressed in KiCad V6.
For more complex wiring looms, you might like to look at QElectrotech.
Yes, of course it can be done. What I meant is to have this incorporated as a feature of Kicad and not done as a sort of workaround. letās hope for V6.
Cheers
