Connector symbols for example do not have footprints assigned in the lib (we would need over 1000 symbols otherwise)
The same is true for simple devices like resistors, capacitors, …
1 Like
Thank you Piotr.
I am assuming that when I assign a footprint to a component that I am giving it a physical dimension. Two questions come up.
- How do I know what component KiCAD has chosen for this assignment?
- Can I assign a Digikey component footprint so my parts can be placed right onto the board?
I am not up-to-date with it to answer. I was editing a schema only once and 8 months ago.
@Rene_Poschl help!
The footprint does not typically come with a part number. Kicads normal setup is a specialized symbol pointing to a generic footprint (Take the NE555 pointing to an SOIC footprint. That footprint is used by many other symbols.)
For connectors (which is the main part of your pcb) the story is inverted. There the symbol is generic but the connector footprints are specialized for one component. You mentioned molex connectors as your option above. There are many molex connector footprints in the Connector_Molex library. The footprints have the clear text series name and the molex part number in their name.
I was just reading an article on footprints but I think it was from an older version. New version looks intimidating. Into the deep end I go. What time is it where you guys are?
Okay. I have to run for a bit. Be back after supper. 3:30 here. Not sure where everyone else is. Thanks everyone for the help so far. Getting there 
I have decided 2 days ago that I will have two R libraries. In library R the element 1k will be 0603 1k resistor and in library R1 (1 because 0402=1005=1mm length) 1k will be 0402 1k resistor. The same with capaciotrs.
I wend today to work and planned to define libraries R1 and C1 but found this thread and…
I am in Poland = 21:30
OKay. So I am setting my footprints for my connectors and there was mention of using a female connector for the power supply to plug into. Is this the norm or what does everyone think?
you should use it.
1 Like
@bwilliams60 - I think you need to give us an example what digikey component you want for J1B1 ? Then some one will able to help you with how to assign footprint.
Also - I like to point out “again” not importance for now. Is that Reference naming you have may look better with KiCad if you name them JB?, then when run Annotate, KiCad will make them like JB1, JB2… Then it look more natural than J1B1, J2B1, …
Also, Reading the out-dated manual will help you a lot about the concept of how KiCad work - And I would think reduce a lot of question you was asking.
And watch the simple video I point to you is not enough. If you can try make the simple board following that you tube. Once you get it right, then I believe you will much more understand all the process , and work flow, and issue you currently asked. It may took you haft of a day max (event me may not able to do it in 5 mins, but that is not the point)… but will save you and other a lot of time for complete your actual board.
Of course you cannot understand everything or do everything in 5 minutes in the video suggested by nhatkhai 21 hrs. ago. I had to start and stop the video repeatedly while following it, trying to find the controls and the right kicad module (eeschema, pcbnew, footprint editor) to use before I could do any task. Probably took me an hour or two or three. I wasn’t counting.
But BuildElectronicCircuits’ video shows the workflow needed to make a kicad
PCB CAD drawing from a schematic. The tasks shown are:
Draw schematic.
Layout traces on PCB.
Assign footprints both from existing kicad libraries and by making your own
footprints.
Run ERC on schematic.
Set up DR (design rules) so pcbnew will follow them when laying the traces
for your net.
But I did not write these tasks in the necessary order to make the PCB. The video shows the steps in the correct order.
Also, the video does not cover Design Rules.
These tasks are sometimes called a “work flow diagram”. An analogy is
driving to a far-away city to which you have not yet driven. To reach
your first city, you must drive in a certain direction for a certain number
of hours and then when you arrive at the first city, find the route you
need to drive on and in which direction to go to the second city. And so
on and so forth until you reach your destination. Then when it’s time
to go home, your navigator has to reverse all the directions, changing all
the R turns to L turns and all the L turns to R turns so you can retrace
your path in the opposite direction. A “work flow diagram” is similar
to the written list of turns showing where to turn, which way, where, and
how (as in “Turn R at the tee.”) A diagram that you can look at to keep
from getting lost.
And you will get lost the first couple of times. After that, you’ll know
the route by heart and can keep the road map and the written list of turns
in the glove compartment.
However, it isn’t at all important unless your objective is to teach
kicad to your students. Even then, it doesn’t matter. Just give them
the URL to the video, and they will figure it out on their own.
So I made my first PCB of BuildElectronicCircuit’s simple demo. circuit.
The LED illuminates when I connect the 9V battery. It was simply a
way to achieve success quickly, without the possibility of failure.
This is standard operating practice to learning anything complicated,
with many steps and one proper procedure to unite the many tasks into
one long flow of work. You do the demonstration project that your
instructor already knows works.
I should state the purpose of a schematic diagram. A schematic dia-
gram is like a recipe. By following a recipe, you can mix dough,
flour, water, yeast, pumpkin, sugar, and spices together in a way that
they chemically bond together to form a delicious pumpkin pie that you
can eat when it is cool.
A schematic diagram is a recipe for a circuit. A person has already
made the circuit, and has told you it works. The schematic diagram
tells you which parts you need to buy and how to interconnect them,
and to how much voltage and current to apply, and precisely where,
to make a working copy of the circuit.
A device called a breadboard (not the kind you cut bread on) is used
to temporarily connect wires together, using the wires as nets. When
you succeed in connecting all wires exactly where they must be connected
and avoid connecting any wires anywhere else, then your circuit works
when power in the form of voltage is applied to it.
A PCB replicates these wires in its own nets, bound to a fiberglass
board. A net is a wire. A PCB is a set of nets all held together
in one place, with the components shown in the schematic soldered
to the nets… When you find a mistake in your PCB, you will have
to cut a trace here, or run another wire there, until it works correctly.
And then update your kicad model, so that the mistakes won’t have to be
fixed on future copies of the PCB. Just like making corrections to
your pumpkin pie recipe.
Hope this helps…
2 Likes
Russ, thank you for the long and thoughtful explanation of the video. I wasn’t taking a shot at it, I was simply stating that it is not something a newbie should watch and hope that it will go that well for them. I know from being a technician that the first time you do something is all about learning the proper steps, and doing things right. And then you get fast. And then you get good. A good teacher will keep his feet on the ground and not let success go to his head while still remembering where he started. I think many people on forums know there stuff and know it well, but teaching it to somebody is a little different. It has to be fed in parts like building the foundation of a house. And then you add on until that final day when you turn the key to the front door and you know you are home. The video is very good and I am familiar with what schematics are, PCBs, electronics and components etc but design software is a whole new beast and I am fighting the good fight to get it done. Thanks for the input. Much appreciated.
I just went back and watched the video. Things make a lot more sense now that a lot of it has been explained to me (the why). Very good video.
Okay here is where I got to. Any suggestions. This is the way I would this to end up on a rectangular board or similar to this but I am sure there will be some good suggestions on how to make it look better.
1 Like
Sorry, I’m a little late getting back to that. Today was my Day1 build of my new 3D printer.
The following my have already been fixed, but here it is anyway just in case the accidental shorting of signals survived the subsequent edits:
Actually the problem here isn’t so much of an 4-way junction, but when @bwilliams60 placed the 12+_RLY label he accidentally put the label connection point where the two wires cross so he accidentally shorted the CAN_HI with the 12+_RLY signals. I see a similar issue where he accidentally placed the RLY_GND label on crossing wires just under the relay connector shorting two signals that shouldn’t be.
2 Likes
All good. I removed all the labels and went with wire only. Ran ERC and in PCB stage now.
I think, now it is the time to think about the traces that carry large >0.5A current to calculate a minimum Trace Width to avoid it get heat up to much (Temperature Rise)… Using Googling/PCB Calculator from KiCad main menu to…, then start your traces…
This is basically, he did not give himself enough space to work with. So it is hard to tell which net name/label go on which wire. They look very ambiguous, that why I ask him to just forget about label for now…