I had develop a small board using some transistors and a microcontroler.
i could do it rightly as i would in altium, then i could start the pcb window and sync the schematics there once i was able to assign footprints.
i am using it on Fedora 34 KDE / wayland.
Now, i have two questions i need to resolve?
First, i need to find out how to i set the size of the real board. I tried drawing a 10cm * 5cm polygon but i don’t know how to send it behind components and traces.
I plan to build my board using a laser printed transfer sheet and single sided copper board since is nothing more than a small experiment.
The other one, i need to know if Kicad is able to auto route for me or if i do need to export the project into an external autorouter.
In KiCad you draw the circumferene of the PCB with lines and arc segments on the “Edge.Cuts” layer:
This works well for simple PCB’s.
If you have a complicated PCB outline, it’s better to draw it with some external CAD program, export it as a .DXF file and then import it in KiCad (Pcbnew / File / Import / Import Graphics).
There is no autorouter in KiCad. The “Interactive Router” in KiCad can shove a bunch of tracks and via’s aside (without loosing connectivity) to make more room for more tracks.
KiCad can export & import Specctra session files, and some use this with “FreeRouter”, but that is another project, apparently has some shady licensing issue’s and also has not gotten much maintenance in the last several years.
Being a power and analog design engineer I have never used an autorouter. Also (including on this forum) I have never heard of favorable results using an autorouter. Is there anyone reading this who thinks that they are useful?
You draw the shape of PCB on the Edge_Cuts layer. That is the PCB.
The shape tools/objects can be drawn on the Edge_Cuts layer (select the layer first).
Also, if items are drawn on other layers, you can either double-click them and change the layer and/or edit the PCB file in any text editor and replace the current layer with Edge_Cuts layer.
Thus, draw the PCB shape and put your parts into it (or, draw it around the parts…
To get a print-out of the shape, use the PLOT tool and set desired layers (certainly select the Edge Cuts layer)…
I think autorouters are useful for high density logic designs. The design service we used to use would talk about some of the more complex designs. Oh… the autorouters aren’t start, walk away and comeback to a finished board. There is usually a few challenging traces. At that time they were using Mentor.
For power supplies, analog designs and those with strict EMC requirement all get placed by hand.
I don’t think so. Logic designs tend to be also high speed nowadays. Meaning it’s a high frequency system. This requires careful routing to prevent EMC problems and to make sure the design actually works.
In my opinion, the software is here to point out mistakes we are making along the way, so humans can figure out a sane solution for these problems. Humans are not capable of checking hundreds of design rules simultaneously, and computers are not capable of understanding the PCB that the human is trying to make.
I think there are two groups of people who think autorouters are awesome:
-The people who make autorouters.
-The people who sell autorouters.
No, As I mentioned our boards were mostly analog and power. All traces were carefully hand routed for maximum function and EMC hardness.
I was only recounting conversations I had with a PCB design service who would use an autorouter for high complexity boards as a starting point to manual trace manipulation. This wasn’t a current conversation, could have been maybe 10+ years ago. Since then I have no knowledge of current workings.
My strategy for creating a board is as follows: I figure out where the connectors should be. then I spend a lot of time shifting, rotating and pinswapping the components around, until the air wires are logical.
Then I route the components (including routing GND traces for critical sections), and finally create a groundplane on each layer, and sprinkle in a generous amount of ground via’s.
I am yet to see the first autorouter that does this.
(btw, agreed on the 3rd category of people that think autorouters are awesome.)
Autorouters CAN be useful, but they are NOT the be-all and end-all to PCB design.
They’re good for helping one visualize areas that may make trace layout challenging (and which calls for a correction in parts layout - THE most important step before commencing actual trace layout).
They’re also useful for suggesting areas that would make good ‘alleys’ through which the traces may be run (again, helping to visualize potential roadblocks that may require adjustment first).
A GOOD parts layout is FAR more conducive to good PC board design than an autorouter could ever be, IMHO.
Yes! I have seen beginners arranging discrete components on a sort of a grid.
Anyway it looks like I have helped to start an interesting conversation.
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Unrelated: I am in Olympia WA where we are forecast to reach 42 degrees C today. This would break our all time temperature record which was set (I think) yesterday. We do not have air conditioning. I am sitting in front of a fan and drinking cold tea. This place is not usually so hot in summer. We can go for years (perhaps 1000 or more consecutive days) during which the low temperature of every morning (including June, July, August) dips below 16 degrees C. Today the morning low at our house was 21 degrees C. Note that our weather reports and outdoor thermometers are in Fahrenheit and I have converted to Celsius for the international audience.
Yep. I’ve seen a board with 3 switching power supply’s fail the EMC certification because the PCB designer placed the component neatly in a grid, instead of placing it in 3 very small clumps of components, minimizing the loop area’s.
We use decimals for Fahrenheit temperatures too. The difference is in the zero point and slope, not in format. The use of the freezing and boiling points of fresh water are as arbitrary as those Fahrenheit used (0°F is the freezing point of salt water, and 100°F was intended to be the normal human body temperature).
If you ask me, the Celsius scale is too compressed for normal human use. Celsius thermostats have to handle half-degree steps because a 1°C is too much of a change.
The first thing to understand is that the climate here is different from that in (Eastern USA and probably most of Europe.) In summer the humidity tends to be low and a daily temperature change (morning to evening) can exceed 22 degrees C. So we typically open windows in the evening to cool the house and close them in the morning. Yesterday when our outdoor thermometer indicated about 39 degrees C (cooler than the official reports) the temperature in this room was probably around 29 degrees C. So the fan helped a lot.
Yes I have wondered about very hot and dry temperature. My brother was in a car in very hot temperature in Israel without working A/C. Hard to believe but apparently they kept windows closed. I would think that sweat evaporation would favor airflow to keep cool but maybe not.
