In the guide Getting Started in KiCad p. 47 - par. 23 I read “Click on the Add Zones icon on the right toolbar. We are going to trace a rectangle around the board, so click where you want one of the corners to be. In the dialogue that appears, set Pad in Zone to Thermal relief and Zone edges orient to H,V and click OK.”
Sadly, this is the dialog that appears
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I figure that filling in this area means that the etching fluid doesn’t have to remove all this copper (time and money), however this is only on the top. In this PCB there is a single track on the underside
You select the bottom layer from the layer manager on the right side of the screen and then draw it as you did on the top layer. You always work with the board face up (layer 1 up).
And that single trace on the bottom could easily go on the top layer.
In your dialog screenshot you can see the Layer selection. You already have a track on your bottom layer so you apparently know how to use layers in other situations. There’s never need to flip your board view (although it’s possible in the nightly builds) to put something in the bottom side.
If may save fluid (someone how knows better can answer that), but that’s not usually the reason it’s used. Rather you use copper fills for power planes for electrical reasons. What you did is probably OK in this case. The bottom side should of course be the ground plane, which is the most important.
Drawing zones is just like drawing traces. You draw them on one layer at a time.
If you want a filled zone on both sides, you have to draw 2 filled zones.
Zones are drawn on the “currently selected layer”, just like traces.
(I think you made the wrong assumption that a single zone can be drawn on all layers here).
When drawing zones you can make the zone bigger than the PCB (“edge cuts”) You can set a clearance for the zone to keep of the edges of the boards. If you do this the zone will follow the rounded corners of the PCB.
But more importantly:
You seem to have a small uC on your board, with no capactiors whatsoever.
This is very, very bad.
Any uC (or other digital, and most analog stuff too) needs decoupling capacitors.
Put a ceramic (HF capable) capacitor near the power suppy pins of your uC.
100nF is often used, the value is not very critical.
It is also wise to add a “bulk” capacitor next to the decoupling capacitor.
A 10uF to 100uF Electrolytic is often sufficient.
You also have no voltage regulator on your board. Long (and thin) wires may drop a volt or more when delivering some current. You can compensate for this by using a higher supply voltage and a local voltage regulator on the board.
Have you considered putting in some mounting holes, or is your PCB mounted through the banana plugs?
For experimental PCB’s I often put a few empty connectors in the schematic and add the footprints to the PCB. That way you create an experimentation area, just like on vero board. This makes it a lot easier to make small changes to your PCB if you disover some error, or want to add a small thing (2nd led, transistor, whatever) later.
Have you thought about adding a reset button or a connector for reprogramming your uC?
Even if you draw the connector on the schematic & PCB you are not required to mount the connector, but it will make it a lot easier to solder in the connector if you need to reprogram your uC.
When you talk about Ferric Chloriede I assume you want to etch the board yourself.
This design can easily be made on a single sided PCB.
I’m new to Kicad myself, just started with the copper pour a few days ago so I noticed your top copper plane is connected to VCC. Probably not what you were thinking.
In your first screenshot (Copper Zone Properties) you see VCC is highlighted. This means the copper pour will be connected to VCC. You probably wanted to have it connected to ground So you would have to highlight the “GND” entry in “NET”.
Regarding balancing copper area on the top and bottom. Production houses seem to prefer to have relatively balanced copper (top and bottom). It makes the etching process more controllable especially if there are thin traces.
Regarding removal of copper. Chemistry was my worst subject but I know the ferric chloride is converted to another solution (aka used up) as it etches copper. There is an alternate for the home “etcher” it can be googled but I don’t recall the solution type. I do recall it was somewhat self propagating.
Others have already answered in words, but here are the screenshots. You want to select the bottom copper layer (B.Cu) in the drop-down menu on the toolbar:
This PCB is my effort at the example given in Getting started in Kicad. I will probably etch the board eventually - just to prove to myself I can do it. Then I might go on and do something useful. This assembly will never be completed.
I have never encountered a situation where it was unacceptable to run a trace under an IC package. (Assuming, of course, that the trace satisfied the requirements for minimum width and spacing.) However, in some organizations the “house rules” prohibit routing traces under common passive components in leadless packages (e.g., resistors and capacitors in 0805, 0603, and similar packages). The justification is that the trace, with its covering of soldermask, is thick enough to lift the body of the component off the board, create a “teeter-totter” effect, and reduce soldering yield.
My next step, according to Getting started in KiCad is to create a Ground Plane which will be connected to all GND points. There are only two GND points (U1/78 and LED/1) in this circuit
No, a ground plane is probably not necessary for your circuit. Even circuits where a ground plane is not essential for proper operation may benefit from a ground plane, and almost any circuit which incorporates a “clock” signal (which includes ALL microcontroller circuits) will have better EMI performance if it includes an effective ground plane.
Keep in mind that you are working through a tutorial exercise. Like any textbook, the examples are often contrived to support the lesson. The goal of this exercise is to demonstrate how some tasks common to circuit board design can be performed in KiCAD. The tutorial does not pretend to teach either circuit theory or product design.
If possible, I would like to include a ‘logo’ on my board. I have had a look at stuff from Google and have got as far as creating a kicad_mod file which I think will do the job. At present, that file is in my project folder. Question is, what are the steps to get the logo.kicad_mod inserted into the kicad-pcb image?
There’s no difference.
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