i never thought i would touch that black magic called pcb design … but for several art projects i need to make some “breakout boards” with a keyboard switch and 2812 LED’s. It needs to be compact and every switch to be on its own board (i want to do different shapes and maybe one odd switch in the wall or something). I thought for prototyping and experimentation that would be nice. The switches will be read via a mux and the LED’s to be handeld like a ws2812 led strip with FASTled lib, daisychaining the modules.
Did i do it right? I followed the datasheet wireing example. Im not much of an electrical engineer…
It would be nice if someone could take a look at it and tell me if i goofed up
Thank you!
First: Congratulations with your first KiCad project
Using KiCad is not so difficult. Although some people seem to struggle a bit in the beginning. Different people think in (slightly) different ways. I started with KiCad over 10 years ago, and back then I made the first (dummy) project in the first afternoon I started with KiCad. I was evaluating PCB suites at time, and that dummy project convinced me to start using KiCad. I just aborted evaluation at that moment (I had a 3 or 4 other candidates on my shortlist, and KiCad being fully Open Source was another driver to adopt it).
Designing a simple PCB is easy, but don’t overestimate and attempt to design a PC Mobo just yet.
From here onward there is a pretty big list of details to learn. It’s common practice to use RKM code - Wikipedia notation for resistors and capacitors (Farad is with a capital F, but in RKM notation it’s omitted entirely. ) Your capacitors also look quite big. It looks like 1206 size, while 0805 or 0603 is more common.
Keeping all SMT parts on the same side also makes production easier, both DIY and for PnP machines. When a PCB becomes more complex, one of the first things to learn is to why and how to implement a good GND plane. Using net classes, and different track widths is also pretty high on the list.
The more modules you expect to daisychain the bigger probability of problems. Module after module 5V will be lower and lower (resistance of tracks and connections can’t be ignored).
For very long line of modules the better would be to use 12V and locally regulate 5V (at each module, or one for several modules).
Local regulators would be relatively expensive and complex for this.
A better option is to use parallel wires for power, and only daisy chain the data lines for the WS2812 LED’s.
Unless you are dealing with capacitive crosstalk (usually requires relatively high voltages) there is no advantage to using tracks thinner than necessary. I like to make the tracks (as wide or almost as wide) as the pads to which they connect, so long as you have enough pcb area to do that.
The PCB fabricator does not lower their price when you etch more copper away.
Fatter tracks are more mechanically robust. They have less DC resistance and generally have slightly lower inductance, along with slightly reduced inductive crosstalk.
KiCad also have integrated calculator for ‘everything’.
Discussions about track width even if it affects your KiCad use are not related to KiCad in sense that you know what you want but don’t know how to get it from KiCad (this forum tries to concentrate on answering such questions).
