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Comment by mlsu | Hacker News Reader

Wow, what a coincidence! Thank you for posting, this looks like a great resource.

I am (a very novice, no EE background hobbyist) creating my first design right now.

It seems like there are a lot of design rules that are not common knowledge. And in the electronics tinkering "community" there is basically a vertical wall in the learning curve after Arduino/breadboard. I work on embedded software for a living so I understand that side but some of the electrical stuff really doesn't have an easy learning curve.

I am following along with this video:

https://www.youtube.com/watch?v=aVUqaB0IMh4

and having an OK time so far.

If anyone knows of any other resources I would love to know. And, is there a place, maybe a slack or discord, that would review designs? I really want to have someone look at it before it goes out but I have no clue where I would begin searching for someone to ask.

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The most basic design rules will be provided by your PCB fab so they can vary quite a bit depending on the quality of the manufacturer and the cost you're targeting. Some other design rules (i.e. differential pairs) need to be computed using an engineering calculator using some data from the fab and some choices you have to make. Unless you're pushing the analog-high speed digital boundary you don't need to worry much about them, just choose arbitrary values that result in values within your fab's specs.

However, most other design rules are experimentally derived by the manufacturer of each part. Look for documents called routing or layout guidelines which should be on the same page you find a part's datasheet. The manufacturer of your CPU, RAM, sensors, connectors, PMICs, and so on will usually make them and they'll often include really basic info like how many caps and how far they should be away from some pins, how to route signals to minimize reflections, and so on.

But focus on the two most important words in EE: REFERENCE DESIGNS. Until you're doing mixed signal stuff, you can usually just copy reference designs wholesale and strip out the stuff you don't need. The only hard part is making sure the layers and copper weights compatible. Even professional engineers base their work on manufacturer reference designs when they can.

I don't know the full depth of the trade space of stackup parameters. I go with what the fabs provide. While trying to do some 200 V routing recently I found out something interesting. Higher weight copper layers have thicker prepreg. This is interesting to me because the rule of thumb for 200 V clearance is "0.4 mm in outer layers and 0.2 mm in inner layers". Most prepreg is 0.1 mm, but going to 2 oz copper means 0.22 mm prepreg. This lets me route 200 V without having to worry about arcing through prepreg, specifying a more expensive board material, or going to more layers.

> But focus on the two most important words in EE: REFERENCE DESIGNS.

„I avoid application notes as if they were the plague, because frankly, more than 95% of them are incorrect.“ https://youtu.be/QG0Apol-oj0?si=KTdYlKAlRhGVEDfB

Those are not the same things.

Awesome to hear of new people getting into PCBs! It's wonderful how accessible PCB design has become, and I think KiCad plays a major role in that. If you're the kind of person who can read to learn stuff, I highly recommend this old powerpoint presentation:

https://www.4pcb.com/media/presentation-how-to-build-pcb.pdf

It describes the manufacturing process in pretty good detail. The reason the design rules feel like such a wall is that these design rules are completely based upon the manufacturing processes themselves (thus different manufacturers will have different rules). As you go through that presentation, you'll probably have to search or ask about many of the terms you don't recognize, but that'll just help you learn even more! Next, check out the design rules for a popular fabricator. For example, here's one:

https://docs.oshpark.com/services/two-layer/

And they even include some helpful tips for setting up KiCad to work with their fab capabilities:

https://docs.oshpark.com/design-tools/kicad/

Two other great resources to learn from are Robert Feranec and the Contextual Electronics course: https://www.youtube.com/@RobertFeranec https://contextualelectronics.com/

Have fun!

> and I think KiCad plays a major role in that

I'm not trying to rain on your or KiCad's parade, but what did it for me was EasyEDA's integration with JLCPCB's part library. Combined with JLCPCB's assembly service. For just a bit of extra money I now don't have to worry about footprints, availability, exporting the right files, creating a BOM, etc. I can just order at JLCPCB right from EasyEDA.

I really wanted to use KiCad instead of yet another online tool, but for my first steps this just makes more sense.

Certainly JLC and their EasyEDA integration is a great tool for reducing barriers - absolutely. There are others as well, Eagle for one (maybe even before KiCad got as popular as it is) plus some of the newer tools looks Libre PCB and Horizon. I'm definitely biased towards KiCad, since it's what opened doors for me personally a decade ago.

Congratulations on starting! I am about 14 years in to my PCB design journey and having an absolute blast with it. I am also not formally trained but that hasn't stopped me from continuing to learn and making some pretty complex boards.

The biggest thing I learned lately was, if your board is open source, find some nice person online (twitter, mastodon, reddit, etc) who is willing to offer design review for you. I have learned SO MUCH from having a professional critique my boards.

Also Phil's Lab is excellent! My favorite resource for learning advanced concepts. Just ignore his shilling for Altium and stick with Kicad (which he more recently has been exploring). Kicad is an incredible tool. Learning Altium has value if you want to work at a shop that uses Altium, but Kicad is really an excellent tool that is very accessible.

I do robotics so I do software, mechanical design, welding and fabrication, and PCB design. PCB design is by far my favorite of all these fields!

Here are some checklists from someone knowing his stuff (he seems to be creating GBit networking stuff among other things):

https://github.com/azonenberg/pcb-checklist

I also saw this recommended in the past for assigning functions (like serving as a ground plane) to layers depending on the numnber of layers that your board is going to have:

https://web.archive.org/web/20201112034911/http://www.hottco...

https://web.archive.org/web/20201224132837/http://www.hottco...

...

This is nice, thanks.

One thing I'd add to the schematic checklist is "label every net". It makes setting up net classes much easier and clearly communicates the design in the layout.

Just checked your link - yes, Phil's Lab is good, not aware of anything better for PCB design on YouTube. Maybe some of the Rick Hartley recorded talks he recommends sometimes, or perhaps some old EEVBlog videos would be worthwhile too.

But in general I agree, there's too much fascination with Arduino et al. that I think's mid/long-term harmful to those that stick with it personally.

Rick Hartley's content is fantastic, but I think it caused collateral damage by making hobbyists who work with 8-bit microcontrollers and I2C believe they need to follow the same rules that must be followed for GPUs and PC motherboards. It's not Rick's fault, but it's a matter of the cult-like following he's developed among some hobbyists. Old-timers on PCB design forums try to impress and intimidate novices by citing his advice without really understanding if it's relevant. And most of the time, it isn't.

A lot of his videos should be prefaced by "it's interesting, but you don't need to worry about it unless you're working on the types of projects I'm paid to work on." Without this disclaimer, PCB design becomes less accessible. It's akin to teaching basic chemistry by starting with quantum foundations and insisting that everything must be derived from that.

Yes that's fair enough, I mentioned it in the spirit of what else is good learning material on YouTube, not/forgetting 'creating my first design right now'.

Phil's Lab is pretty good 'zero to DDR' though I think, for PCB at least - you might need some awareness of basic electronics first, he does schematic walkthroughs and projects too, but it'd probably seem pretty quick and unexplained if you're coming to it not knowing some fundamentals.

I can look at it. I'm a hobbyist like you but I have been using KiCad and making PCBs for a few years now.

If you want to be anal you can print the PCB from KiCad on a regular laser printer at actual size and "stuff" your paper PCB with the components you intend to install. I've used a push-pin to poke small holes in the paper PCB and then threaded the resistors, etc. into the holes to get a sort of sanity check that the components are going to actually fit with one another.

The latest KiCad has a 3D viewing mode that seems to have a similar benefit. But I had a few components on my latest PCB that KiCad didn't know about so there was no 3D model for those components. (I could probably hunt for these component's 3D models on the web but I am too lazy.)

Otherwise, I see lots of "can you review my PCB?" on r/PrintedCircuitBoard/ (https://old.reddit.com/r/PrintedCircuitBoard/).

Here's another YouTube video I've sat through: https://youtu.be/3FGNw28xBr0?si=57iSLz2EFxOdUmXn

I'm interested in the course as well though. I suspect there is a lot I could learn.

Laziness is the enemy. I spend a lot of time on things that some might consider frivolous. I always make sure to set up pin assignments and constraints properly so ERC and DRC checks mean something. I've found that the 3D models are quite helpful in finding pain points in clearance for multi-board assemblies, large components, and user interactive components. It's also really handy for checking mounting configuration (hole size, standoff height, will standoffs obliterate traces, etc.)

I did spend the time to find 3d models on the web to plug into my 3d views and it was definitely helpful.

Rather than paper, I think you could Kicad-design a 2D grid of holes matching an existing proto board (https://www.amazon.com/ElectroCookie-Solderable-Breadboard-E...) and then do the placement and routing in Kicad, and then finally assemble the board in place. To avoid fritzing.

> It seems like there are a lot of design rules that are not common knowledge.

Even worse, there ard a lot of design rules that are shared as common knowledge, but that are wrong or detrimental to modern designs. Rules that applied when all you had were througholes, slow rise times and no emission tests to worry about.

Modern MCUs for example might just run at 8 or 16MHz if so configured but can have rise times in nanoseconds, so emissions must be considered despite the "slow speed" of the clock.

Another big one is having multiple capacitors one decade apart for decoupling, ie 1uF, 0.1uF and 10nF or something like that. With modern SMD capacitors you'll almost never want to do that. Instead use multiple large ones, ideally in the smallest package you can.

> And, is there a place, maybe a slack or discord, that would review designs?

I've had a good time over at MicroType Engineering's discord[1], got a separate room for design feedback. Also has a YouTube with some helpful videos[2].

[1]: https://discord.gg/CwWUxqdr

[2]: https://www.youtube.com/@MicroTypeEngineering

> Another big one is having multiple capacitors one decade apart for decoupling, ie 1uF, 0.1uF and 10nF or something like that. With modern SMD capacitors you'll almost never want to do that. Instead use multiple large ones, ideally in the smallest package you can.

To expand (search for "antiresonance"): https://www.mouser.com/pdfDocs/c39e.pdf

Great post! I’m an ex maths/physics person and have always been into EE and electronics as a hobby. I’m currently working on a pcb and am also struggling to find that leap in knowledge.

I have recently found the eevblog forums [#] which are extremely valuable. I haven’t posted there yet but am planning on engaging and seeing if I can learn some deeper knowledge.

I’m struggling to pick which MCU to use exactly. Let alone what brands of rotary encoders are good, or which water proof usbC female port I should use!

[#] https://www.eevblog.com/forum/index.php?PHPSESSID=s3ph2f4cbq...

All the parts from Mouser or Digikey are good. It takes time to find your favorite vendors, parts and most enjoyable datasheets. Part picking process is very time consuming.

Any tips if I wanted to get something pre manufactured through the big pcb players?

How to figure out what parts are in stock, what can be used with each other. Any tips for beginners? I’m looking to get a pcb with parts soldered on (ws2812 LEDs, atmega328 and supporting parts. Is this easy and feasible to do?

I do my assemblies by myself. It’s faster and more convenient during prototyping stage. While the boards alone cost 400€, with assembly it might cost 4000€. First revision has errors and it’s a waste of 4000€ then. I can recommend in Germany Beta LAYOUT GmbH. They do usual boards for good price with good quality. Be aware, that nobody wants waste the time with 1500€ first order with assembly of 5 boards. Maybe you can find some student willing to play with electronics on weekend for cheap. And yeeah, maybe overseas is cheaper. But I don’t do that anymore.

I have not put in an order yet, but I am looking at JLCPCB which seems to have a wide-ish variety (not like mouser or digikey but still, most things available) of parts at reasonable prices. I am designing with their partslist in mind so that they can assemble for me especially the tiny SMT stuff that I have no hope of doing myself.

I think you may need to pay a bit of extra fees if you don't use their "in house" parts but so far it looks reasonable.

>It seems like there are a lot of design rules that are not common knowledge.

Totally. And it can often be unclear how to proceed when the design rules you do know conflict.

Ultimately I've learned over time it's about the process rules, not design rules. Follow the same logic design process each time refining it to be better knowing that the design rules will be bent and even broken at times.

Join the EEVBlog forums and spend some time reading feedback threads on PCB design. You can ask questions about your own as well.

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