How to start on first small PCB design

Question

I am an electrical engineering student, and I am looking at creating a small PCB with a flashed microchip and a Bluetooth 4 module, as well as a Hall effect sensor for a flow measurement device I want to build.

I have built it with an ESP32 chip, and I want to look at using a flashed microchip and a custom PCB. I can get custom PCBs relatively easily through my university. I am mostly wondering where I should start looking to know how to design this, as it is my first time designing something with a flashed microchip.

Thanks in advance for your help, I am mostly just looking for pointers on where to start, as my Google-fu isn't working for me. I can scroll through parts on Digikey, but I am not really sure what I should look for.

Answer 1

There are multiple stepping-stones here:

First you need to commit to a microcontroller brand. You will need a programmer and software. (the software is mostly free, programmers are not). Your uni probably has programmers, so depending on their equipment this selection may have been made for you. (unless you want to purchase your own programmer)

Once you have selected a brand I would look for evaluation boards. For example the AVR Xplained boards are excellent, but all the brands have the equivalent type of boards. Your uni probably has a bunch of those as well, if not most brands will send some to your uni for free. (Under the motto: Get the students hooked, and they are likely to select our brand when they go into their professional career.)

As well as beeing great for getting to learn the required programming tools (that I belive will be the trickiest part of this project), these evaluation board are also a solid reference for your own board. The layout, components and general infrastructure can be copied from these boards.

Then on to the design itself: Here you have (in my opinion) two options: Your uni probably has some sort of student edition of a mayor CAD brand where it's ether free or at a huge discount. Or: you can use Kicad. That is open source, free and quite good. There are many other CAD softwares as well, but I don't really see any reason to delve into these niche lowcost/free softwares. Kicad has a massive and active userbase and tons of user-made content and tutorials. In my opinon that fact alone makes kicad the ideal CAD to get into when designing your first PCB.

Designing the board is partly learning the CAD and partly learning the electronics. As you have a functional circuit with the ESP, and more than likely will have a evaluation board with a functioning microcontroller your task is to "melt" these two concepts on to the same board. Absolutely possible, even with very little experience.

Answer 2

You'll first need to choose a PCB design software. There are many out there such as Eagle, Altium, orcad, gEDA, ExpressPCB and so on. Many are free, many you have to pay for, some may only work for a certain operating system, and some may work for all operating systems.

I think KiCAD is a good choice for beginners and pros. It is cross-platform, relatively easy to use and has a good range of different tools. You may not be able to fully use it at first glance but there are plenty of Youtube videos and guides on how to use it. For me I found just the docs were the best way to learn it. Also EasyEDA is known to be very easy to use. It is web based. I have not looked at it in much detail but it does seem quite good.

Once you are confident in using the program, you can start designing your board. Make sure to double-check everything on your board when you are finished so hopefully it works first go. After that, you can export your files and send the to your university. were the can make your board. Good luck!

Answer 3

IMHO one good entry point is to learn how a PCB is actually manufactured. That way you learn the concept about the different layers in a PCB and some constraints of what can be done and what not. Manufacturers often have an info section with videos about that, e.g. this one:

https://www.eurocircuits.com/electronic-manufacturing-technology/

https://www.wedirekt.com/en/web/printed-circuit-boards-company/the-online-shop-for-printed-circuit-boards-from-wurth-elektronik/printed-circuit-boards-production.fs-260454.html

Then you could decide for a tool. Back at my university we used Eagle. They have free non-commercial licences with some limitations on PCB size, and since yours is apparently small it shouldn't limit your project. KiCAD seems interesting too but I have never used it. KiCAD is used in the industry as well.

Once you go for a tool, you will find tutorials on how to firstly create the schematics with components from libraries, then export that to a PCB layout, and connect the footprints accordingly.

In a third step, you'll learn about the design rules (like routing high-speed lines etc), but I would not dive too deep into those in the beginning.