Designing custom PCB for production - Page 1
Forum section: electronics / general

author: bisket
author_rank: Newbie
timestamp: August 21, 2024, 02:05:58 am
content: I have a programming background and have an idea I'd like to test out but I have zero knowledge in electrical engineering/PCB designs.I'm hoping to create a custom PCB which has the following components/features in the most compact form as possible:Microcontroller3-Axis SensorTemperature & Humidity SensorBluetooth Low EnergyLIPO BatteryWireless ChargingI've been testing few things using Arduino Nano 33 BLE sense but looking to build a custom PCB for production but not sure where to start. Hoping to get some guidance.Is this something I can learn and do myself in a short timeframe (1-3 months). If so, can you recommend me some resources I can look into?OR would it be better to hire a professional? If so, is there a place where I can find a reliable professional and how much time/cost would this job be?Apologies in advance if any of this is silly question. I lack a lot in this field, hence this post for guidance.Thank you!

author: Kean
author_rank: Unknown
timestamp: August 21, 2024, 02:45:46 am
content: Generally (in my experience) the major effort is in the software development and testing, but it sounds like you have that under control.The schematic is probably not too difficult. There are plenty of similar designs you can review from parts vendors, and probably something with nearly the exact same components. Before copying too much from a published design, check the licensing of it. IANAL, but if you redraw it in a slightly different style you are fine (similar to other artwork).The next thing is defining the final product form and size, as that determines the actual PCB size and shape. This will only be a goal, especially if you are new to PCB design and you won't have a feel for part placement and high tight to can pack them. You need to do this excercise whether you attempt the design, or contract it out. If you are thinking of doing the assembly yourself, then don't try make it too small. If you will outsource the assembly, find someone local or talk to a company like Macrofab to see what they think about your design before you go too far.Start looking at some videos for KiCad, and see if you can follow along. Also read the datasheets of each component with attention to their implementation recommendation, and find general PCB design tips. There is a good PCB design doc written by our host here (Dave Jones), but you'll need to search for it as his personal site is offline (alternatezone.com). Again you should be able to find a bunch of similar published PCB designs, either reference designs for the parts, or open source ones. Maybe even in KiCad format (or a format it can import), and you can view and play with the tools to see if it is something you feel comfortable spending days or weeks using...A good idea is to do a larger initial PCB layout using the same schematic with similar but more spaced out layout for debugging, with plenty of testpoints included. At this stage, I'd often include footprints for possible alternative components or extra parts I think I might want to try.If this is a product you think you might want to commercialize, consider using a pre-certified Bluetooth module as it will save you a heap of trouble later on with certification. I use ones from u-blox. And regarding the microcontroller, be aware that you can often run your application code on the Bluetooth module. Arduino Nano 33 uses a u-blox module with both WiFi and BLE, but also adds a separate microcontroller for the application code - and this make firmware update procedure way more complex. And the NINA module with WiFi is maybe overkill for your needs. Using a single nRF52 style module simplifies this a lot, and the software development is nicely documented by Nordic and others (e.g. Zephyr).There is both Jobs and Work Wanted areas on this forum, so take a look at the posts and replies there, and maybe post your own topic in the Jobs section.Just some thoughts from someone who has been doing this for way too long...

author: Kim Christensen
author_rank: Super Contributor
timestamp: August 21, 2024, 03:27:25 am
content: Quote from: bisket on August 21, 2024, 02:05:58 amHire a professional. It's too big a task to complete in such a short timeframe if you're starting with zero knowledge.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: August 21, 2024, 03:50:58 am
content: Agreed that the software time and effort usually dwarfs the hardware time and effort, so if you have that under control, it helps a lot.Your asks are reasonable (with one exception) but your timeline is not. I don't think you can get to where you want to be within 3 months. If that is a hard deadline, you need to stop and replan. But if you have some more time, I think it's definitely possible. (Unfortunately, I can't say quite how long without knowing you a little better!)You also need to define your end goal a little better, especially if you intend to bid this job out. Do you want a design package you can send out to get a few bench prototypes to prove the design? The same, but in the final form factor? Do you want the hardware design to be fully smoke tested and shaken down, as in preparation for a production run? Or do you want all of the above and more: a full production design file package, fully tested, cost-optimized, and ready for handoff to a contract manufacturer? These each have different times and costs associated.As for size: do not say "as small as possible". Things can always be smaller! How much are you willing to pay? (OK, maybe I'm just salty from hearing "but why isn't itsmaller" too much....) Define an endpoint ("this size is good enough") or a constraint in time and cost, or if you're dealing with a professional, maybe invoke the 80/20 rule.The unreasonable ask is wireless charging. USB charging is easy and fast and cheap. USB-C PD is... well, not, but it's not too bad. Wireless charging is the devil's own creation, sent to torture electrical engineers and ensure their continued sacrifices to the gods of Hell. We can do it... but you won't like the price. Sometimes your idea won't work without it, in which case I'm sorry. For both of us. In other cases... please try to do without. Especially on the first version.

author: Kean
author_rank: Unknown
timestamp: August 21, 2024, 05:50:47 am
content: Quote from: Kim Christensen on August 21, 2024, 03:27:25 amWhile I don't disagree (as a embedded systems consultant), I've see smart software guys pick up the basics of PCB design and digital schematics quite quickly. Things like RF and analog take a fair bit more time of course. As I mention, there is a massive amount of online (free or paid) training for electronics, PCB design, and KiCad, and heaps of reference designs.It will depend on the person and how keen they are to learn. Either way, it is a really good exercise to learn the process and understand the steps we are discussing before contracting a job out.Quote from: exmadscientist on August 21, 2024, 03:50:58 amOh, I missed the wireless charging. Agreed! I've managed to avoid that in all my designs.There are eval kits to get started (e.g. from Wurth), but it adds so many complications to the electronic design, physical design, and EMC (shielding).

author: Doctorandus_P
author_rank: Super Contributor
timestamp: August 21, 2024, 11:05:57 am
content: That one to 3 months, is that for the whole project (inclusive software, production, marketing, financing, etc) or is that just for the PCB design (with or without PCB production and/or assembly?)(Disclosure) I am a big KiCad fan myself. About 10 years ago, when I moved to Linux, I was in need of another (and more modern) PCB design program, and evaluated nearly all available options. When I evaluated KiCad, I designed my first PCB (a blinky) with it in a single afternoon, hand in hand with the (then) excellent "Getting started in KiCad" guide. KiCad was quite clunky back then (Library management was so buggy it did not even work), but I saw it's potential. And now 10 years later KiCad has grown enormously and has already become a quite good PCB design program, and development is still progressing at a quite considerable rate. It is one of the most healthy open source projects I know. It's got a good and active user base (forum answers get answered promptly and correctly) It's got lots of developers (20+ regular contributors) and the KiCad services corporation both does commercial support for companies and guides the project with some leadership (often lacking in Open Source projects).If you want to get started in KiCad quickly and efficiently, then maybe paying for a course is worth it. There are several, for example from contextual electronics, or from Udemy. But I never did that myself.If you want to start with KiCad (or any PCB design software) by self study, then my recommendation is:1. Have a look at "getting started" manuals.2. Combine it a bit with youtube video's and other sources.3. Make at least 3 simple projects, from schematic entry to the final PCB design. About 10 to 20 symbols is the ideal complexity tradeoff. Smaller projects do not train muscle memory, bigger projects get tedious to correct errors. Do not order these PCB's. This takes a lot of the stress out of the learning process and lets you focus on how the software works.When you are ready for your first real PCB:1. Make it a 4-layer if design speed is an issue. 4-layers PCB's are a bit more expensive, but they are a lot easier do design properly.2. Use a full GND plane on an internal layer. Don't think about it, just do it. The whole layer for GND. (Single via's may punch through, but avoid rows of vias that break the GND plane.)3. Use wide tracks for power. Approx 1mm is usually plenty for digital circuits. (High current stuff needs special rules).4. Use thin tracks and clearance for all small signals. 0.25mm tracks with 0.25mm clearance is a good compromise. Any PCB manufacturer can easily and reliably manufacture it. A 0.25mm track can already handle 700mA of current (but with some voltage drop) When your knowledge grows you can refine this later.5. Use a 100nF decoupling capacitor close to each set of power pins on each IC.6. Add project name / date, logo's and mounting holes.7. Pay attention to every off-board connection, especially for commercial products. Ferrite beads or pi filters for digital lines, an inductor or choke as extra filtering for the power input.8. Consider extra ESD protection for all signals that go though connectors.If you simply follow those rules, you are well on the way to design a pretty good first PCB.Everybody orders PCB by sending Gerber files (or IPC-2581 (Stupid name))) to some website. The Chinese are the cheapest, but shipping takes several days up to a few weeks. Ordering locally is faster but more expensive. There are 24 hour services for prototypes, but those are more expensive still.If you want to outsource PCB assembly, the Chinese can do it at an amazing low cost, especially if you stay within their "standard parts". Outsourcing PCB assembly locally gets expensive very quickly, as it requires manual labor to set up the machine. Especially for small orders the cost per PCB are considerable.If you want to solder the PCB's yourself. Don't go smaller then 0603 for capacitors and resistors. Don't go too small with the pitch of parts, (0.65mm pitch is still relatively easy). Buy a decent stereo microscope. I'll assume you already have soldering equipment and material. If you don't have any soldering skills, then outsourcing the production is probably better if you want to get it done quickly.

author: thm_w
author_rank: Super Contributor
timestamp: August 21, 2024, 08:36:43 pm
content: 1-3 months is not realistic at all.

author: twospoons
author_rank: Frequent Contributor
timestamp: August 21, 2024, 08:55:30 pm
content: sensors + RF + wireless charging + compact. For production -> you want to sell it -> standards compliance. Sorry, this is not a job for a hardware design newbie, unless you are ready go through a lot of revisions and have deep pockets - or have an experienced EE mentor.

author: themadhippy
author_rank: Super Contributor
timestamp: August 21, 2024, 09:46:02 pm
content: Quotethink you've just reinvented the microbit

author: nctnico
author_rank: Super Contributor
timestamp: August 24, 2024, 12:20:14 am
content: Quote from: Kim Christensen on August 21, 2024, 03:27:25 amAgreed. Especially if this product needs to pass FCC (and maybe CE) certification, a professional designer who also has knowledge about how to design a product so it has a chance to pass certification, is needed.

author: ArdWar
author_rank: Frequent Contributor
timestamp: August 24, 2024, 12:45:32 am
content: These feature stets are non trivial even for seasoned engineers.For such short timeframe you may even need to consider using ready made (and certified) modules instead.

author: Smokey
author_rank: Super Contributor
timestamp: August 24, 2024, 01:11:00 am
content: Dude didn't say what "production" means. That could be 3 units for himself or 10000 pieces. Big difference in how you approach the project based on the answer to what "production" means. If it's a product that also involves some sort of case/housing which is a separate mechanical design but needs to be done at the same time as the circuit board so it all fits.If it's 3 units for himself (or a small quantity for in-house use), then ya, go for it. Start hacking.If it's 10000 and needs compliance testing, then like everyone said that's quite a project for "zero knowledge in electrical engineering/PCB designs".

author: Sagar
author_rank: Contributor
timestamp: August 24, 2024, 06:59:16 am
content: I think if ypu are going for production, you may hire some professional PCB designer. I have seen many mnufacturing givng out the same services. Have you tried contacting them, see this manufacturer JLCPCB onehttps://jlcpcb.com/?from=sagarnetworks. Or you may get the designingjob done elsewhere like from Altium, EasyEDA, allegro freelancer and then order PCB from here. It's overall your choice but if the desig is for production and you need in bulk try contacting with professional hardware design engineers.

author: EEVblog
author_rank: Unknown
timestamp: March 06, 2025, 01:29:25 am
content: Quote from: bisket on August 21, 2024, 02:05:58 amI'd be willing to bet there is already an off-the-shelf module that will do (or close to) what you want.Is there any custom physical form factor requirement that would preclude this?Does the Arduino nano 33 have everything you need electrically? If so then maybe you just need a custom daughter board to solder it onto?What "production" qty are you talking about?

author: JPortici
author_rank: Super Contributor
timestamp: March 06, 2025, 09:57:41 am
content: Quote from: EEVblog on March 06, 2025, 01:29:25 amminus the wireless charging, yes.With wireless charging, not so sure (i'd be interested though as it's a board i do not really want to design)

author: EEVblog
author_rank: Unknown
timestamp: March 07, 2025, 03:09:09 am
content: Quote from: JPortici on March 06, 2025, 09:57:41 amShould be trivial to add a wireless charging module.Again, unless there to some custom packaging requirement involved.

author: nctnico
author_rank: Super Contributor
timestamp: March 09, 2025, 06:20:25 pm
content: Hacking (crappy) modules together typically doesn't result in a reliable product. Passing certification will be difficult as several tests (mostly ESD and immunity) are the areas where a product fails in the real world as well. I've seen that happen too often. It is way better to do a custom PCB design where all quality related issues are also under full control. And this isn't really hard to do for an experienced engineer given the functions outlined by the OP.