TFW someone says my custom keyboard is probably illegal:
But in all seriousness, this is a particularly interesting discussion
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It is not so much the seller that has to do the certification. Unless the seller is also the maker or importer maybe.
Usually a reseller or distributor does not bother with that, apart from requesting the certification from the maker.
A certification usually involves some back and forth as some parts of the design may have to be changed (if possible on the spot to avoid needing a new session, with all the associated costs and delays…).
It is possible to design from the get-go as to minimise risks of failing the test. Though that require some knowledge and/or experience.
It is also possible to pre-certify, even by yourself in a basic electronic lab. You need a few special probes (some even DIY them) and some sort of signal analyser. And a knowledge of what to look for and how to look for it. That can easily catch the bigger stuffs (and I would estimate for a typical keyboard that would be enough, but you never know how these EMI traps can surprise you :-D).
4 layers, while not actually a panacea in this respect (there will still be some part of the routing where you will not be able to follow the recommendations), is at least a massive improvement over 2. And to benefit from a very small spacing between pair of layers, that’s only possible starting from 4 layers (or unless you consider a 0.4mm 2 layers board, but that gets super fragile, especially if it is part of a kit).
Its price is getting closer and closer to 2. Even at very low volume prototyping (5-10), nowadays you can find it at hobbyist-level affordable. And as PCB manufacturing is priced in good part by surface, with large ones for keyboards you would not need a lot of them to start getting the really interesting prices.
If I was to push the price down, I would try to see how feasible it would be to handle unattended emissions with just drive strength limiting itself, and keep it 2 layers.
But at the same time I would also get some quotes for 4 layers to see if that’s even worth the bother :-D.
For small scale GB, the community could come up with a set of guidelines, and a few OSH examples that have been properly reviewed (i.e. at least pre-certified by a set of competent people). And stay “illegal” and not do the certification. If you can limit the reasons for them to come after you, you are much less likely to have any issue with them ^^.
There are not that many challenges to address in a keyboard: matrix scan, LEDs, USB (well documented), split connection, maybe some I2C (also well documented).
The keyboards of today are already very unlikely to disturb radio emissions or airplane traffic. At worst, a few perturbation with other gadgets on your desk. Something I already witnessed actually, as a USB cable with a jenky connector (bad shielding I think, maybe bad ground connection as well) was going under the TRRS cable of my split and that created errors in the USB communication and the device kept re-enumerating… These EMI issues are real, people X-D.
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Who is going to come and check your keyboard at home? I think the whole discussion is pointless.
You’re right that the FCC doesn’t care that you’ve bought illegal keyboards, but as the hobby grows they will start caring about the people selling thousands of illegal keyboards. If you’re only looking from an end user perspective the only effect it will have on you is the possibility of vendors not selling custom kits anymore (or, at least, a significant pause in sales while they work out how to become compliant). The point of the discussion is to figure out what exactly needs to happen with the vendors and designers in order for that transition to be smoother.
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If they stop selling kits, we can get the parts separately, can’t we? None of the parts emit radio waves on their own.
I don’t think mechanical keyboards can make huge profits for a big corporation to lobby for such law to be passed.
Drugs have been illegal for long time, and are still being sold.
Yeah, that’s one of the potential solutions people have been discussing. As far as I can tell (and I’m not an expert nor have I really been paying a lot of attention here) finding a loophole in the rules is quite a bit more complicated than just selling the PCB separately from the case. Hopefully someone with a bit more knowledge here can clarify.
Either way, here’s to hoping the FCC keeps ignoring us for the foreseeable future 
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Not a ham, nor a radio person, but I wonder if sniffing around with a SDR (software defined radio) could elucidate if there are actually interfering frequencies being emitted. I recognize that it’s not the same as getting FCC/UL certs, but it would certainly be interesting to see what the RF environment around us is like.
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Excellent post. When designing my custom PCBs I have always included large ground planes for this reason.
I don’t think this would really be enforceable unless the keyboard community offends the government somehow.
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just want to add a fun thought I had the other day and discussed with some people… lets say you put all components like MCU and usb port onto a daugtherboard, everything BUT the diodes and the traces to the switches. you connect the daughterboard to the main pcb that holds the switches and the diodes for each switch are routed to another daughterboard (probably a pcb slot because its a lot of traces).
here’s the question: this way the only part that had to be certified, if even, would be the daughterboard and the long but very narrow pcb that holds all the diodes and the PCB itself that holds the switches would not have to be certified because it essentially is just a complex antenna, correct?
so… if that is correct, technically, one would only have to certify a sample of the diode pcb as a one or more diodes of same component on the otherwise empty pcb and the never changing daughterboard. the main pcb holding only traces, a jst connector, and a pcb slot would just be an antenna.
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As said @Pylon earlier the correct process is to certify the whole assembly (PCBs, case and plate), so unfortunately this trick would not work 
Certification is always for a complete device, including any cables, power bricks, etc. that are normally used with it. The fact that individual components of the device have certification has no bearing on the certification of the whole thing, from the lawyer’s point of view. Of course, in practice, if you use already certified parts it is less likely you will have some horrible problem in there. But you still have to certify a complete device.
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Anyone know if it would be legal to replace the keycaps of a keyboard that passed the test? I’m planning to get a prebuilt keyboard (might get an RK61) then adding some keycaps from GMK to the keyboard.
I got a bit confused on the wording of the part about kits, so I’m not sure if replacing the keycaps would be ok.
Additionally, how would pc building fit in this? It seems pretty similar to making custom keyboards, but I guess theres a difference maybe, which allows it to be legal?
That actually sounds worse because the switch pcb would be an antenna that would be spewing noise as the matrix toggles
For keycaps - I would figure you’re probably ok, as DIY modifications may fall under the DIY exemption.
For PC building - it appears you can get either the whole system authorized by the FCC, or have all the individual components (motherboard, CPU, RAM, etc.) authorized separately. If you’re building a PC, most likely all of the components have already been approved by their respective manufacturers - you often see FCC logos on motherboards and graphics cards. So there is no need for the end user to get FCC approval.
https://apps.fcc.gov/kdb/GetAttachment.html?id=vcigJ2hBt%2BPRXEHRt46ZHQ%3D%3D&desc=657217%20D01%20Personal%20Computer%20v03&tracking_number=33230
Just wanted to point out that a missing CE logo permits electronic devices to be imported to the EU and and be sold within the EU but it is not illegal to own or use them. It’s more about product safety. But you basically cannot sue a manufacturer if their products without CE logo wreck up your place due to a fire or chemical reactions with it’s surrounding (ruining your desk and so on).
But also if you buy a product w/o this logo you are not automatically entitled to get a same value replacement from a reseller since it isn’t a “manufacturing flaw” per se.
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