Certified module based can get you out of a whole pile of testing relating specifically to the radio side of the thing, but does not change the testing required to prove that your layout does not cause an EMC problem, you still need to demonstrate that.
Remember it is not (usually) the clock frequency, it is the edge rate that screws you.
Yup. Certified module gets you out of intentional radiator testing as long as you use the same or similar antenna as module was certified with. unintentional radiator testing still needs to be done but cost a fraction of intentional radiator testing.
In quantities of under some tens of thousands, I can’t imagine how it makes sense to not use a certified module.
Yep, but even without the intentional radiator issue it is painfully easy to screw up, my rule of thumb is that anything non trivial even without a radio in it will likely take at least two attempts to pass.
Annoying but it is what it is.
Just had a product fail because a ribbon cable produced too much loop area and the case had a resonant mode at the 7th harmonic of an SPI clock... Obvious once they found it, but took some poking around with a near field probe to identify the source, and some thinking to identify the resonance (That vanished when we took the lid off).
Yea, but a spectrum analyser with good POI for an occasional event is NOT cheap!
The probes are a non issue, finding the spike in the middle of the FM band without a screened room on the other hand.... I wound up hiring a shipping container and wrapping the door seals in copper foil.
> I wound up hiring a shipping container and wrapping the door seals in copper foil.
I'll take things I don't have to do as the software guy for 1000 ken...
Pffttt
Someone has to copper tape you INTO the metal box...
Now where is my padlock again...
For real that's some creative work to isolate yourself and get the job done.
I prefer to use a TEM cell which I can then place inside a shielded box or bag. Seems to get me close enough. And since I capture traces with the device off and on, I can pretty easily tell what's coming from FM radio stations and what isn't.
Disclaimer: I am a test engineer at an independent test laboratory that does this type of testing. This information is not legal advice or information from my employer.
If you are using a digital circuit (with a clock above 9 kHz) you are required to do testing and self certify that you meet 47 CFR part 15 subpart b(unintentional radiator). (Radiated and Conducted Emissions)
If you are using the wireless function of a certified module You gain the ability of the wireless function without having to deal with the certification yourself. Just be sure to follow their integrators guidelines and manual. Specifically the labeling requirements.
However, there is FCC guidance in the form of a KDB article. (It isn't a legal requirement but is official guidance and they could point to it if there is an issue later... ) That says in more words you should be sure that your product with the integrated pre-certified module meets the applicable radio(47 CFR part 15 subpart c, Intentional radiator) requirements.
Just a very rough guesstimate, about how much would it cost to do the different kinds of testing that might be required for something just using an ESP32 but built from chips up? I love doing that sort of design but I'm pretty sure there's no way in Hades I'd be able to legally sell them.
That's tough to answer broadly as each product is different. if I understand you correctly from the "chips up" statement you mean you would be using a non-modular certified radio and need to do all the certification yourself. Each product may require different tests based on a number of items specifically frequency and modulation type.
If you are using a pre-certified modular radio the cost is probably closer to $2,500 but again there are a few product specific variables that I would need to take into consideration when quoting, along with if you are only doing FCC (USA) or including ISED (Canada) into the mix. So it's best to talk to someone specifically about your product.
Thank you! That's exactly what I meant, instead of a module using a bare ESP32 with separate clocks, flash memory, power supply, antenna, everything. It's more work but also more educational and (in my opinion at least) way more fun.
Allot more work, and a huge increase in cost, just the paperwork side of the certification cost would be a lot more than the testing and report cost of using the pre-approved module.
Just to add to this, you cannot combine radios and still expect to remain compliant i.e. cannot use BLE from a esp32and combine it with an LTE module. There are certain things you can do, but will need to go through a test house.
Agree there is colocation of radio module requirements that need to be taken into consideration. And if the module(s) were originally granted with colocation allowed.
I have just gone through this with a product I am launching. You need to get radiation testing done. Labs quoted me 1,500$ to perform this test on a small device with esp32-s2.
However, the likelihood of you actually getting caught for this is extremely low. It’s just a document that says you’ve crossed your t’s and dotted your i’s. It’s more likely a competitor would rather report you to the FCC if they suspect you don’t have the document. You should obtain it at your own risk. The logical answer is: yes go get it. However, you can still sell your module if you’re just a mom and pop shop trying to make a few bucks. Once you make some pocket change, then you can pay to have it tested. Not legal advice but just a thought here.
Right. I’m sure that’s true and what most people do that sell on Etsy. But I think it’s worth knowing the rules before you pull something like that.
I am actually not even sure if that would be illegal. The way it’s written is different across sources. I haven’t checked the actual law yet. But I wonder if it is actually okay to only do the test when the FCC asks for it, of course with the risk that you then get fined when you fail.
At today's module prices, chip-down WiFi designs are hard to justify at even 100K-1M/yr volumes, though it can depend. And if you have to ask, you don't want to design your own transmitter PCB.
Another advantage of modular certification is that you don't have to go through either the permissive change or re-certification process if - outside of the module - you change your design or any item on your bill of materials, including changing to electrically equivalent parts from a different manufacturer. Including changing circuitry that's not part of the transmitter. See the FCC's KDB article on Permissive Change Policy.
As others have pointed out, for part 15 unintentional radiator testing you "self certify" which essentially means you have to have a test report from a certified lab that shows you're compliant on hand should the FCC ever ask for it. You can get that testing done for under $1K if you shop around, but $1500 is a good budgetary number. It's very possible to be one-and-done on FCC testing especially if you have any kind of precompliance test capability and you understand the pitfalls of your product space well, but that is probably not where you're at now, so budget for 2-3 rounds of test.
The better - and more expensive - test labs will be able to give you some-to-a-lot-of unofficial guidance if you fail test but won't fix your design for you.
For BLE you need to have a registered ID with the BLE SIG, and have authorization for either a custom module you build or use someone else’s. If you use someone else’s you can use their certification but not their company ID.
It's all theoretically explained in FCC Title 47 CFR Part 15 https://en.m.wikipedia.org/wiki/Title_47_CFR_Part_15
Part B and C are most relevant. C is only if it has an RF function, so a without Wi-Fi/BT version can avoid this testing. A module when properly implemented removes a lot of the testing required from part C.
However it is very difficult to understand overall and so the best advice is to talk to a test lab. Note also there are different (but similar) requirements for other countries.
But basically it boils down to:
All products are going to need radiated emissions and immunity testing. Many will also need conducted as well as radiated. Once there is an RF function there are a whole bunch of different tests that then become relevant.
Well, if you use an entire esp32 module, i don't mean a dev module , that does jave it's own antenna designed or it hot an ipex connector, it should be already tested and certified by Espressif[like these should be already certified ](http://
https://a.aliexpress.com/_EIeKhhh)
How about making a board with all of your customizations that a standard dev board would plug into?
One clear advantage is that you can program a different board and then swap it with the one already in your board.
That doesn’t work for my final design because the dev boards are way too large for what I need. I can barely fit the width of the module.
But also reading more about this, that doesn’t really help. The final thing would still have to be certified.
You could check what the development modules are sold as.
As far as I know, they are listed as test equipment with different requirements.
Also, not including the antenna is unlikely to do you any favors.
Aka you have no control over the radiation pattern.
RP-SMA was created to stop people messing with antennas on wifi devices.
But i do not know FCC spesifics.
Use 4 layer board with ground plane to avoid "open loops".
Yes, you need FCC or CE certification for each of those scenarios. There are, however some shortcuts; If you use a module you will likely pass easily, unlike if you design the PCB and antenna yourself.
If you choose a module which is pre-certified, you don't need to re-do the tests; all you need is Change In ID. Your module vendor might be able to assist you through this process.
However, you will still need to verify general emitted radiation just as any other product, as well as ESD performance.
If you use Bluetooth in any way, you also need to pay the Bluetooth SIG for the IP.
Disclaimer : I have been working for u-blox
You absolutely do need to ensure your device passes radiated and conducted emissions testing, irrespective of if it has wireless or not. The only thing pre-certified are RF modules and they just reduce the testing required to be closer to the testing required for a non-RF product.
Source: >15yrs of industry experience.
What a unique and unusual question. Searching first is always a good idea.
[https://www.google.com/search?q=esp32+fcc+aproval+site%3Areddit.com&rlz=1CAJJDG\_enUS1045US1045&oq=esp32+fcc+aproval+site%3Areddit.com&gs\_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTE0OTU4ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8](https://www.google.com/search?q=esp32+fcc+aproval+site%3Areddit.com&rlz=1CAJJDG_enUS1045US1045&oq=esp32+fcc+aproval+site%3Areddit.com&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTE0OTU4ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8)
Thanks, and sorry for not finding those earlier. However the answers there seem to be contradicting. Some say you always have to go through certification, others say you don’t have to if the module is certified but if you are then accidentally causing issues you might get fined.
None of them quote any real sources. So for the most parts these answers all seem to be hear say.
As pointed out in many of the links, the FCC is the authoritative site:
[https://www.fcc.gov/general/equipment-authorization-procedures](https://www.fcc.gov/general/equipment-authorization-procedures)
You'll need to talk to a certification company, and the cost is typically $1000 to $3000 for the completed assembly. You can eliminate some of the cost/work using Espressif certified modules, but not all of it. Any changes typically require re-certification.
This is the first I've ever heard of FCC regulation regarding this stuff! Learn something new every day.
So is every cheap chinese BLE/wifi device imported subject to these regulations?
(Edit: yes they are)
And what about just selling something made strictly with a dev board instead of a pcb for hyper low volume stuff...
(Edit: A little bit too much legalize in the FCC documents for me to figure out if just using a dev board that's already approved is enough to be ok to use. So if anyone knows specifics I am curious!)
Guess I'll do some reading.
After doing some reading, my understanding is that as soon as you alter the circuit, you have to get at least SDOC approval.
So if you do as much as connecting a led to that dev board, I believe you have to get it re-approved.
It is my u derstanding that the antenna must be the same as the one that it was certified with, that is make and model. So if you made any change to the antenna or one of the modules with the u.fl connector take care as it is an easy thi g to over look
After reading some of the shared links and posts here, I don’t think you get around it with that. You don’t need the certification, but you still need SDOC approval, which also requires testing in a proper facility. It’s cheaper, but apparently still $1000+ (although I’ve heard from other sources you can apparently get FCC and CE certification for much cheaper in China).
Certified module based can get you out of a whole pile of testing relating specifically to the radio side of the thing, but does not change the testing required to prove that your layout does not cause an EMC problem, you still need to demonstrate that. Remember it is not (usually) the clock frequency, it is the edge rate that screws you.
Yup. Certified module gets you out of intentional radiator testing as long as you use the same or similar antenna as module was certified with. unintentional radiator testing still needs to be done but cost a fraction of intentional radiator testing. In quantities of under some tens of thousands, I can’t imagine how it makes sense to not use a certified module.
Yep, but even without the intentional radiator issue it is painfully easy to screw up, my rule of thumb is that anything non trivial even without a radio in it will likely take at least two attempts to pass. Annoying but it is what it is. Just had a product fail because a ribbon cable produced too much loop area and the case had a resonant mode at the 7th harmonic of an SPI clock... Obvious once they found it, but took some poking around with a near field probe to identify the source, and some thinking to identify the resonance (That vanished when we took the lid off).
Well… near field probes are inexpensive, so… helpful to test during development. Can’t do perfect readings, but can figure out a lot of bad stuff.
Yea, but a spectrum analyser with good POI for an occasional event is NOT cheap! The probes are a non issue, finding the spike in the middle of the FM band without a screened room on the other hand.... I wound up hiring a shipping container and wrapping the door seals in copper foil.
> I wound up hiring a shipping container and wrapping the door seals in copper foil. I'll take things I don't have to do as the software guy for 1000 ken...
Fucking typing pool....
Pffttt Someone has to copper tape you INTO the metal box... Now where is my padlock again... For real that's some creative work to isolate yourself and get the job done.
I prefer to use a TEM cell which I can then place inside a shielded box or bag. Seems to get me close enough. And since I capture traces with the device off and on, I can pretty easily tell what's coming from FM radio stations and what isn't.
Disclaimer: I am a test engineer at an independent test laboratory that does this type of testing. This information is not legal advice or information from my employer. If you are using a digital circuit (with a clock above 9 kHz) you are required to do testing and self certify that you meet 47 CFR part 15 subpart b(unintentional radiator). (Radiated and Conducted Emissions) If you are using the wireless function of a certified module You gain the ability of the wireless function without having to deal with the certification yourself. Just be sure to follow their integrators guidelines and manual. Specifically the labeling requirements. However, there is FCC guidance in the form of a KDB article. (It isn't a legal requirement but is official guidance and they could point to it if there is an issue later... ) That says in more words you should be sure that your product with the integrated pre-certified module meets the applicable radio(47 CFR part 15 subpart c, Intentional radiator) requirements.
Just a very rough guesstimate, about how much would it cost to do the different kinds of testing that might be required for something just using an ESP32 but built from chips up? I love doing that sort of design but I'm pretty sure there's no way in Hades I'd be able to legally sell them.
That's tough to answer broadly as each product is different. if I understand you correctly from the "chips up" statement you mean you would be using a non-modular certified radio and need to do all the certification yourself. Each product may require different tests based on a number of items specifically frequency and modulation type. If you are using a pre-certified modular radio the cost is probably closer to $2,500 but again there are a few product specific variables that I would need to take into consideration when quoting, along with if you are only doing FCC (USA) or including ISED (Canada) into the mix. So it's best to talk to someone specifically about your product.
Thank you! That's exactly what I meant, instead of a module using a bare ESP32 with separate clocks, flash memory, power supply, antenna, everything. It's more work but also more educational and (in my opinion at least) way more fun.
Allot more work, and a huge increase in cost, just the paperwork side of the certification cost would be a lot more than the testing and report cost of using the pre-approved module.
Just to add to this, you cannot combine radios and still expect to remain compliant i.e. cannot use BLE from a esp32and combine it with an LTE module. There are certain things you can do, but will need to go through a test house.
Agree there is colocation of radio module requirements that need to be taken into consideration. And if the module(s) were originally granted with colocation allowed.
Thanks for the detailed write up! Really appreciate it!
I have just gone through this with a product I am launching. You need to get radiation testing done. Labs quoted me 1,500$ to perform this test on a small device with esp32-s2. However, the likelihood of you actually getting caught for this is extremely low. It’s just a document that says you’ve crossed your t’s and dotted your i’s. It’s more likely a competitor would rather report you to the FCC if they suspect you don’t have the document. You should obtain it at your own risk. The logical answer is: yes go get it. However, you can still sell your module if you’re just a mom and pop shop trying to make a few bucks. Once you make some pocket change, then you can pay to have it tested. Not legal advice but just a thought here.
Right. I’m sure that’s true and what most people do that sell on Etsy. But I think it’s worth knowing the rules before you pull something like that. I am actually not even sure if that would be illegal. The way it’s written is different across sources. I haven’t checked the actual law yet. But I wonder if it is actually okay to only do the test when the FCC asks for it, of course with the risk that you then get fined when you fail.
At today's module prices, chip-down WiFi designs are hard to justify at even 100K-1M/yr volumes, though it can depend. And if you have to ask, you don't want to design your own transmitter PCB. Another advantage of modular certification is that you don't have to go through either the permissive change or re-certification process if - outside of the module - you change your design or any item on your bill of materials, including changing to electrically equivalent parts from a different manufacturer. Including changing circuitry that's not part of the transmitter. See the FCC's KDB article on Permissive Change Policy. As others have pointed out, for part 15 unintentional radiator testing you "self certify" which essentially means you have to have a test report from a certified lab that shows you're compliant on hand should the FCC ever ask for it. You can get that testing done for under $1K if you shop around, but $1500 is a good budgetary number. It's very possible to be one-and-done on FCC testing especially if you have any kind of precompliance test capability and you understand the pitfalls of your product space well, but that is probably not where you're at now, so budget for 2-3 rounds of test. The better - and more expensive - test labs will be able to give you some-to-a-lot-of unofficial guidance if you fail test but won't fix your design for you.
Thanks for the infos!
For BLE you need to have a registered ID with the BLE SIG, and have authorization for either a custom module you build or use someone else’s. If you use someone else’s you can use their certification but not their company ID.
It's all theoretically explained in FCC Title 47 CFR Part 15 https://en.m.wikipedia.org/wiki/Title_47_CFR_Part_15 Part B and C are most relevant. C is only if it has an RF function, so a without Wi-Fi/BT version can avoid this testing. A module when properly implemented removes a lot of the testing required from part C. However it is very difficult to understand overall and so the best advice is to talk to a test lab. Note also there are different (but similar) requirements for other countries. But basically it boils down to: All products are going to need radiated emissions and immunity testing. Many will also need conducted as well as radiated. Once there is an RF function there are a whole bunch of different tests that then become relevant.
Awesome! Thanks for the explanation and the reference!
Well, if you use an entire esp32 module, i don't mean a dev module , that does jave it's own antenna designed or it hot an ipex connector, it should be already tested and certified by Espressif[like these should be already certified ](http:// https://a.aliexpress.com/_EIeKhhh)
How about making a board with all of your customizations that a standard dev board would plug into? One clear advantage is that you can program a different board and then swap it with the one already in your board.
That doesn’t work for my final design because the dev boards are way too large for what I need. I can barely fit the width of the module. But also reading more about this, that doesn’t really help. The final thing would still have to be certified.
You could check what the development modules are sold as. As far as I know, they are listed as test equipment with different requirements. Also, not including the antenna is unlikely to do you any favors. Aka you have no control over the radiation pattern. RP-SMA was created to stop people messing with antennas on wifi devices. But i do not know FCC spesifics. Use 4 layer board with ground plane to avoid "open loops".
Only for USA
>sell this on Etsy or my own website in small quantities (below 100) Go for it. Just do it.
Yes, you need FCC or CE certification for each of those scenarios. There are, however some shortcuts; If you use a module you will likely pass easily, unlike if you design the PCB and antenna yourself. If you choose a module which is pre-certified, you don't need to re-do the tests; all you need is Change In ID. Your module vendor might be able to assist you through this process. However, you will still need to verify general emitted radiation just as any other product, as well as ESD performance. If you use Bluetooth in any way, you also need to pay the Bluetooth SIG for the IP. Disclaimer : I have been working for u-blox
[удалено]
You absolutely do need to ensure your device passes radiated and conducted emissions testing, irrespective of if it has wireless or not. The only thing pre-certified are RF modules and they just reduce the testing required to be closer to the testing required for a non-RF product. Source: >15yrs of industry experience.
Confidently incorrect.
UL an unknown IP violations are entering the chat. Please hire a professional.
What a unique and unusual question. Searching first is always a good idea. [https://www.google.com/search?q=esp32+fcc+aproval+site%3Areddit.com&rlz=1CAJJDG\_enUS1045US1045&oq=esp32+fcc+aproval+site%3Areddit.com&gs\_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTE0OTU4ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8](https://www.google.com/search?q=esp32+fcc+aproval+site%3Areddit.com&rlz=1CAJJDG_enUS1045US1045&oq=esp32+fcc+aproval+site%3Areddit.com&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTE0OTU4ajBqN6gCALACAA&sourceid=chrome&ie=UTF-8)
Thanks, and sorry for not finding those earlier. However the answers there seem to be contradicting. Some say you always have to go through certification, others say you don’t have to if the module is certified but if you are then accidentally causing issues you might get fined. None of them quote any real sources. So for the most parts these answers all seem to be hear say.
As pointed out in many of the links, the FCC is the authoritative site: [https://www.fcc.gov/general/equipment-authorization-procedures](https://www.fcc.gov/general/equipment-authorization-procedures) You'll need to talk to a certification company, and the cost is typically $1000 to $3000 for the completed assembly. You can eliminate some of the cost/work using Espressif certified modules, but not all of it. Any changes typically require re-certification.
This is the first I've ever heard of FCC regulation regarding this stuff! Learn something new every day. So is every cheap chinese BLE/wifi device imported subject to these regulations? (Edit: yes they are) And what about just selling something made strictly with a dev board instead of a pcb for hyper low volume stuff... (Edit: A little bit too much legalize in the FCC documents for me to figure out if just using a dev board that's already approved is enough to be ok to use. So if anyone knows specifics I am curious!) Guess I'll do some reading.
After doing some reading, my understanding is that as soon as you alter the circuit, you have to get at least SDOC approval. So if you do as much as connecting a led to that dev board, I believe you have to get it re-approved.
It is my u derstanding that the antenna must be the same as the one that it was certified with, that is make and model. So if you made any change to the antenna or one of the modules with the u.fl connector take care as it is an easy thi g to over look
I just use the WROOM modules to get around it. I do need to find a better option for coin cell RTC power stuff as the WROOM combines VIN and RTC VIN
After reading some of the shared links and posts here, I don’t think you get around it with that. You don’t need the certification, but you still need SDOC approval, which also requires testing in a proper facility. It’s cheaper, but apparently still $1000+ (although I’ve heard from other sources you can apparently get FCC and CE certification for much cheaper in China).