7 ms·

Cool - it looks like a well-designed board, although the timing is a bit unfortunate with the ESP32-S2 emerging as an ESP8266 replacement with USB. A few quest

Cool - it looks like a well-designed board, although the timing is a bit unfortunate with the ESP32-S2 emerging as an ESP8266 replacement with USB. A few questions: * Should the relay have some sort of isolation, like an optocoupler? * Is it FCC-certified? * Like other people asked, any information on how the antenna was designed? I like the old-school dome LEDs. And it's cool to see another project with a CH340 USB/USART bridge, even if they wouldn't need it with an ESP32-S2.

pdabbadabba 6y ago
> * Is it FCC-certified? It would certainly appear to lack the FCC ID label/marking it is required to have if it is FCC certified. So probably not. Thus, it also appears doubtful whether it can legally be marketed or sold in the U.S.
- conk 6y ago
  A search for "Malouf" on the FCC registration website provided no matches. Most likely this product is not registered. In addition, this product lacks a CE mark and has no UL/FM/CSA listing. I'm curious what creepage/clearance requirements were factor into the design. This product is potentially dangerous if the relay is switching line voltage.
  - deleted 6y ago
    [deleted]
- simcop2387 6y ago
  IANAL, But I think device as-is can likely be sold and marketed perfectly fine. Test-kit and dev-kit stuff is regulated a bit differently under the assumption that it's not going to be in mass use, and also that it's likely going to be used to develop another product that will get the fcc certification. https://emcfastpass.com/fcc-rules-kits-subassemblies/ https://emcfastpass.com/fcc-rules-kits-subassemblies/
  - pdabbadabba 6y ago
    The link you provided appears to say the opposite about kits: "Based on the definition above, it looks clear that non-authorized kits that are intended to form a complete product when fully constructed are technically not legally permitted to be sold in the US. That is because if you are marketing and selling a kit to an end user, which the user will then build into a full product, there is no reason to suspect that the normal rules would not apply." The subassembly rules could work, if they apply, but I don't see how this product fits the definition of a sub-assembly: "No authorization is required for a peripheral device or a subassembly that is sold to an equipment manufacturer for further fabrication." In fact, I think it's a stretch to say that any of these test-kit, dev equipment, or subassembly rules apply. This basically strikes me as being marketed as a consumer product -- albeit a product for very tech savvy consumers.
    - sokoloff 6y ago
      I don’t believe that dev board is a complete kit by the meaning of that rule. Certainly there is ample precedent for other dev boards (intentional and unintentional radiators) being sold without certification.
      - iancmceachern 6y ago
        Like everything on this site: https://www.tindie.com https://www.tindie.com
- peterburkimsher 6y ago
  This is the exact reason why I didn't see through my plan to build and sell the EspUSB (a very small ESP board that fits inside a USB-A port). I got 3 units built for myself by PCBWay at a cost of $77. I got quotes of ~$500 for 100 units from Elecrow and Makerfabs, but didn't know what to do with the other 90. Although I really want this great little gadget to be easily available, I can't afford $10,000 for FCC certification, and therefore I have no solution. If anybody wants more details, email espusb@gmail.com and we can chat about it on there.
  - iancmceachern 6y ago
    I wonder how the folks that sell on Tindie get around this... https://www.tindie.com/ https://www.tindie.com/
    - tesseract 6y ago
      There are various exemptions for subassemblies and other non-end-user products. Those may not always apply. However, in practice, a product that's sold in small quantities and does not in fact emit egregious electromagnetic interference is unlikely to attract enforcement attention. So a fair bit of skirting of the rules does go on.
      - peterburkimsher 6y ago
        Based on the PAL project and WiFi capability, I think the ESP8266 does emit electromagnetic radiation. Whether it's interference or a feature depends on your perspective.
    - deleted 6y ago
      [deleted]
  - antoniuschan99 6y ago
    What about using a pre-certified module (eg. Wroom-02 or wroom32)
    - 6y ago
conk 6y ago
I don't see any benefit in using an optocoupler. Using a transistor with flyback diode for protection is acceptable. Both the relay and ESP8266 are powered from the same 5V source, adding an optocoupler is not really isolating anything.
- elcritch 6y ago
  Sometimes it’s easier to deal with a combined part than two parts. It can reduce assembly costs for small volumes, or if the person doing the design is just familiar with the opto.
LeifCarrotson 6y ago
Regarding your first point, the relay has 2,000V of coil-to-contact isolation: https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf Though it does look like the clearance/creepage distances on the PCB to the low-voltage ground plane are not any wider than 2mm or so, which is acceptable for 120VAC, but not acceptable for 240VAC per IPC9592. I wouldn't worry about sticking this in an enclosure and using it to turn a light on and off, but I wouldn't want to be handling it while it was live, either! Regarding FCC/UL certification, a product is exempt from FCC certification requirements if it's "A digital device used exclusively as industrial, commercial, or medical test equipment", which most development boards are. I've got some dev boards from Microchip on my bench right now which aren't FCC or UL listed, either.
- tripletao 6y ago
  A digital device is defined as: > (k) Digital device. (Previously defined as a computing device). An unintentional radiator (device or system) that generates and uses timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second and uses digital techniques; ... https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pdf/CFR-2009-title47-vol1-part15.pdf https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pd... This has Wi-Fi, so it's an intentional radiator, so it's not a digital device. I believe this product would be technically noncompliant if not certified, though lots of stuff like this gets sold and I've never heard of any enforcement action. Their best counterargument would be that it's a component and not a self-contained product. That seems true for many dev boards but not particularly true for this one. Since the practical risk of interference is extremely low, I'd guess the FCC is happy to leave this grey for now.
  - R0b0t1 6y ago
    Test and measurement supersedes intentional emission. If it were the other way no development boards would get sold, especially necessary things like low volume engineering samples. Should a one-off need certification before it can be transferred to the company that contracted the work to build it? No. If you have never sought certification know that it is quite expensive. What seems to matter the most is if anyone actually notices interference, and if they do how widely the device ended up being sold. If a test and measure product starts making it into everybody's house eyebrows will be raised. If you misuse a test and measurement device and generate interference it is typically on you.
ohazi 6y ago
A decent heuristic for whether or not a wireless module has been FCC certified is whether or not the RF components are under a metal shield: If it doesn't have a shield, it's almost certainly not FCC certified. If it does, it's more likely to be certified.
Gibbon1 6y ago
One way to deal with high voltage is to use an external hockey puck solid state relay. Keeps the high voltage off the PCB and you don't have the kick from the relay coil finding it's way into the digital logic.

pdabbadabba 6y ago

> * Is it FCC-certified? It would certainly appear to lack the FCC ID label/marking it is required to have if it is FCC certified. So probably not. Thus, it also appears doubtful whether it can legally be marketed or sold in the U.S.

conk 6y ago
A search for "Malouf" on the FCC registration website provided no matches. Most likely this product is not registered. In addition, this product lacks a CE mark and has no UL/FM/CSA listing. I'm curious what creepage/clearance requirements were factor into the design. This product is potentially dangerous if the relay is switching line voltage.
- deleted 6y ago
  [deleted]
simcop2387 6y ago
IANAL, But I think device as-is can likely be sold and marketed perfectly fine. Test-kit and dev-kit stuff is regulated a bit differently under the assumption that it's not going to be in mass use, and also that it's likely going to be used to develop another product that will get the fcc certification. https://emcfastpass.com/fcc-rules-kits-subassemblies/ https://emcfastpass.com/fcc-rules-kits-subassemblies/
- pdabbadabba 6y ago
  The link you provided appears to say the opposite about kits: "Based on the definition above, it looks clear that non-authorized kits that are intended to form a complete product when fully constructed are technically not legally permitted to be sold in the US. That is because if you are marketing and selling a kit to an end user, which the user will then build into a full product, there is no reason to suspect that the normal rules would not apply." The subassembly rules could work, if they apply, but I don't see how this product fits the definition of a sub-assembly: "No authorization is required for a peripheral device or a subassembly that is sold to an equipment manufacturer for further fabrication." In fact, I think it's a stretch to say that any of these test-kit, dev equipment, or subassembly rules apply. This basically strikes me as being marketed as a consumer product -- albeit a product for very tech savvy consumers.
  - sokoloff 6y ago
    I don’t believe that dev board is a complete kit by the meaning of that rule. Certainly there is ample precedent for other dev boards (intentional and unintentional radiators) being sold without certification.
    - iancmceachern 6y ago
      Like everything on this site: https://www.tindie.com https://www.tindie.com
peterburkimsher 6y ago
This is the exact reason why I didn't see through my plan to build and sell the EspUSB (a very small ESP board that fits inside a USB-A port). I got 3 units built for myself by PCBWay at a cost of $77. I got quotes of ~$500 for 100 units from Elecrow and Makerfabs, but didn't know what to do with the other 90. Although I really want this great little gadget to be easily available, I can't afford $10,000 for FCC certification, and therefore I have no solution. If anybody wants more details, email espusb@gmail.com and we can chat about it on there.
- iancmceachern 6y ago
  I wonder how the folks that sell on Tindie get around this... https://www.tindie.com/ https://www.tindie.com/
  - tesseract 6y ago
    There are various exemptions for subassemblies and other non-end-user products. Those may not always apply. However, in practice, a product that's sold in small quantities and does not in fact emit egregious electromagnetic interference is unlikely to attract enforcement attention. So a fair bit of skirting of the rules does go on.
    - peterburkimsher 6y ago
      Based on the PAL project and WiFi capability, I think the ESP8266 does emit electromagnetic radiation. Whether it's interference or a feature depends on your perspective.
  - deleted 6y ago
    [deleted]
- antoniuschan99 6y ago
  What about using a pre-certified module (eg. Wroom-02 or wroom32)
  - 6y ago

conk 6y ago

I don't see any benefit in using an optocoupler. Using a transistor with flyback diode for protection is acceptable. Both the relay and ESP8266 are powered from the same 5V source, adding an optocoupler is not really isolating anything.

elcritch 6y ago
Sometimes it’s easier to deal with a combined part than two parts. It can reduce assembly costs for small volumes, or if the person doing the design is just familiar with the opto.

LeifCarrotson 6y ago

Regarding your first point, the relay has 2,000V of coil-to-contact isolation: https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf https://omronfs.omron.com/en_US/ecb/products/pdf/en-g5le.pdf Though it does look like the clearance/creepage distances on the PCB to the low-voltage ground plane are not any wider than 2mm or so, which is acceptable for 120VAC, but not acceptable for 240VAC per IPC9592. I wouldn't worry about sticking this in an enclosure and using it to turn a light on and off, but I wouldn't want to be handling it while it was live, either! Regarding FCC/UL certification, a product is exempt from FCC certification requirements if it's "A digital device used exclusively as industrial, commercial, or medical test equipment", which most development boards are. I've got some dev boards from Microchip on my bench right now which aren't FCC or UL listed, either.

tripletao 6y ago
A digital device is defined as: > (k) Digital device. (Previously defined as a computing device). An unintentional radiator (device or system) that generates and uses timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second and uses digital techniques; ... https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pdf/CFR-2009-title47-vol1-part15.pdf https://www.govinfo.gov/content/pkg/CFR-2009-title47-vol1/pd... This has Wi-Fi, so it's an intentional radiator, so it's not a digital device. I believe this product would be technically noncompliant if not certified, though lots of stuff like this gets sold and I've never heard of any enforcement action. Their best counterargument would be that it's a component and not a self-contained product. That seems true for many dev boards but not particularly true for this one. Since the practical risk of interference is extremely low, I'd guess the FCC is happy to leave this grey for now.
- R0b0t1 6y ago
  Test and measurement supersedes intentional emission. If it were the other way no development boards would get sold, especially necessary things like low volume engineering samples. Should a one-off need certification before it can be transferred to the company that contracted the work to build it? No. If you have never sought certification know that it is quite expensive. What seems to matter the most is if anyone actually notices interference, and if they do how widely the device ended up being sold. If a test and measure product starts making it into everybody's house eyebrows will be raised. If you misuse a test and measurement device and generate interference it is typically on you.

ohazi 6y ago

A decent heuristic for whether or not a wireless module has been FCC certified is whether or not the RF components are under a metal shield: If it doesn't have a shield, it's almost certainly not FCC certified. If it does, it's more likely to be certified.

Gibbon1 6y ago

One way to deal with high voltage is to use an external hockey puck solid state relay. Keeps the high voltage off the PCB and you don't have the kick from the relay coil finding it's way into the digital logic.