FCC Regulations and Open Source Hardware

We’ve been doing some research into how we can sell our designs without needing FCC testing.  There are a number of exemptions called out in CFR47 15.103.

One of the more interesting exemptions is the one related to “digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz.”  We’ve read some discussion forums where some interpret this to include harmonics generated by the oscillator, which would make this exemption quite narrow in application.  However, there is a FAQ page at bureauveritas.com that seems to interpret this to mean “digital devices oscillating below 1.705 MHz.  See here (cached copy)  Take note of the answers to the following questions:

  • Can’t I be exempt from FCC regulations?
  • What kind of digital consumer products get exempted?

I’ve sent them a message asking if they believe the harmonics are excluded under this exemption.  I’ll update the post with their reply.

Another good resource on the interpretation of Part 15 is in the FCC’s OET Bulletin 62 (cached copy).

Update February 25, 2013

The response from Bureau Veritas is probably what you would expect: cautious with a slant for testing:

Digital devices using oscillator frequencies of 1 MHz (or even lower frequencies) are not necessarily exempt from FCC requirements. As you indicated, the potential for harmonics extending beyond 1.705 MHz exists, and these harmonics could conceivably emit at power levels that would require compliance testing.

Obviously, specific product design will ultimately determine the level of concern, but it is not a safe assumption that the oscillator frequency alone will define FCC exemption.

2 thoughts on “FCC Regulations and Open Source Hardware”

  1. Thanks for sharing your experiences with FCC so far. I am making some open source hardware designs too, and I was wondering, what route have you guys taken regarding FCC testing/not testing? Any more insight you’ve gained after the Feb 23 letter from the FCC would be helpful, thanks!

    1. FCC testing is a big expense, so we’ve always just done projects that we thought would be exempt. We evaluate each project we think about undertaking and consider how well it might fit into one of the exemption categories.

      • An Arduino shield (we think) falls into the “sub-assembly” category.
      • A stepper motor controller (we think) falls into the “appliance” category: especially as clarified in the FCC’s OET62 document linked to above.
        “Appliances” are devices that are designed to heat, cool or move something by converting electrical energy into heat or motion.

      • We’re working on a torque sensor that would fit the “used in a vehicle” exemption and the “test equipment” exemption

      After we think about how our project might qualify as exempt, we then try to find similar devices made by other companies and see if they have FCC certifications for their products. For example, we couldn’t find that any of the Gecko stepper controllers have gone through FCC testing. Same with the ones from Applied Motion Products: they seem to have only got their power supplies FCC tested.

      Another interesting exemption is the “electronic control system in an industrial plant”. “Industrial plant” is explained to mean a dedicated building (we wonder if a detached garage would qualify…) in OET62. A lot of projects (we think) would fall into this category. Many websites have you agree to terms and conditions as part of the checkout process. One could ask their customers to verify that their purchase falls into this category during checkout. The thinking is that it would at least let you get your product to market, and if it is well received by the industrial community then it might be worth it to get it examined for the non-industrial market.

      Also, you might want to check out the FCC caught violators website. The cases are an interesting read and the FCC definitely means business.

      Don’t take any of this as legal advice. We have no idea what we are talking about.

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