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How to make Open Source hardware products CE certified?

Creating a product is fun, making it open source is even more fun. When it starts to sell, you feel you did things right. The question however, did you really did it right? Do I comply with all requirements defined by the European Union? Did I perform the necessary tests? Is it certified? Can I safely put the CE mark on my product?

One of the important aspects when creating open source hardware that you want to sell in Europe is the compliancy with the requirements defined by the European community. These requirements are assembled in multiple directives. The type of product will define which directives are applicable.  A product which is not compliant cannot be sold in Europe!

These compliancy, especially for hardware, will make sure the product is safe, that the radiation of the product remains within the defined limits and that the product can support certain levels of radiation without failing.

How to become CE compliant?

You have 2 ways to become CE compliant:

  1. Self-certification: You perform all the tests yourself (by using your own test lab or by renting a test lab), assemble a complete file which proves compliancy and sign the self-certification declaration. Many test center exists which have the specialized equipment to perform all the necessary tests
  2. Certification by a notified body: A notified body is a test lab that is approved and certified by the European Union. You can use this test lab to fully test your product.

Please note that not all products can be self-certified, it all depends on the type of product. For example medical equipment, elevators etc cannot be self-certified.

Some companies did buy the test equipment themselves to be able to perform their tests but these are real exception due to the high investments required. In reality, you will always need a test center to prove compliance of your product.

Guidelines we used to get the OpenMotics products certified

Since using these type of test labs cost quite some money, it is key to be very well prepared already in the design phase so no costly re-certification is needed.  Here are some of the guidelines which we used to get the OpenMotics products certified:

  • Protect all inputs with filters: 
    • what
    • why
    • how , schematics
    • tips
      • voltage supply connection is also an input. 
  • Safety distances ()
    • what
      • between ELV and LV
      • LV and LV
    • why
      • kruip
    • how
      • depend on PCB or airgap
      • example with output module screenshot
    • tips
    • Watch dog timer (difference between keep working and recovering from working)
      • Not only total reset,
      • If no connection for some time -> also do a reset of the communication system or even from the processor.
        • I2C/UART/..
    • Beveiliging tegen bliksem (is this also under ESD? otherwise split)
    • Filtering tegen uitstraling
      • especially on connections with long wires (which happen alot in home automation)
      • Filter to reduce the radiation in both directions
    • general tips
      • I2C dont use it externally, use CAN/RS485
      • pull up choice.
      • Dont use higher clockspeeds than needed, for processorspeed and communicationspeed
      • Bootload possible

    Getting our open source hardware modules certified

    The Open source hardware modules are certified by using 6 steps:

    1. Identify which directives are applicable for each module: Not all products required to be CE certified so we need to check each of our modules to fall in at least one CE marking directive. If not, no CE marking is needed.
    2. Identify the applicable requirements of the applicable directives: Each directive has it’s own methods of demonstrating conformity. This usually depends on the classification of the product and its intended use. Every directive has a number of essential requirements which the product has to meet.
    3. Identify the route to conformity: The CE marking process is always a self-declaration process however it can be needed to involve a third party. This is described in the “system of attestation” and will vary between directives.
    4. Assessment of the product’s conformity: When all the requirements have been met, you need evidence that the product meets the essential requirements of the directive(s)
    5. Compile the technical documentation: This information should cover every aspect relating to conformity and should include design, development and manufacture of the product.
    6. Make a declaration and affix the CE mark: When the product satisfies the applicable CE marking directives as they must complete a declaration. 

    Put CE logo on the devices. There is only one correct logo:

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