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Breaking the law?

Discussion in 'Electronic Design' started by Tim, Feb 1, 2005.

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  1. Tim

    Tim Guest


    I want to play around with hardware so I bought a card from delcom
    engineering that allows me to flip some bits on a USB board. What laws
    do I have to consider to put out a simple electronic thingamabob that
    connects to the USB port or serial port? For instance, some LED
    sequencer that sequences the lights based on the PC software?

    I figure it will be fun to write all kinds of crazy software to drive
    the LEDs and I could sell this on a web page. But do I have to spend
    thousands getting UL certification, EMF testing, or what?
  2. Jim Thompson

    Jim Thompson Guest

    The easiest way around safety certification is to buy certified wall
    warts for your power source.

    ...Jim Thompson
  3. keith

    keith Guest

    As long as you can live in the power envelope (50VA?). That's what
    everyone else does, though they're a PITA for customers.
  4. You should check with the USB folks to see if there are any licensing
    issues with getting vendor and device IDs.
  5. John Doe

    John Doe Guest

    wall wart: n.
    A small power-supply brick with integral male plug, designed to plug
    directly into a wall outlet; called a ‘wart’ because when installed
    on a power strip it tends to block up at least one more socket than
    it uses. These are frequently associated with modems and other small
    electronic devices which would become unacceptably bulky or hot if
    they had power supplies on board (there are other reasons as well
    having to do with the cost of UL certification).
  6. Another thought is to sell your unit as a "component". For example, as a
    kit or a not quite complete assembly. I see quite a lot of stuff advertised
    that way.

    You could sell the display module and and have a link on your website to
    retailers of suitable power supplies. I suggest using a very common power
    supply value, such as 12V, so your units will work from a car battery, or a
    common 12V power supply. Make it easy and safe to get going.

    You can have a "wiring it up" section on your website where you show
    pictures of a module hooked up to a power supply and a computer - and a bit
    of discussion.

  7. The USB board will already have a legitimate ids, so you are covered.

  8. Guest

    Safety certification is one thing. EMI testing is another. FCC testing
    is a bear.
  9. Joerg

    Joerg Guest

    Hello Larwin,
    It doesn't have to be. Just make sure nothing can leak onto the power
    cable and the device itself is quiet, with a nice ground plane etc.

    I found EMC cert to be pretty straightforward. Sometimes even relaxing
    and uplifting, for example when the site was out in the boonies with
    great views, wildlife, no traffic.

    Regards, Joerg
  10. keith

    keith Guest

    It paid my mortgage for a couple of years. I had some really cool toys,
    a small lab of my own, off in the corner (where I decided it was quiet
    "enough") and all I had to do is test motherboards and processors for EMI
    strangeness (I found a buunch too). Ah, well, it was too good to last.
  11. Guest

    The campus where I work has their own FCC open-air test site (we do
    self-cert), and part of my newbie orientation was to observe and assist
    in testing of a couple of products. The process itself is simple enough
    (though repetitive and a bit boring), but it's the COST - for a
    small-run semi-hobbyist article - that is utterly prohibitive. I think
    our OATS cost about $150,000 to build (not counting the actual
    structures that it's built on and in - that's just equipment,
    integration, calibration and testing).
  12. keith

    keith Guest

    I'm surprised it's that little. My pre-qualification equipment was
    $50Kish. That was only a 6.5GHz HP EMI analyzer and a couple of antennas.
    Receivers were *far* more expensive and less versatile.
  13. Joerg

    Joerg Guest

    Hello Keith,
    Why didn't it last? My impression is that EMI is becoming worse, not
    better. Besides the usual such as split grounds, lack of awareness and
    so on there are ever rising clock speeds and the proliferation of
    plastic enclosures. Then those nice switchers with EMI claims that are,
    well, a bit stretched.

    The plots I receive after a blown compliance test are generally worse
    than those I got ten years ago. And the work to bring someone's design
    into compliance has become tougher.

    Regards, Joerg
  14. Joerg

    Joerg Guest

    Hello Lewin,
    That's why most companies do not own a compliance lab. You have to have
    good pre-compliance results and some basic gear, get the margins well
    below the legal limits and then head to a service provider with a 'real'
    EMC lab. If you pass on the first test run you can be home for $10-20k,
    depending on what else has to be tested.

    Of course, if a company cranks out a brand new product design every
    couple months or so that is another matter. At the end it all boils down
    to how fast the lab would amortize versus the accumulating expenses for
    service providers.

    When I am called out to a client with an EMC problem we mostly use quite
    basic gear and dinged-up rental antennas that had seen better times. But
    in all cases it passed with flying colors at the EMC site, mainly
    because we shot for >10dB margins on conducted and >20dB for radiated,
    at least for stuff above 100MHz where patterns are less predictable.

    Regards, Joerg
  15. Fabless partner sold out to other big semi company. We closed up shop,
    Tougher => more demand => more $$
  16. Joerg

    Joerg Guest

    Hello Keith,
    Yes, the famous mergers. And often you see an immense slowdown
    afterwards, less new stuff, longer cycles between new products and so on.

    But crushing analyzers? Oh man. Why didn't you just keep them?
    Well, either that or someone decides the project needs to be scrapped.
    Other times it just keeps dragging on.

    Regards, Joerg
  17. Guest


    I'm probably on the low side, because $150K is what we paid to
    refurbish it. But I think most of the crucial stuff was replaced in
    that refurbishing - antenna, remote antenna height/polarization servo,
    remote-controlled turntable for UUT, spectrum analyzer and signal
    generator. The only things left from the old OATS were buildings and
    maybe antenna cables.
  18. Guest


    We're a bit more complicated than just spurious emissions testing - we
    do a _lot_ of Part 15 devices and in a lot of cases "special" testing
    is required to guarantee, for example, occupied bandwidth. So we need
    to get down and dirty with what's being radiated; looking at the exact
    spectrum while the device is in different modes, checking frequency
    deviation for FSK devices, derating power levels for signal duty cycle,
    ...., ..., ...

    At any moment there are usually about two items in the queue for the
    test site. I guess we probably do twenty new transmitters or
    transceivers per year? (just a rough guess and probably on the low side
    - my team is a *very* small segment of the campus, about 5% of the
    total engineering manpower, and we do maybe four products a year. All
    our products are transceivers or receivers).
  19. keith

    keith Guest

    Particularly when a particular large multi-NATIONAL SEMICONDUCTOR company
    bought the line and then failed miserably trying to get it all working
    One doesn't argue with Sir "Counter of Beans" under penalty of law. All
    capital assets must be destroyed if they're written down. Yeah, I would
    have made a corner in the basement for 'em, but that wasn't happening. A
    colleague in another site (same division) wanted my toys, but would have
    had to have the equivalent $$ approved by his CoBs to "buy" 'em. Since
    it was layoff season one didn't fight o-great-one-with-purse-strings on
    Ah, Sir Counter of Beans, again. ;-)

    Chances are that if it doesn't pass quickly it may never and perhaps
    should be scrapped. Sunk costs are sunk. Flushing good money after bad
    is worse than the flushing of bad money.
  20. <>) about 'Breaking the law?',
    That's 'LORD Counter of Beans', and don't you forget it!
    So don't write them down! Sell them as used equipment. Even getting 10%
    means MORE MONEY, which makes the noble Lord happier.
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