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Electric blankets, Gratuitous complexity??

Discussion in 'Electronic Design' started by Existential Angst, Nov 10, 2012.

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  1. OK.....

    So ahm happier'n'a alcoholic workin the night shift in a Jack Daniels
    distillery.... with my 400# deep cycle battery, 1500 W inverter (sitting
    in the back seat of m'truck), and my brand new blue electric
    blankey-poo.....
    Now I can curl up in a fetal position -- in m'truck -- in compleat toasty
    comfort.....

    Now, don't ax me WHY I gotta curl up in a fetal position -- in m'truck.
    Just suffice it to say, if you had my yob, you'd be curling up in a fetal
    position in YOUR truck, too.

    Except for one thing.....
    My g-d electric blankeypoo dudn't WORK with my 1500 W fukn inverter!!!!!
    WTF??????

    And the reason quickly became clear: some electronics don't work with
    modified (read: shit) sine wave power.
    But, what electronics are in a g-d electric blanket???

    So I take apart the three-heat controller, and lo and behold, the goddamm
    thing looks like the motherboard of a small PC.... holy shit.... for a
    $25 blankeypoo????

    Tryna sleuth out the ""circuitry"" of this electric blanket reminds me of
    the two days I spent tryna fix a $2.00 flashlight.... unsuccessfully....
    holy shit....
    The blanket has three wires between it and the controller, but only two of
    the wires register continuity!! From which I surmised, via advanced Ohm's
    Law, that there is only one element in the blanket, and the controller
    actually does control voltage/current, ie, no switching among elements, cuz,
    well, there's only one element.
    ..
    AND, the resistance is in fact the "right" resistance, cuz the wattage is 60
    W (1/2 amp), and the ohms measure 230.

    So now I got an extree wire that I don't know wtf it does, amidst my awe of
    all this goddamm gratuitous complexity.

    Now, I do have an inkling surrounding this latest Conspiracy of Gratuitous
    Complexity -- whose fundamental purpose is, of course, to assfuck the entire
    Global Population up to their collective ileocecal valves, so that Orwell
    looks like summer fukn camp.
    It appears that this particular example (this blue electric blanket) of
    Gratuitous Complexity has to do with..... <shudder> <shudder> SAFETY!!!!!
    And of course the li'l CHILDREN.......

    Btw, a brief digression:
    You DO know that they now make crawling helmets for toddlers??? Yes
    indeedy, google helmets for babies crawling , and pick your link.
    Better yet, ORDER yours, right away, so's when you take the li'l future Wall
    Street predator-to-be to Montessori for his (first) pre-school interview,
    you'll be showing up correck.
    You yourself and the spouse should also wear matching bicycle helmets, as
    well, just to show Montessori that the whole Beaver family is indeed
    correck.....

    Back to this g-d blanket bidniss....
    This shit blanket, for safety (it is UL listed btw), SHUTS OFF
    automatically EVERY GODDAMM HOUR!!!!WTF?????

    I mean, look, the g-d blanket is a *whole 60 effingW*!!!! My goddamm BODY
    puts out more heat than that....
    fyi, Your BMR of about 1 cal/min is actually nearly exactly 70 W of heat....
    which is why 10 blustering assholes in a meeting room make the place so
    goddamm hot.

    So some dumb QA engineering fuckhead sed, Oh, OH, 60 W -- spread over **24
    sq ft of g-d blanket**, no less -- is MUCH too dangerous!!!!
    Sheeit, in that case, my 70 W of body heat puts me at risk for
    self-immolation, right???

    Fuuuuuuuck, they couldn't have timed it for 8 hours?? 6 hours???? 4
    hours????? WTF???????

    So now, some while after the blanket shuts off, I'll freeze my goddamm ass
    off, have furtive nightmares, wake up, and flail around for the controller,
    just to reset it.
    So now I can't even g-d SLEEP worth a goddamm, in my fetal position -- and
    if you knew how long it takes me to get in that fetal position (in m'truck),
    you'd realize this is really a significant issue.

    OK.... so NOW ahm gettin it:
    SAFETY, and our precious li'l bratty g-d CHILDREN, require a solidstate
    automatic safety controller. Shitty li'l dropping resistors, or a xsformer,
    or split heating elements, just won't do it anymore.
    Now, they got a g-d controller in a $25 electric blanket that could have
    gotten Neil Armstrong to the g-d moon.

    Well, let me tell you, no one, but NO ONE messes with Angst's fetal
    position/sleep....

    So I took that controller off (via the detachable connector) and
    hard-wire-crimped a shit 18 ga wire with a shit 99c-store two-in-a-pack
    unpolarized plug, so now's I got *60 uninterrupted W* of blazing power,
    blasting thru my li'l blue blankeypoo. What a fukn triumph.....

    My gripe against Gratuitous Complexity harks back to my erstwhile 1971
    Datsun 510, which got better gas mileage than almost every effing car out
    here today, ceptin Volts'n'Prius'n'shit, and mebbe that VW TDI motor....
    AND, I could fix it my goddamm self.
    And I think I drove around Hawaii about 25 g-d times in a Datsun B-210, on a
    gallon of gas.

    Now, cars are so fukn complicated.....

    HOW COMPLICATED ARE THEY???????

    Cars are so fukn complicated, that factory Toyoter mechanics make more money
    than asshole college puhfessuhs..... AS THEY RIGHTLY SHOULD, cuz college
    professors are just absolutely fukn useless. goodgawd..... What a sham
    the college credit is, and a bankrupting sham at that.

    Cars now weigh 50% more than in the 70s.... and you can't even adjust the
    g-d IDLE!!!!
    Well, you can, I spose, with a laptop and about $1,000 worth of g-d
    programming.....

    Part of the Conspiracy behind Gratuitous Complexity is, imo, the desire to
    shut out the small entreepreeneer, bidnissman. A good fraction of the
    people on these ng's could *make their own perfectly navigable electric
    car*, with a welder, lathe, milling machine, some fukn batteries and a
    motor. Or mebbe just a welder, drill press, and an angle grinder....
    But fukn Chevrolet and Nisan barely got *their* electric cars out, the
    regulatory ante is so goddamm high. Near $40K for a g-d electric motor and
    a bunch of g-d batteries....

    So, inyway, Angst finally has his new blue blankeypoo blazing away, and I'll
    be fellatingly positioning myself in peaceful bliss tonite, in m'truck, with
    my 400# marine battery/1500W inverter right behind my blissful head.

    Oh shit, did I say "fellatingly"??? That would be "fetally", "fetally
    positioning myself in peaceful bliss".....
     
  2. Sylvia Else

    Sylvia Else Guest

    It's probably a triac style dimmer circuit - likely the cheapest way of
    making a three-heat electric blanket these days. It would indeed fail to
    work with a modified sine-wave.

    Sylvia.
     
  3. Sylvia Else

    Sylvia Else Guest

    Such circuits typically prevent current from flowing at all within a
    half cycle, until a point is reached where the remainder of the half
    cycle would deliver an amount of energy that would, if delivered over
    the entire half cycle, represent the desired power. Once triggered, the
    triac conducts until current drops below some smallish threshold.

    A circuit designed to do that with a sine-wave is going to be somewhat
    thrown by an input that is a modified sine-wave.

    Sylvia.
     
  4. Jamie

    Jamie Guest

    Or, just put a small transformer on the affected device.

    Jamie
     
  5. Mark

    Mark Guest

    I noticed the same thing during the recent power failure..

    The electronically controlled electric blanket will not run on my
    modified sine inverter.

    I think the third wire might be connected to a thermistor or
    temperature sensor in the blanket that the controller uses.

    If you don't mind wrecking the controller, you could wire the heater
    directly to the plug and use it on high... or wire in a switch with a
    diode and have full and 1/2. That would also defeat the timer
    function. Also beware this also might disable the overheat safety
    feature. I'd include a thermal fuse if I was going to do that. It's
    no fun waking up on fire.

    I'm thinking about designing a filter that will round off the modified
    sine enough so that the blanket can work with the inverter.

    Mark
     
  6. Guest

    The small standby UPS does no wave shaping when allowing the load to
    run on "line " voltage - and most are, at best, modified sine wave
    output.
     
  7. micky

    micky Guest

    Maybe he can find a "vintage" electric blanket. on ebay or a thrift
    store, pr criaigs list, or an "estate sale" (which iiuc is a big yard
    sale when the parents or grandparents die. Mine certainly has no
    electronics in it, just a thermostat that reads the air temperature,
    not the blanket temp. I don't use mine every year -- probably only 5
    or 10 --, but it's over 30 years old and working fine. I think his
    modern style might be only 10 years old, or less.

    I don't know what the new ones look like but my non-electronic
    controller has a clear plastic dial with numbers from 1 to 10, and a
    light underneath the dial that illuminates the number. If I try to
    use over 1.5 it's too hot in a bedroom that is 65^F. . Iff I take
    the metal back off the plastic case, it's clear how little is inside
    of it. No circuit board.

    Really older blankets might have a problem with low frequency
    radiation. I'm not sure if that was ever decided to be dangerous
    (causing cancer iirc after many years?) , but they changed the wiring
    arrangement anyhow so that for every wiire going one direction,
    there's a nearby wire going the other direction, to neutalize the
    raidation. AFAIK that works. and it's probably present in any
    blanket less than 20 or 15 years old.
     
  8. Guest

    What he NEEDS is a 12 volt blankie. My baby brother has been a long
    distance trucker across north america, from Alaska to Florida - and
    has 12 volt mattress warmer and 12 volt electric blanket for YEARS.

    Lost 'em both when he rolled the truck last year. Bust his neck too,
    but he's back on the road - doing mostly short haul flatland driving
    hauling crude - less than 2 years after the crash.
     
  9. micky

    micky Guest

    As I say above, in my experience high would be intolerably hot and
    even half temp, 5 out of 10 would be too hot to take, I've never
    used more than 2, but even in a truck cab with no other heat, I doubt
    anything more than 3 would be tolerable. He could test that in
    advance by using an extension cord from the house and sleeping in the
    truck with the blanket at half-temp.
    Really?

    JK
     
  10. tm

    tm Guest

    Well, if it has a poorly designed triac controller, it may radiate RFI.
     
  11. tm

    tm Guest

    Wouldn't that depend on your definition of "low frequency"? My AM radio is
    low frequency :)
     
  12. micky

    micky Guest

    Are you saying unless something is 3000 miles ong, it can't radiate
    low frequency?. I don't think so. And if that were the case, then a
    radio transmitter broadcasting at 600 KHz would require an antenna
    that was a third of a mile long.

    The question is not whether it can radiate, but whether the low
    frequency is harmful. This was the controversy that also centered
    around power lines, often just past the backyard of people's homes.
    But you do remind me that most of the opinion, or maybe the consensus
    arfter a few years, was that that was not harmful. By then electric
    blankets had already been rediesigned, since they were much easier to
    redesign than power lines. . But yes, they're no longer thought to
    be a risk, I think. I'd forgotten.
     
  13. Paul Drahn

    Paul Drahn Guest

    Our old electric blanket died several years ago. It had the bimetalic
    strip type control with the 0-10 dial. We loved it because we could turn
    it on an hour before going to bed and the bed would be toasty warm when
    we went to bed.

    It died and we got a new one and it would not preheat the bed. We
    returned it to the manufacturer and they said it was working fine, but
    sent a new blanked anyway. New worked the same way.

    I am convinced the thing knows when there is a body in the bed and when
    there is not. It can be on for hours and the bed is still cold when we
    go to bed. About 1/2 hour later, the blanket is warm, but we freeze
    until then. Real POS design.

    Paul
     
  14. Guest

    There ARE controllers that switch on the downward slope of the sine,
    greatly reducung theRFI.

    One thing for sure - an electric blanket sure plays havok with
    magnetometers, like in electronic compases - and electronic gyros.
     
  15. micky

    micky Guest

    I didn't know thtey had such things, but
    http://www.amazon.com/Heated-Fleece-Travel-Electric-Blanket/dp/B000V8QVX6
    http://www.walmart.com/ip/Maxsa-Comfy-Cruise-12-Volt-Electric-Blanket-Navy-Blue/10756183

    Onlly 25 dollars for each.
    They let babies drive trucks!
    Glad he's doing so well
     
  16. tm

    tm Guest

    It's best when they switch on the zero crossings.
     
  17. miso

    miso Guest

    I think we are feeding a troll (original poster), but yes, it is stupid
    to boost a voltage or go from AC to DC for a resistive heater. A company
    that I will not embarrass (plus I forget the name) was using a DC/DC for
    a heated stethoscope. [Hey Doc, do you keep that thing in the 'fridge?]
    Far better to get a heating element of the right resistance. And from
    what I hear, it is the speculum that needs heating.

    BTW, I've been to the Jack Daniels factory. It is worth the tour. The
    irony is the factory is located in a "dry" county, so you can't do any
    tasting there. [See what happens when you let Bible thumpers get too
    much power!] The factory is more like a college campus. Lots of
    buildings surrounded by patches of green grass. The whiskey is aged in a
    manner like you store explosives. The "bunkers" are away from the
    factory and have a buffer zone so that all the stock won't be destroyed
    should one site catch fire.
     
  18. tm

    tm Guest

    Got to know the transmitter engineers at NSS Annapolis. 24 kHz at 1 million
    watts. The ATU was in a building four stories tall.

    A friend of mine and I were instrumental in saving the three 600 foot self
    supporting towers on Greenbury Point at the Navy Academy property. The array
    was called a modified Goliath Array. The main feed went to a central 1200
    foot hot tower fed with four inch diameter litz cable. Six towers around the
    central tower were 800 feet tall and made up a capacitance hat. The hat was
    extended to the east to the three 600 foot towers.

    Two water cooled Eimac tubes made the power. They were amazingly small,
    maybe a foot tall. Cooled with deionized water in the anodes. A third tube
    was between the two that could be switched in if one of the main tubes
    failed.

    It was really sad to see the site decommissioned. A little bit of our
    history died.
     
  19. tm

    tm Guest

    You fucking nitwit. That rule was made by a consensus of the local
    community. It has no effect on you other than you couldn't get a free
    handout of booze. Typical libtard. Maybe you can ask obozo for free whiskey.
     
  20. I considered the 12V route -- blankets, heaters, seat warmers, all
    available, couild use the same deep cycle batt.
    But, I opted for 120 V stuff so I could use it inside the house as well as
    in the truck.
    But, the 12 V option might be better for some stuff. We'll see how it goes.

    I'm going to experiment with foiled-up 100 W light bulbs for heat, as well.
    Altho I also have a nice 9" Optimus parabolic heater, only 300 W -- don't
    yet know how to gauge wattage requirements of a small space that is exposed
    to the elements.

    My hot-wired blanket now works, and as far as the risk of fire goes, even at
    full blast, it's got a long long way to go before ignition... heh, famous
    last words, eh?? LOL
     
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