I woke up one morning, looked up at my ceiling fan and wondered "what time is it?" With a bit of not-so-terribly-original engineering it would be possible to attach an array of LED's to one or more fan blades and create a time display similar to some "propeller clock" projects that I have seen on the internet.
With a bit of slightly more clever engineering, creative placement of the LED's and a little polar-to-rectangular tap dancing, it would be possible to produce a more conventional (non-skewed) display of images from the rotating arrangement of LED's. Probably useless for the average home but potentially useful for display of product logos and simple animations for advertising in dimly lit environments such as night clubs, restaurants, etc.-- half, Sep 10 2002 Ceiling Fan http://www.ceilingfan.comVery cool and inventive idea! [kelly23, Oct 04 2004, last modified Oct 05 2004] (?) Hokey Spokeys http://www.xenoline.com/hs.htmlBicycle idea [stringstretcher, Oct 04 2004, last modified Oct 05 2004] Baked (1) http://microtron.or...Projects/Whirlygig/There WAS a company that was making large rotating LED displays. I'll keep looking. [Vernon, Oct 04 2004, last modified Oct 05 2004] (?) Baked (2) http://www.act-thielmann.at/360Video/This is closer, but still not what I've seen out there. [Vernon, Oct 04 2004, last modified Oct 05 2004] (?) Baked (3) http://www.taesungd...20rsd/LED%20RSD.htmThis is more like it, but a little smaller than what I had read about. Certainly this would be fine for the ceiling (the large one was billboard sized). [Vernon, Oct 04 2004, last modified Oct 05 2004] Baked (4) http://www.seattler...oder/200112/srs.htmFor anyone wondering how it can be done (but still not what I'm looking for). [Vernon, Oct 04 2004, last modified Oct 05 2004] Baked (5) http://www.siggraph...1/venues/etech.htmlSpinning LEDs can even do 3D images (but I'm still seeking that 2D thing). [Vernon, Oct 04 2004, last modified Oct 05 2004] Baked (6) http://www.radiosha...&catalog=RadioShackRadio Shack will sell you a monochrome "Gamma Disc"... [Vernon, Oct 04 2004, last modified Oct 05 2004] Has been done (not by me) http://www.instruct...ng-Fan-LED-Display/Instructables.com - Ceiling Fan LED Display [half, Jul 23 2009] It's already been invented by the french http://www.cfdu.org/ [normzone, Jul 23 2009] Ceiling Fan TV Ceiling_20Fan_20TV [theircompetitor, Aug 31 2015] Well, you might be able to display a facsimile of an analog clock face. I'd like that. (+)-- bristolz, Sep 10 2002 I think this is an ingenious idea... not so much for home use, but where the public's eye falls. Extending on the idea, hot cities can have huge fans on the streetsides; the expenses for which are borne by the advertiser on the fan blades.-- joker_of_the_deck, Sep 10 2002 With even more clever engineering a man in a rocket pack could zoom around the city handing out self powered LED displays that show a picture of a donkey kicking over a top had full of mustard, why anybody would want to though is beyond me.-- Gulherme, Sep 10 2002 I was thinking the same thing, bris. Rather interesting idea.
And as far as I can determine, this is not a college radio station in Canada.-- waugsqueke, Sep 10 2002 Neat idea. Utilitarian, practical. Croissant.-- 8th of 7, Sep 10 2002 What 8th said.-- iuvare, Sep 10 2002 Half, what an amazingly cool clock! I want one...And by this I mean both the one you halfbaked and the one you linked...
StarChaser, lover of oddball clockery.-- StarChaser, Sep 11 2002 Don't just leave it as a clock; use it to display messages to the kids, hubby, wife, babysitter, dog, cat, fish...-- RayfordSteele, Sep 11 2002 I would buy this for home use. Stock quotes, weather reports, a disk of information, keyed to your interests. +1.-- Brackforn2, Sep 11 2002 You could do this with helicopters instead of skywriting.-- FarmerJohn, Sep 11 2002 In effect it's just an inside-out Baird-system video display.-- 8th of 7, Sep 11 2002 Actually [8th of 7], it's a wonder no one's suggested a Baird TV on this site yet, together with a handy PAL/NTSC to Baird signal converter.-- hippo, Sep 11 2002 Croissant. But how do you commutate all those LEDs? Would probably mount microcontroller on the fan itself. Stationary permanent magnet, and a coil mounted on fan such that it gets an inductive kick every rev. Rectify and chop coil current to charge a little NiCad, run microcontroller from that. Same pickup gives you phase reference, accuracy should be okay if torque is smooth and moment of inertia is high as in a fan. Microcontroller could have bluetooth chip for upload of pattern or an IR reciever for remote control. Modern microcontroller/PIC plus digital multiplexer could easily give you 128 5mm diameter LEDs along length of a 700mm blade, 1.4 metre diameter sounds about the right size for a ceiling fan (dunno, don't need them in Scotchland. Funny how a Scot invented mechanical TV...)
Say blade rotates at 10 rps, and fan is 1.4m diameter. Tip speed 44m/s. To get 5mm circumferential accuracy at rim you need 10 bit polar resolution, you have 0.1ms to set up all your LEDs, plenty of time if you write in assembler. Hence memory per frame=512bytes, 16k would get you a nice movie featuring a donkey and a bucket of mustard. Course LED birghtness would have to increase with radius. All seems perfectly bakeable.
On second thoughts perhaps you just need a 128bit wide ROM chip addressed by a counter incremented by a multiply-by-1024 pulse generator triggered by coil pulse.
Now replace those red LEDs with tri-colour ones and store 3 channels of brightness for each one and you have a 1.4m diameter full colour display. Once you've got that far you mount it with a horizontal axis and watch it like a TV. Give it variable pitch and this could preciptate a whole new genre of "Wind-o-rama" movies.-- shameless_self_reference, Sep 11 2002 Once croissant, flashing brightly and spinning wildly. LED's pose a choking hazard for children under 4, so keep out of the reach of children.-- Mr Burns, Sep 11 2002 I've seen a clock like this. It was shaped like a metronome and when you flicked the swing arm thingy, the time would show seemingly suspended in mid-air between the two extremeties of the arms' swing. No idea how it worked but a rotating version sounds feasible. Maybe something to do with a strobing LED? So a bit baked, I s'pose.-- briandamage, Sep 12 2002 [ssr] suggests a rotation speed of 10 revolutions/second. You would need something like that fast to allow the image to persist. But I don't fancy a ceiling fan rotating at that sort of speed. Fair enough for little clocks, but at the larger scale, I have to say, not so practical. You'd need to put it in a cage.-- pottedstu, Sep 12 2002 pottedstu: If you have 4 or 6 blades, you can effectively divide the RPM by the number of blades. So a 4-bladed fan, for 10 RPS (=600 RPM) goes down to 150 RPM which is much more manageable.
You can commutate both power and control signals (modulated onto an HF carrier) across the motor windings from the stator to the rotor with very little change in the design. I'm not sure (if it's a clock) why you need to commutate the control signals, if you put the timekeeper in the rotor, with a small rechargeable battery. All you need then is a sync pulse from the stator to keep the flash rate correct.
Now I'm just going to sit down here quietly in this chair, sip my drink, put my $10 on the bar and watch UnaBubba stop it with his head .....-- 8th of 7, Sep 12 2002 FYI, quick Google search turns up CFdU = championnat de France des Universités. But unfortunately no Canadian radio stations... the acronym does appear to stand for some kind of Canadian socialist labor organization, but I digress.
The idea itself is good enough, so I shall crois it. Now find a way to incorporate this technology into everything that rotates: microwave turntables, record players, CD players, car tires... what a kickass world it would be.-- polartomato, Sep 13 2002 IVnick8or: I've deciphered your name; naughty, naughty.-- FarmerJohn, Sep 13 2002 [UB] - Bravo. Listening to Tavener's Song of Athene while reading your poem, truly mystical.-- PeterSilly, Sep 13 2002 UB: <Loud applause, calls for encore .... oh. >-- 8th of 7, Sep 13 2002 Wonderful. I am overauden.-- General Washington, Sep 13 2002 I would say I was filled with auden, but that's more Christopher Isherwood's bag.-- General Washington, Sep 13 2002 Saw a guy on TV who made a prototype 3D display unit based on the same idea. It consisted of a helix shaped plane that was spinned at high speed. Computer controlled lasers flash-illuminated points on the spinning plane from all sides. In this way it is possible to create moving 3D shapes in the tubular space that is created by the spinning helix. Unfortunately only computer generated shapes can be displayed for lack of a way to record anything properly.-- Ehrm, Sep 13 2002 There is a Guiness bar fan that does something like this, ie words on the fan. As well as some for bike wheels that make patterns, just cant get them to google up! Apparently a lot of people are "Guiness Fans!"-- PiledHigherandDeeper, Jun 05 2003 The idea is excellent but can we really make it cost as much as regular clocks?-- nomadic_wonderer, Nov 14 2003 Great idea, the LED's could work in both "propellor" and "static" modes, so regardless of wether the fan is on or off, you still get the data. A fan shaped + coming your way.-- Micky Dread, Nov 16 2003 This could be plugged into your USB port, and display your instant messenger. Would probably Big in Japan (tm). Croissant from me.-- MaxMad, Nov 17 2003 Build one into the wheels of your car, and charge advertisers for the privelege.-- Alcin, Nov 23 2003 sounds like a blast. Incorporate them into the latest plexiglass tower cases and have built in graphical sound analyser effects. this would also go well in japan, make the same thing for car stereos for noth americans!-- LED Prism, Nov 23 2003 Half-baked... for bicycles! Have a look at Hokey Spoke link.-- stringstretcher, Nov 23 2003 'fraid I don't see any of your links a baking this, [Vernon]. While they are interesting, none of them is a fan. I wasn't claiming to have invented the spinning display technology. In fact, my own link is to an existing spinning display device.-- half, Nov 24 2003 What happens when i plan not reducing the speed of the fan?-- nomadic_wonderer, Oct 15 2004 What's cool is since fan blades are "tipped" you could put one row of LED's on the lower edge, and one row on the upper, you could have 2 simulteous images projecting at different depths for a 3-D display.-- trekbody, Oct 15 2004 Missed this one. (++)-- 2 fries shy of a happy meal, Jan 11 2005 Cool!-- energy guy, Jan 11 2005 Here in Ottawa, Canada, one of the local radio stations is CKCU..close.
Cool idea. I like having the LED's on each blade of the fan, possibly an array on each to give the clock some depth.-- ayt, Jan 11 2005 The cat's not going to like this one.[+]-- skinflaps, Jun 27 2008 Stick a clock on the lamp below the fan ?-- popbottle, Aug 31 2015 random, halfbakery