Post by thread:[OT]rotating sculpture tangled wire problem

Hi everyone, I've been designing the electronics for a rotating interactive sculpture. There are two parts, a static base that acts as a turntable, and a revolving pink blop that sits on top. The base contains a dc motor and mains transformer. the top part contains a number of sensors (adapted from parking sensors from http://www.velleman.be) that switch relays on and off when activated to start the motor and change direction. the problem is that wires between the revolving top-part and the static bottom part get snagged and tangled as they are pulled round. There needs to be two wires supplying power to the sensors and two wires from the sensors to the relays. Can anyone suggest a solution to this problem... Surely someone else must have encountered it before? I am imagining something like rotating contacts but don;t know if these exist or what they'd be called if they did. Or maybe I need to communicate wirelessly between the sensors and the relays using RF? Any suggestions much appreciated. Sam. _________________________________________________________________ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Yes, there are rotating contacts, try a web serach to find them. And, as this is a PIC related list, I'd put a PIC to read your sensors, use three rotating contacts (power, ground common and serial communication - RS232, maybe, for better noise rejection) and another PIC to get the commands from the serial communication line and trigger the relays. Hope this helps Francisco sam woolf wrote: {Quote hidden}> Hi everyone, > I've been designing the electronics for a rotating interactive sculpture. > There are two parts, a static base that acts as a turntable, and a > revolving > pink blop that sits on top. The base contains a dc motor and mains > transformer. the top part contains a number of sensors (adapted from > parking > sensors from http://www.velleman.be) that switch relays on and off when > activated > to start the motor and change direction. > > the problem is that wires between the revolving top-part and the static > bottom part get snagged and tangled as they are pulled round. There > needs to > be two wires supplying power to the sensors and two wires from the > sensors > to the relays. Can anyone suggest a solution to this problem... Surely > someone else must have encountered it before? I am imagining something > like > rotating contacts but don;t know if these exist or what they'd be > called if > they did. Or maybe I need to communicate wirelessly between the > sensors and > the relays using RF? > > Any suggestions much appreciated. > > Sam. > > _________________________________________________________________ > MSN Photos is the easiest way to share and print your photos: > http://photos.msn.com/support/worldwide.aspx > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hi, As an idea for coupling power up to the module that is turning you can check out this link. http://www.bobblick.com/techref/projects/propclock/propclock.html It involves some motor modifications but is an excellent idea. Communications with the upper turning portion could be RF but then of course, I'm slightly prejudiced there. John Wireless CAN with the CANRF module. www.autoartisans.com/documents/canrf_prod_announcement.pdf Automation Artisans Inc. Ph. 1 250 544 4950 > {Original Message removed}

Russell McMahon wrote: > How much power (watts) do you want to transfer? > Inductive power transfer over distances of mm > to a few cm is quite easy. > Do you want continual rotation capability or just > say 360 degree rotation maximum? Navy guys have so-called "rotating transformers" (translation from Russian). They have 2 ortogonal windings on stator and 2 ortogonal windings on rotor. May be used for AC 400 hz power transmission, data transmission - varying frequency, determining degree of rotation when rotating by simple motor, also may be used as good rotating platform, as it has strong bearings. Mike. ------- When responding, keep in mind, please, this things may be under NDA. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Yes, a slipring would be the solution . You can buy (expensive) or try to make your own. One possible cheap suggestion that works because you only need 4 lines (and if your power requirements are low enough), pick up one of those inline gizmos to keep the cord to a phone handset untangled. Should only cost a couple of bucks, and should be readily available. regards, carl At 09:47 AM 7/12/2002, you wrote: {Quote hidden}>Hi everyone, >I've been designing the electronics for a rotating interactive sculpture. >There are two parts, a static base that acts as a turntable, and a revolving >pink blop that sits on top. The base contains a dc motor and mains >transformer. the top part contains a number of sensors (adapted from parking >sensors from http://www.velleman.be) that switch relays on and off when activated >to start the motor and change direction. > >the problem is that wires between the revolving top-part and the static >bottom part get snagged and tangled as they are pulled round. There needs to >be two wires supplying power to the sensors and two wires from the sensors >to the relays. Can anyone suggest a solution to this problem... Surely >someone else must have encountered it before? I am imagining something like >rotating contacts but don;t know if these exist or what they'd be called if >they did. Or maybe I need to communicate wirelessly between the sensors and >the relays using RF? > >Any suggestions much appreciated. > >Sam. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

This lokks like a very nifty solution! You may have some strong magnets fixed to the motor case and some coils at the moving part, so you can get a variable magnectic flux in the coils to get some alternating current (how much?). And you can add something like a transponder to send high frequency serial data ;-) Francisco Mike Singer wrote: {Quote hidden}>Russell McMahon wrote: > > >>How much power (watts) do you want to transfer? >>Inductive power transfer over distances of mm >>to a few cm is quite easy. >>Do you want continual rotation capability or just >>say 360 degree rotation maximum? >> >> > > Navy guys have so-called "rotating transformers" >(translation from Russian). They have 2 ortogonal >windings on stator and 2 ortogonal windings on >rotor. May be used for AC 400 hz power transmission, >data transmission - varying frequency, determining >degree of rotation when rotating by simple motor, >also may be used as good rotating platform, as it >has strong bearings. > > Mike. >------- > When responding, keep in mind, please, >this things may be under NDA. > >-- >http://www.piclist.com hint: The list server can filter out subtopics >(like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

No magnets, just feeding stator coils (or windings - what is correct in English?) with 400 hz AC. Rotor coils produce secondary 400 hz AC to feed moving part's electronics. Mike. Francisco Ares wrote: {Quote hidden}> This looks like a very nifty solution! You may have some > strong magnets > fixed to the motor case and some coils at the moving part, so you can > get a variable magnectic flux in the coils to get some alternating > current (how much?). And you can add something like a transponder to > send high frequency serial data ;-) > > Francisco > > > Mike Singer wrote: > > >Russell McMahon wrote: > > > > > >>How much power (watts) do you want to transfer? > >>Inductive power transfer over distances of mm > >>to a few cm is quite easy. > >>Do you want continual rotation capability or just > >>say 360 degree rotation maximum? > >> > >> > > > > Navy guys have so-called "rotating transformers" > >(translation from Russian). They have 2 ortogonal > >windings on stator and 2 ortogonal windings on > >rotor. May be used for AC 400 hz power transmission, > >data transmission - varying frequency, determining > >degree of rotation when rotating by simple motor, > >also may be used as good rotating platform, as it > >has strong bearings. > > > > Mike. > >------- > > When responding, keep in mind, please, > >this things may be under NDA. > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hi, What Mike is describing is similar to a CT (control transformer) or a synchro. If your project is a one-up, these are regularly available on e-bay. Regards, Dave Mike Singer wrote: {Quote hidden}> > No magnets, just feeding stator coils (or windings - what > is correct in English?) with 400 hz AC. Rotor coils produce > secondary 400 hz AC to feed moving part's electronics. > > Mike. > > Francisco Ares wrote: > > This looks like a very nifty solution! You may have some > > strong magnets > > fixed to the motor case and some coils at the moving part, so you can > > get a variable magnectic flux in the coils to get some alternating > > current (how much?). And you can add something like a transponder to > > send high frequency serial data ;-) > > > > Francisco > > > > > > Mike Singer wrote: > > > > >Russell McMahon wrote: > > > > > > > > >>How much power (watts) do you want to transfer? > > >>Inductive power transfer over distances of mm > > >>to a few cm is quite easy. > > >>Do you want continual rotation capability or just > > >>say 360 degree rotation maximum? > > >> > > >> > > > > > > Navy guys have so-called "rotating transformers" > > >(translation from Russian). They have 2 ortogonal > > >windings on stator and 2 ortogonal windings on > > >rotor. May be used for AC 400 hz power transmission, > > >data transmission - varying frequency, determining > > >degree of rotation when rotating by simple motor, > > >also may be used as good rotating platform, as it > > >has strong bearings. > > > > > > Mike. > > >------- > > > When responding, keep in mind, please, > > >this things may be under NDA. > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hi, You could make a rotating slipring assembly with a jack plug and socket. Depending on what the mechanical load is you can use the plug as the pivot in the base, and the socket as the bearing and electrical connection in the moving part. You can get 4-way jack plugs, or if you have a common ground then a three way (stereo) might suffice. I would suggest the 1/4" variety for strength, and I would imagine that this construction would not last for long, but then, it might be ideal for your application. Andy -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Filter [ot] as well, that's all. >From: Kieren Johnstone <spam_OUTmisterfugitTakeThisOuTHOTMAIL.COM> >Reply-To: pic microcontroller discussion list <.....PICLISTKILLspam@spam@MITVMA.MIT.EDU> >To: PICLISTKILLspamMITVMA.MIT.EDU >Subject: Re: [ot]rotating sculpture tangled wire problem >Date: Fri, 12 Jul 2002 22:31:46 +0100 > >OK, well if no-one will change it to "[OT]:" (which means its filtered out >for me), maybe "[EE]:", since its basically that anyway. > >Or maybe I'm just hot and bothered today... > _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

David Minkler wrote: > > Hi, > What Mike is describing is similar to a CT (control transformer) or a > synchro. If your project is a one-up, these are regularly available on > e-bay. Rotary transformer! Fantastic idea, every vhs VCR head assembly has a rotary transformer and precision bearings... I can just imagine the next wave of propellor clocks... :o) -Roman -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

I'm pleased to see that after a longish digression into electromechanicals (slip rings and ball bearings) we are starting to get back on track with rotary transformers :-) (I mentioned inductive power transfer, Mike Singer mentioned 400 Hz Russian military rotating transformers & Roman now mentions video recorders). Roman notes that all video recorders use rotary transformers in the heads - something I was unaware of but it certainly makes sense. I assume this is optimised for the several MHz video signal which is not a problem but I also imagine the power that can be handled is very low. So, I'll ask again - ???? How much power is this design meant to ???? ???? transfer to the rotating head? ???? The answer probably has a significant affect on which is the best. solution. Inductive power transfer is not very hard - especially if high efficiency is not absolutely essential. As an alternative to sliprings and their ilk it has many advantages. Russell McMahon -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Sat, 13 Jul 2002, Roman Black wrote: >David Minkler wrote: >> >> Hi, >> What Mike is describing is similar to a CT (control transformer) or a >> synchro. If your project is a one-up, these are regularly available on >> e-bay. > >Rotary transformer! Fantastic idea, every vhs VCR >head assembly has a rotary transformer and precision >bearings... I can just imagine the next wave of >propellor clocks... :o) >-Roman You'd be hard pressed to pass enough power to light a LED with those. Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.