Yes, there are 2 coils, one is on the base near the motor, the other is on the disk. The shaft of the motor goes through each coil and plugs into the disk. Cheesy ASCII Art: (disk)<-O-O-[motor] where <---[motor] is the motor in the arm coming off the base. O is a coil. The coils are side by side instead of one inside the other. They are the flat squished up coils (voice coils?). ttyl, Ben On Mon, 31 Jan 2005 19:41:51 -0700, tim_webb@agilent.com wrote: > When you say air transformer, are your saying that there is a coil rotationg withing a coil? > > -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf > Of Ben Hencke > Sent: Monday, January 31, 2005 3:38 PM > To: Microcontroller discussion list - Public. > Subject: Re: [PIC] Propeller clock motor, > > I have one of these, maybe an older version. An 8 RGB LED "Rave Disk" > or some silly name. > > The one I have uses an air coil to create a transformer. There is no > contact or rotary detector. > > The LEDs are driven by 2 dual BCD counters. There is epoxied blob chip > underneath that is used to control the signals to the BCD inputs. It > doesn't care how fast it is spinning, it will just look like it is > "shimmering" if you hold it still. It has 2 modes, changed via a > switch in the back of the disk. Also, the LED elements are just turned > on or off, so there are only 3 bits of color. > > I really want to hack it to display images ;-) > > It looks pretty neat, but mine makes an annoying high-pitched whine > from the air transformer. > > - Ben > > On Sat, 29 Jan 2005 01:46:29 -0700, Robert Rolf wrote: > > michael brown wrote: > > > > > > > > You two guys might be interested in this. I was killing some time > > > inside Spencer Gifts a couple of weeks ago while waiting on my wife to > > > get out of the eye doctors office. In the back of the store where all > > > the black light stuff is, they had an interesting toy. I guess you'd > > > call it kinetic art, but it greatly resembles the propeller clock > > > concept. It's a black spinning disk about 12" or so in diameter. It > > > has 8 or 10 RGB LEDs arranged in a straight line from the center out to > > > the edge. As the disk spins, it creates interesting segmented > > > multi-colored circular patterns. I believe they were US$29.00 (maybe > > > 39.00). > > > > > > What really intrigued me was that every LED was individually > > > addressable. I wanted to buy it just to see how they did their slip > > > ring coupling. I wanted to see if they literally had the 30 odd > > > individual contacts required to do the 10 or so RGB LEDs. After > > > thinking about it for a while with my "how cheaply could an engineer > > > make this" mindset enabled, I figure that they just spin the entire > > > electronics assembly and only transfer power (2 wires) thru the > > > coupling, otherwise the coupling would probably be the most expensive > > > part of the device. > > > > I have one. > > They just supply power to the setup with a single brush > > and an copper tape on the plastic hub. > > It uses a COB (chip on board, under epoxy) so there is no way to > > access the device to reprogram it. > > > > > It makes nice patterns while still coming up to full speed, so I figure > > > there is probably more than one disk position indicator. I'm thinking a > > > few magnets evenly spaced around the circumference of the disk and a > > > single Hall sensor. Or do you think they just use a single reference > > > point and factor in the acceleration to keep the pattern nice and evenly > > > layed out? > > > > Just a mechanical contact that fires once per rev. > > The acceleration is quite slow, but you can see the pattern > > jump if you drop power for a moment since it assumes a certain > > speed until it has completed one rev. > > > > > After telling my wife all about it, she says I can have one to "tinker > > > with". ;-) I wish to first see how it's constructed and then replace > > > the "brains" of it with something a little more useful, like an > > > analog/digital clock display that also does cute patterns that I like. > > > ;-) > > > > As noted above, you'll have to replace the COB with your own > > device, but it's a simple LED matrix. > > > > Have fun. > > > > Robert > > > > -- > > http://www.piclist.com PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist