Chasing circle of LEDS...?

I'm in the process of making a UFO model for the local Railroad museum's model trainset.  What I want to do is have the standard disc shaped UFO with embedded LEDs on the edge.  I would like the LEDs to chase around the edge repeatedly while the display is on. 

I've looked into using Arduino, but size is a factor.  The UFO is going to be about 6" across.  As far as I can tell, I can use a 555 and 4017 to work it out, as but that limits me to 10 leds, right?  

If it can be worked out, having counter rotating circles would be great... But that would be duplicating the circuit and reversing the 4017 pin outs...

AND...where is a good place to buy small quantities of LEDs and ICs?  My local Radio Shack has nothing in stock

You can add more LEDs by reverse connecting LEDs making one more circle of LEds. This will provide some nice effect. Look for more current though !
You only need ONE 4017, driving LEDs in groups of 10 - the illusion of movement will be fine. You'll need to beef up the 4017 output current though, I suggest you add a ULN2803 to it.

frollard5 years ago
There is a way to cascade 4017 with an inhibit but it's more trouble than its worth. There is an expandable shift register circuit on bowdens hobby circuits;
It involves using hct164 shift registers, and when it powers on a one-shot circuit loads a bit into the first led, then pulsing the clock cycles it down all the (expandable) stages...if you connect the end to the beginning you get your desired effect.
http://www.bowdenshobbycircuits.info/page5.htm#shift.gif look for "expandable 16 stage led sequencer"

Arduino nano or 'teensy' is the way to go if it's gotta be really small, expandable, and programmable

Small quantities I always goto ebay or dealextreme -- you can get 100 leds shipping included direct from manufacturer (china) for 5 bucks. Chips, you're stuck with suppliers like digikey, mouser, newark and the like -- most of which are affordable but expensive shipping.

As for an arduino sequencer, it can reasonably switch hundreds of leds for a simple project like this.