Electronic fireflies

My wife bought some of these and they are actually pretty cool but expensive for what they are.
The operation is there are 6 LEDs on long leads from a small plastic
box and 3vdc coming in
Each light comes on and dims out like it was on a capacitor for about 3-5 seconds.
The cycle time is pretty slow, maybe 15- 20 seconds each and somewhat random.
What's in the box? I am thinking the simplest relaxation oscillators possible firing a shot every now and then but how do they get the delay off? There is not much room for capacitors.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@aol.com wrote:

These days, a small microcontroller can do that job cheaper than the parts count of a discrete component solution.
A pseudo-random pattern and PWM modulation of the LED brightness is simple to do in software.
--
Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com
------------------------------------------------------------------
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 12 Jan 2013 22:00:05 -0800, "Paul Hovnanian P.E."

Bicycle rear tail light arrays as an example.
And those little "color organ" random light thingys for kids at the dollar store.
I still remember the 'speaker cabinet' style things with fluorescent lighting diffuser panels as a 'front screen' and 4 colored light inside. All wired to an analog audio amp which it lights when the music was above a certain threshold.
You want amazing on your hdtv?
http://www.soundspectrum.com/g-force/index.html?src=home
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.