AVR-Chat

I think this should quite doable within a $12 BOM budget if not 
significantly below that.  If a standard LED is bright enough, you 
can drive the LED directly (assuming a 20 mA drain - less with 
flickering) so no need for a drive transistor. Internal oscillator so 
no xtal/caps.  I think you could run at 3V off 2 AA cells and mount 
the battery holder in-line on the pc board for a skinny "candle" 
format.  A length of white PVC pipe for the candle body and some sort 
of translucent diffuser at the top.  switch at the bottom the PCB.   
I'd probably use an 8 pin PIC rather than Atmel, just for cheapness 
sake. you should be able to get a gang of boards made for fairly 
cheap assuming a 6"x 1/2" format though you might have to sneak it by 
the board house.

Phil

--- In AVR-Chat@yahoogroups.com, tom@k... wrote:
> I know just enough about this stuff to be dangerous, so please bear 
with me if 
> my question is laughably misplaced.
> 
> I would like a circuit designed for an LED candle. I'll be 
producing about 100 
> of them, possibly many more, more, for my haunted house. 
Requirements:
> 
> - Flickers realistically
> - Works off standard 9v batteries (or 6v battery packs if 
necessary) for at 
> least 30 hours
> - On-off switch
> - Costs no more than $12 (and preferably less) to build total, 
including 
> populated circuit board & LED(s). In my fevered imagination, I hope 
that the 
> Atmel processors have pretty much all you need except for a couple 
of 
> transistors, resistors, and an external switch
> - LED doesn't have to be exact candle color (I can supply colored 
cellophane or 
> whatever it it's a white LED)
> 
> And ideally but not necessarily:
> - Fits without the power source in a candle
> - Would have an option to plug many of them into a chandelier and 
power from a 
> single source
> - Uses a bright LED
> - Has some sort of user adjustability for auto-off for power 
saving, and/or 
> randomness setting, and/or flicker speed
> 
> Would love to know if this is even close to doable in my price 
range, how much 
> you'd charge to design it, and where I should go to get it 
manufactured. Feel 
> free to contact me offline or to jeer at me publically.
> 
> Thanks!
> 
> Tom Campbell