Peter Todd wrote:
> 
> I'm working on the basis that I can implement that each node will have
> something like the following part list: (digikey prices)
> 
> $1 - 10f200 SOT23-6 package (maybe, depends on solderability by
> 		students)
> $0.25 - led of some sort
> $0.10 - diode
> $0.10 - capacitor
> $1.75 - 1"x1" pcb, qty 100
> $?.?? - conformal coat of some sort
> $0.00 - student labour to assemble it all...
> 
> $3.20 a node.
> 

I did this exercise a while back and have similar results.  My numbers 
look roughly like this:
$0.05	- 1 capacitor
$0.05	- 5 resistors
$0.94	- PIC10F206
$1.20	- RGB LED
-OR-
??? for 3 discretes leds
$1.00	- PCB
$0.75	- RJ45 jack
-----
$3.99/node
This could be less if better source for the RJ45 was found.  The pcb's 
could be phenolic/paper fabbed in China.  Pay your money and take your 
choice.
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