Reducing costs

In an effort to reduce costs more we investigated possibly doing a single sided board with all through hole components and then using our lab's cnc milling machine to actually route the boards rather then having them fabbed.

Cost of singled sided copper pcb per square inch = 5 / (6x12) = 7 cents/inch^2

If we panelized the (6x12) board we could probably get 2x10 = 20 boards

So our effective (material) pcb costs would be 5/20 = 0.25 cents/pcb

Using our CNC machine as a plotter we could etch the boards which would be faster and wouldn't have to worry about router bit costs which are ~10 a piece.

So for more time spent preparing the boards we could get the costs down by about $2.00 a board.

Estimated Costs:
PCB - $0.50 (once you factor in boards that will not etch properly and board cutout and drilling bits)
Switches - $0.29 x 3 = $0.87
Battery - $0.25
PIC - $2.00
SCR - $0.30
DISPLAY - $1.30
Resistors - $0.09 (for all)
------------------------
Total = $5.22

So, we're almost to our desired cost of $5.00.  I think we can find a LED display at a surplus electronics store for about $0.50. 

Single Sided Layout:

Update on Tuesday, May 18, 2004 at 03:43PM by Blake Robertson

On Digikey:
Found some other 10-Pin DIP Packaged displays that would save us $0.23 - $0.37 depending on whether or not we could get away with using a regular green display opposed to a high efficiency green display. 

MANC3440-ND

LED 7-SEG GREEN .3"

10-DIP

0.3"

0.86000 25

MAN3480A-ND

LED 7-SEG GREEN RHDP .3"

10-DIP

0.3"

1.07760

On ChipCatalog.com:
http://www.chipcatalog.com/Fairchild/MAN3440A.htm a similar display can be had for $0.39  which would save us nearly a dollar!  I'm waiting to hear back from them the quanity required to purchase them.