This morning I posted up a parts list and Mouser BOM (See Parts list tab above). And there is some good news / bad news from a cost standpoint!
Good news is: Basic component cost for the regulator came down a whopping $13.22 (to $29.72) through a combination of the simplified design and some more careful scrubbing of components selected. The bad news is changing from the low-cost HC-05 Bluetooth module to the RN-41 eat up all that savings, and the new combined component costs (including optional Bluetooth module) now comes to $54.67, a $6 increase...
So why again did I switch out the Bluetooth module? Two reasons: First and foremost is the HC-05 has no FCC certification. And given it also has no shielding there is a great probability this things is quit noisy from an EMI standpoint. The RN-41 not only has the FCC cert (plus other countries as well), it also has the needed shielding.
And there is another significant benefit of the RN-41, range. The RN-41 is a full-power Bluetooth with a range of several 100 feet, which the HC-05 is a low-power class of Bluetooth modules, with a best range of maybe 100'. Put it into a shielded engine room and that might get even shorter... If you do not need the extra range you can swap-out for the RN-42, it too has the FCC cert, is pin and firmware compatible, but as a short-range lower power device is $7 lower in cost...
I have real mixed feeling over the Bluetooth module. Perhaps once I finalize the design I will make up two PCBs - one for each - modify the firmware with some #defines and let you all decide which way you want to go.
Off course, a 3rd option is: Just built the board as it is today, but without the RN bluetooth. Order the HC-05 from Ebay and use jumper wires to connect it via the service port!
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