Hi, Rx

Sorry for NOT having read all your explanations in details ( Difficult for me to read BIG pieces of prose on the screen ...)

BUT

There's one thing I didn't see in all these posts ...

use a RC filter between Relays supply and Pic Supply ... Small R ( 10 - 100 Ohms ) not to drastically reduce PIC voltage and BIG C ( 1000 + µF -Low ESR is best- ).

The only Drawback is to power the possible Leds from the relay side of the RC Filter ( inverted logic, then ) ... not too difficult, in fact; and also use an external ref. for ADCs.

For ULN 2x0x ... keep in mind those are Darlingtons outputs ... so Vce sat ~1 v ... 5v - 1v = not so much for 5v relays ...

Now ... for the Ice Cap ... nothing keeps you away from using a switching regulator like LM 2575 ... instead of a linear low drop '2940.


In the end ... do not forget to play the S.Gainsbourg 's tune "Melody Nelson" ... more than perfect for THE Phantom atmosphere.

Alain