When we last left this narrative about the building of the HappyDay Energy Monitor PCB, I was not able to get the circuit that takes in the 120VAC provided by the L0 source.  It is another day.

To check my sanity, the first thing I do is a continuity test between the pads that participate in this part of the circuit.  Perhaps I do this just to hear the beeping.  I love it when the two pads beep.  Even when the chips haven’t been soldered on.  Of course, it is so much more comforting to hear beeping when the chips ARE soldered on.

All beeping aside, I found the problem….

Frustrated   Notice the pin connections of the RAC04-GA chip:


pin 2 connects to N, while pin 3 is NC.  Now check out my schematic:

I have identified two pin 3’s:


Curiously, the footprint has the N pin labeled 2 and the NC pin as 3. This is correct, but the schematic botches this….bummer.

Fine.  I messed up.  And that’s why Chris Gammel focuses on bodging in his excellent Contextual Electronics course.  Challenges bring so many opportunities. Here’s an easy one.  Jumper pins 2 and 3.:




ChallengesBringOpportunitesOoohhh!  YIPPEE!  The green LED lights up:


Here’s the 3.3VDC signal on my scope:


There is a 120mV Vpp.  According to the data sheet, the ripple should be ~ 100mV:


I should be ok.  Especially since the 3.3V going into the Feather goes through an LDO. 


Ever marching forward…..