Sure, but sadly I don’t have a proper schematic…what I do have is this partially hand-drawn “schematic” that depicts a bit more wiring detail. Note that the drawing doesn’t show the TCA9548A board that I added later, after I had already built them to that plan. The TCA board got added because of an issue I had with I2C errors (see that earlier thread in case it’s relevant: Notecard not responding + I2C error messages - #11 by noforan). I can make an updated diagram to include the TCA board, if really needed, but essentially the SDA/SCL lines from the Notecarrier now route to the TCA board and then individual pairs of SDA/SCL mux connections then go to the EZO boards.
I have seven of these devices all built more-or-less identically, and only this one shows this problem, which makes me think that if there’s a wiring problem, it’s probably with this specific device. I have made a custom PCB that replaces the manually soldered breadboard that I started out with, so maybe I’ll replace it with the PCB as a start and see if it resolves it, or at least I’ll need to go back through all the cross-connects to make sure nothing is mis-wired. But that’s all downstream of the Notecarrier.
Where would 12v come from? All the peripheral boards ultimately get power from the Notecarrier 3V3 pin/GND. And the Notecarrier is getting power from one of three sources depending on what I’m doing, either:
- The 3.7v LiPO battery / Solar panel – if the device is in the field
- The Swan USB / PC – if I’m testing code or doing sensor calibrations
- The Notecarrier USB / PC – if I’m checking the Notecard in particular
Do you have maybe a suspicion of what I’d be looking for in terms of bad wiring that would be feeding the Notecarrier 12v? Is it possible for the “downstream” wiring to backfeed the Notecarrier and cause this?
