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Extra eyes on ESP32 Reflections ThingTwo main board?

frankcohen

Hi 14-ers, I'm seeking your help to review the third revision to the Reflections open-source hardware main board, codenamed ThingTwo. It's an ESP32-S3 in a 34 mm round double-sided board. This is my first-time to produce a hardware/software project. I'm excited and nervous. I would be glad for your eyes on the design: Identify mistakes, limitations, and poor design choices. And, make changes to improve it.

Schematic, layout, and BOM are at:

oshwlab.com/.../Reflections-Mainboard

The main repository is at github.com/.../ReflectionsOS.

I produced this to make mobile storytelling experiences. I am distributing the design under a free open-source GPL v3 software license.

Thanks for considering my ask.

-Frank

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  • I found the schematic difficult to follow as well.  For example, below is the GPS which is labelled "50 OHMS IMPEDANCE" instead of GPS.  I had to look up the part number to see what it was.  I was interested in seeing what the GPS schematic looked like because the previous version was said not to work.

    GPS

    The pin marked "ON/OFF" is not connected.  I'm not familiar with this part and don't know if that is acceptable or not but it should show a connection or be marked with an X flag to indicate it has no connection.  There are several other pins like this on the schematic and the design rule checker should be issuing warnings.  Ideally the GPS would be tested / prototyped before adding to the larger project which would reduce wiring and code errors.

    Have you had a good look at the power budget?  There won't be much room for a battery and some of the components are likely to be power hungry.  

  • in reply to fmilburn

    "For example, below is the GPS which is labelled "50 OHMS IMPEDANCE" instead of GPS. " I take your point, and well. I will work on cleaning up the silkscreen overall. And to your point about the impedance label it applies only to Pin 11 RF_IN. I'm changing the label and denoting GPS for the module.

    The Sox (rev 1) and Hoober (rev 2) GPS modules may have worked; However, the boards has so many fundamental problems - like Sox ESP32 not booting. I tested the ATGM336H-5N31 in a breadboard and it works great. It comes in a surface mount module, so much less testing and I chose it. 

    "Have you had a good look at the power budget?" Measuring current needs is coming up next week. I will report what I learn here.

    image

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  • in reply to fmilburn

    "For example, below is the GPS which is labelled "50 OHMS IMPEDANCE" instead of GPS. " I take your point, and well. I will work on cleaning up the silkscreen overall. And to your point about the impedance label it applies only to Pin 11 RF_IN. I'm changing the label and denoting GPS for the module.

    The Sox (rev 1) and Hoober (rev 2) GPS modules may have worked; However, the boards has so many fundamental problems - like Sox ESP32 not booting. I tested the ATGM336H-5N31 in a breadboard and it works great. It comes in a surface mount module, so much less testing and I chose it. 

    "Have you had a good look at the power budget?" Measuring current needs is coming up next week. I will report what I learn here.

    image

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