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Since I received GREAT feedback on my first PCB design here (and it works!) I have decided to design a second (improved) version.

In this version I would like to be able to measure the source battery voltage so I can translate that to an estimated battery capacity.
For this I'd like to use the ADC pin on the ESP12. On this pin I made a voltage divider because it only measures up to 1V.

Is this a working and the best approach for a beginner to estimate source battery capacity on the ESP12?

Someone suggested placing a .1Uf capacitor between GND and where the ADC reads. What would this do?

To get around the strain on the battery caused by this divider setup, should I put it behind a NPN tranistor?

enter image description here enter image description here

the source files are all in the project on GitHub

Trace Thickness
enter image description here

Did I make a mistake here?

EDIT - Thicker traces and antenna free
It also looks like this voltage divider is ok, I have tested it on a breadboard. The voltage divider power consumption is 0.0074mA if I calculated that right :) [Thicker traces and antenna free6

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  • \$\begingroup\$ The traces are soooo tiny, make it wider! \$\endgroup\$
    – Jakub Rakus
    Commented Mar 30, 2017 at 21:04
  • \$\begingroup\$ Please elaborate! \$\endgroup\$
    – Thijs
    Commented Mar 30, 2017 at 21:27
  • \$\begingroup\$ 0.0983mil? It's a 2.5um! 2.5 micrometer! It's a thick of a hair! The rules of thumb: low voltage signal traces - 8 to 30mils, power lines - 50 or more mils, for ground - plane. \$\endgroup\$
    – Jakub Rakus
    Commented Mar 31, 2017 at 6:35
  • \$\begingroup\$ Thank you! This is all almost 10mil, I use the OSH Park KiCad template. I will update the power traces to 50mil and double check de trace width in KiCad. \$\endgroup\$
    – Thijs
    Commented Mar 31, 2017 at 6:49

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