ESP8266 ESP-12 minimal stabilized circuit schematic and PCB * Breadboard friendly headers and Wemos D1 mini pin numbers * 0805 footprints for easy hand soldering * Designed for battery operation: Voltage regulator: Torex XC6220B331PR-G (8uA quiescent current, 1000mA max) VIN: max. 6V To enable self-wake from deep sleep, solder a 0 Ohm resistor over the WAKE pads You can use a 0 Ohm instead of a 470 Ohm resistor on TX, or solder a bridge. A cheap P-Channel MOSFET with low RDS(on) is used for reverse polarity protection, because unlike diodes it does not have a significant voltage drop. MOSFET: AO3401A by Alpha & Omega Semiconductor Inc. See this video about how the reverse polarity protection works: [https://www.youtube.com/watch?v=IrB-FPcv1Dc](https://www.youtube.com/watch?v=IrB-FPcv1Dc)