·        The WiFi firmware cannot be used directly, because the IIC pin definition is different, and you need to modify the source code and flash it in. The modified firmware is in the project attachment.

·        USB to serial chip uses CP2102, you need to install the corresponding driver.

·        The program is compiled with ARDUINO IDE, and some libraries need to be installed.

·        When downloading with arduino IDE, the development board needs to check NodeMCU 1.0 (ESP-12E Module).

·        Energy consumption problem: ESP8266 has three sleep modes. To use deep sleep, GPIO16 needs to be connected to the RESET pin; esp8266 uses a power supply to directly supply power. LDO can use the enabler to control the 3.3V switch.

·        Increase the power supply voltage detection circuit.

·        Power conversion: The system is powered by the USB power supply when the USB is connected, and the battery is powered when the USB is removed. Using the PMOS + Schottky diode solution, you can refer to the following circuit:

Peripherals can be added as needed, which will increase the difficulty of placement and routing accordingly.