Many outdoor temperature sensors are battery-powered and use a proprietary protocol for data transmission. The project described here uses an ESP8266-based board for sending temperature data directly to a home automation system and is powered directly from mains.
The three basic components are:
NodeMCU is a development board for the ESP8266, a low-cost solution for getting your projects connected to WiFi. It can be powered and programmed directly from USB. No additional material required!
The job of this power supply is to provide stable 3.3V when connected to mains AC. There are many options but this product on Tindie looked like the perfect fit