“In this tutorial we will build an ultra-low power temperature node to work with our ESP32 Hub system.
We will be using two of the most popular temperature sensors, the DS18B20 and the DHT22 Temperature and Humidity sensor.
The node is based on a modified Arduino Pro Mini 3.3V (Clone) and is powered by a single rechargeable 18650 Lithium Ion Battery. The node works by periodically transmitting the temperature back to the hub, then going into a deep sleep for a period of time. Depending on how regularly the sensor transmits, the battery has the potential of lasting over a year on a single charge.
As the Arduino Pro Mini does not have a USB connector on it, we will also need an FTDI Serial Programmer.
Supplies:FTDI USB Serial Programmer 18650 Battery and Holder (and a charger for the battery) Assembled HC-12 Module DS18B20 and/or DHT22 Temperature sensor 4.7K Resistor (For the DS18B20) Female Dupont Header socket”