A logging system is a system that can write data and information.
Data and information could include sensor data, system events, and error messages. All data and information is usually stored in external storage such as SD cards, microSD cards, or on a hard disk.
In general, a logging system can be described as in the following figure. An MCU with sensor devices attached can sense things such as temperature and humidity. This sensor data can also be stored in external storage:
Figure 4-1: A general model for a logging system
In this chapter, we explore how to work with external storage from an ESP32 board. We will build a simple logging system to store sensor data in external storage.