Data logger - storing data with a microcontroller

In your projects you are often confronted with measured values of all kinds, no matter if soil moisture, temperature or air pressure - the collected data provide information about how our environment changes. For this reason it is important not only to see the data in a snapshot (e.g. in the serial monitor of the Arduino IDE), but to store it and to evaluate it.
We succeed in doing this by using modules that have been developed especially for storing data. These modules, also called data loggers, are plugged onto a microcontroller and are directly ready for use.
Often you will find a button cell and an inlet for SD cards on these boards. The button cells are part of an RTC module installed on the data logger, which time stamps the collected data. The SD card is used to store the collected data, usually in a .csv file. The resulting file with the data is the cornerstone of the data evaluation.