Configuration

Purpose

The aim of the implemented configuration is to write settings like wifi name and password to a separate configuration file instead of hard coding them in the source code. This gives the user the advantage of being able to change settings without having to change or re-flash the source code.

Actually the following settings are implemented into the config.

• wifi ssid
• wifi password
• aws url
• aws port
• mqtt subsribe topic
• mqtt publish topic
• device id
• device position
• logger level
• logger output level

Implementation

Create Config file

To create the configuration file the python script genreate_config.py is used. This script must be called from a command line, and the settings are then entered from the command line as well. Then a file called config_file.json is created atomatically and stored in a directory with the name data.

The created configuration file is of the type json. This format is commonly used in IoT applications for data exchange. In a json file the data is stored as text in a ordered way. This makes it easy to create, edit and read these files.

Upload Config

On the ESP device the configuration file is stored in the SPIFFS file system together with the certificates for the ssl connection.

To upload the configuration we suggest to use PlatformIO but you are also free to use a other option like the Ardunio-IDE.

The upload process is described here.

EspConfig Class

The Esp_Config class is used on the ESP to read the configuration file from SPIFFS and to make the its contents available through getFkt() functions.

The class is implemented as singelton. Therefore the normal way to get an object of the class is to call getInstance() and then a pointer to the object will be returned.

To read the config file you have to call only once the readConfig() function of the EspConfig object.

This class uses the class Esp_Spiffs to read the SPIFFS and the library ArduinoJson.h to parse the json file.