I have a S5D9 IOT board. It is very compact. I want to share my tutorial with the community on how to add ADC capability to the board. I think that it is very useful if the sensor only has an analog output.
In this tutorial, I show 4 examples that covers both r_iic and r_sci_i2c drivers with and without framework. Here is my blog link with source code available.
There are other blogs from me such as adding a distance sensor, a temperature sensor, and a small OLED display that may be useful for your next small project. Feel free to explore them.