Phyphox allows you to create your own experiments using a visual experiment editor, which will generate a simple file, that defines your experiment including data analysis. You can then copy this file to your phone or share it with colleagues or students, so they can perform the experiment, which you have designed.
In fact, even the experiments included in phyphox are defined in the same format and you can simply load and modify them to your needs.
However, one word of warning: The editor is very mighty and hence quite complex. The following introduction video should be a good starting point if you want to use it:
The editor itself can be found here.