Summary

The first experiment gave a good insight of Nipkows idea.
https://www.thingiverse.com/thing:2909460
Now, we install a lens over the window that focusses the light on a phototransistor. Nipkow used a celenium cell in his time. We use a BPW40 which is sensitive for the entire visible spectrum. The signal will be around 10mV.
The lens is standard and you will find one on the internet. They are used in VR-viewers. An oscilloscope shows the signal which can be transmitted to the other side of the world. The signal is very week, so you will need proper amplification. Move the sensor-cylinder untill you have maximum signal, which means the focussing is O.K. To eliminate the influence of ambient light, the back side of the sensor should be shielded (e.g. a drop of black paint).
All parts are printed in one run.The lens is kept in place by a clamp.The pinhole disk from the first experiment is used here as well.