Could I do datalogging in Mindstorms EV3 Home edition? Apparently datalogging is an integrated part of the educational EV3 software. But I got the Home edition. Is there some module or thing I can use to get datalogging functionality in my Home edition?

Or do I need to build it myself?
Data logging is one of the things you are paying extra for when you purchase the Education software. Data logging is turned off in the Home version frimware and there is no means to configure data logging using the Home version software.

The firmware is open source, so technically, you could download it, figure out how to build it and turn on the data logging in the firmware, but then you would still need to reverse engineer a way to configure it.

If you don't need a very high sample rate (10-15 samples per second or less, probably), you could come up with something using an existing remote control library to log the data via USB or Bluetooth. For example, LeJOS and MonoBrick both have remote control libraries that would make it easy to write your own data logging program.

For a higher sample rate, you could write a program that runs on the brick using a 3rd party firmware/SD card image.