To set perfect belt tension we will make it vibrate and tune it to a certain frequency, just like a guitar. To do that we will use a smartphone application.

Download and install the Pano Tuner application (developed by Kaleloft LLC) on your smartphone.

Android Google Play link.

Apple Store link.

Turn off the printer (if your hotend is higher than 50°C, let the hotend cool down first until the hotend fan stops spinning)

Launch the Pano Tuner app and place your smartphone on the heated bed. Make sure there is no noise in the room that could disrupt the measurement (like a ceiling fan).