Attachment for a cleaning device with moisture detection and method for moisture detection

A method of operating a cleaning device, comprising:

• assessing a content of liquid cleaning agent in a cleaning medium;
• detecting a strength of vibration in the cleaning device;
• and
• evaluating a change in the strength of the vibration, wherein the cleaning device comprises:
• a housing,
• a cleaning agent dosing unit comprising an electrically operated pump, wherein the cleaning medium is configured to receive the cleaning agent from the electrically operated pump,
• a cleaning medium carrier configured to receive the cleaning medium on an underside of the cleaning medium carrier,
• a drive configured to drive the cleaning medium carrier,
• at least one vibration sensor arranged in the housing, the at least one vibration sensor configured to detect the strength of a vibration, and
• a controller configured to assess the content of liquid cleaning agent in the cleaning medium based on a variation in the strength of vibration detected by the at least one vibration sensor, wherein the variation is caused by changes in a total oscillating mass of the cleaning medium due to the content of liquid cleaning agent in the cleaning medium.