Vacuum cleaning machines

A vacuum machine comprising:

• a housing for receiving vacuumed matter and at least two removably attachable accessories comprising a first accessory and a second accessory, at least the first or second accessory comprising a filter;
• sensing means for detecting the first and second accessories;
• a control circuit communicatively coupled with the sensing means;
• wherein the sensing means is activated in dependence of a proximity of the filter to the sensing means;
• the sensing means being arranged to generate a first signal, a second signal and a third signal, and to output the first, second and third signal to the control circuit, the first signal representative of the presence of the first accessory, the second signal representative of the presence of both the first and second accessories, and the third signal representative of the absence of accessories, the control circuit being arranged to prevent operation of the vacuum machine when the first signal is received and to allow operation of the vacuum machine when the second or third signal is received, wherein the second signal is representative of the dry vacuuming state and the third claim signal is representative of the wet vacuuming state.