A vibration sensor (1000, 1100) comprising 1) a pressure detecting arrangement adapted to detect generated pressure variations, and provide an output signal in response to the detected pressure variations, wherein the pressure detecting arrangement comprises a MEMS microphone comprising a housing having a PCB (1002, 1103), wherein an acoustical opening (1010, 1108) is provided in the PCB (1002, 1103), and wherein the MEMS microphone further comprises a MEMS cartridge (1006, 1110) comprising a membrane (1008, 1111) and a front chamber (1011, 1113), and a back chamber (1009, 1112) within which back chamber (1109, 1112) a signal processor (1007, 1114) is provided, 2) a pressure generating arrangement adapted to generate pressure variations in response to vibrations thereof, wherein the pressure generating arrangement comprises a housing (1003, 1102), a suspension member (1005, 1106) and a moveable mass (1004, 1107) secured to the suspension member (1005, 1106) wherein the pressure generating arrangement is secured to the PCB (1002, 1103) and is arranged on top of the MEMS microphone, and wherein a volume (1013, 1115) exists between the suspension member (1005, 1106) and an upper side of the PCB (1002, 1103), and wherein the acoustical opening (1010, 1108) in the PCB (1002, 1103) is acoustically connected to the volume (1013, 1115), and wherein the suspension member (1005, 1106) and the moveable mass (1004, 1107) comprise respective acoustical openings, and wherein the volume (1013, 1115) is smaller than 5 mm 3, such as smaller than 2 mm 3, such as smaller than 1 mm 3, such as smaller than 0.75 mm 3, such as smaller than 0.5 mm 3, such as smaller than 0.25 mm 3, such as smaller than 0.1 mm 3. 1) a pressure detecting arrangement adapted to detect generated pressure variations, and provide an output signal in response to the detected pressure variations, wherein the pressure detecting arrangement comprises a MEMS microphone comprising a housing having a PCB (1002, 1103), wherein an acoustical opening (1010, 1108) is provided in the PCB (1002, 1103), and wherein the MEMS microphone further comprises a MEMS cartridge (1006, 1110) comprising a membrane (1008, 1111) and a front chamber (1011, 1113), and a back chamber (1009, 1112) within which back chamber (1109, 1112) a signal processor (1007, 1114) is provided, 2) a pressure generating arrangement adapted to generate pressure variations in response to vibrations thereof, wherein the pressure generating arrangement comprises a housing (1003, 1102), a suspension member (1005, 1106) and a moveable mass (1004, 1107) secured to the suspension member (1005, 1106) wherein the pressure generating arrangement is secured to the PCB (1002, 1103) and is arranged on top of the MEMS microphone, and wherein a volume (1013, 1115) exists between the suspension member (1005, 1106) and an upper side of the PCB (1002, 1103), and wherein the acoustical opening (1010, 1108) in the PCB (1002, 1103) is acoustically connected to the volume (1013, 1115), and wherein the suspension member (1005, 1106) and the moveable mass (1004, 1107) comprise respective acoustical openings, and wherein the volume (1013, 1115) is smaller than 5 mm 3, such as smaller than 2 mm 3, such as smaller than 1 mm 3, such as smaller than 0.75 mm 3, such as smaller than 0.5 mm 3, such as smaller than 0.25 mm 3, such as smaller than 0.1 mm 3.