Acceleration sensor for touch display surface

A sensor unit configured to determine an acceleration of a touch display surface, the sensor unit comprising:

• a housing,
• a contact element movably mounted along a first axis and configured to come into contact with the touch display surface, wherein the contact element is moved along the first axis when coming into contact with the touch display surface,
• an acceleration sensor movably mounted in the housing at least along the first axis,
• a biasing element located on one side of the acceleration sensor and configured to bias the acceleration sensor in one of two directions along the first axis, wherein the contact element is movably mounted on the other side of the acceleration sensor opposite the biasing element and is coupled to the acceleration sensor to move the acceleration sensor against the bias of the biasing element in the other of the two directions along the first axis when contacting the touch display surface.