A system for determining structural characteristics of an object, comprising: a device having a housing with an open end and a longitudinal axis; an energy application tool mounted inside said housing for applying energy to said object, said energy application tool having a resting and an active position; a drive mechanism supported inside said housing and coupled to said energy application tool, said drive mechanism adapted for repeatedly moving said energy application tool from said resting to said active position; a sleeve portion protruding from said open end of said housing for a distance, said sleeve portion having an object contacting portion at its free open end and is adapted for contacting at least a portion of said object with at least a portion of said object contacting portion of its open end; an internal on/off-activation mechanism for the device comprising: a sensor positioned inside said housing for monitoring a contact force between said object contacting portion of said sleeve portion and said object when at least a portion of said object contacting portion of said sleeve portion contacts at least a portion of the object, said sensor not being directly physically coupled to said energy application tool; and a movable force transfer sleeve component disposed inside said housing at the front of the housing for transferring said contact force from said sleeve portion to one end of said sensor, said transfer sleeve component is adapted for translational movement; wherein said sensor activates said drive mechanism to automatically start a measurement by moving the energy application tool when said exerted contact force is in a predetermined range without the need for an external switch. a device having a housing with an open end and a longitudinal axis; an energy application tool mounted inside said housing for applying energy to said object, said energy application tool having a resting and an active position; a drive mechanism supported inside said housing and coupled to said energy application tool, said drive mechanism adapted for repeatedly moving said energy application tool from said resting to said active position; a sleeve portion protruding from said open end of said housing for a distance, said sleeve portion having an object contacting portion at its free open end and is adapted for contacting at least a portion of said object with at least a portion of said object contacting portion of its open end; an internal on/off-activation mechanism for the device comprising: a sensor positioned inside said housing for monitoring a contact force between said object contacting portion of said sleeve portion and said object when at least a portion of said object contacting portion of said sleeve portion contacts at least a portion of the object, said sensor not being directly physically coupled to said energy application tool; and a movable force transfer sleeve component disposed inside said housing at the front of the housing for transferring said contact force from said sleeve portion to one end of said sensor, said transfer sleeve component is adapted for translational movement; wherein said sensor activates said drive mechanism to automatically start a measurement by moving the energy application tool when said exerted contact force is in a predetermined range without the need for an external switch. a sensor positioned inside said housing for monitoring a contact force between said object contacting portion of said sleeve portion and said object when at least a portion of said object contacting portion of said sleeve portion contacts at least a portion of the object, said sensor not being directly physically coupled to said energy application tool; and a movable force transfer sleeve component disposed inside said housing at the front of the housing for transferring said contact force from said sleeve portion to one end of said sensor, said transfer sleeve component is adapted for translational movement; wherein said sensor activates said drive mechanism to automatically start a measurement by moving the energy application tool when said exerted contact force is in a predetermined range without the need for an external switch.