Landmines are major problems, waste life and money. Much recent research acknowledges that the contact sensors have promising potential. In this work, a new idea of contact sensor for landmine detection is introduced. The sensor main principle is based on the concept of 2-DOF vibration absorber system (two springs and two masses), to detect the existence of an object (ex: landmine) in sand which is modeled as a 3 rd spring. The sand stiffness (the 3 rd spring stiffness k o ) can be acquired as function of the frequency vibration absorber mode ω Abs (the frequency at which the 2 nd mass has the lowest amplitude (mathematically proven: zero)). When the sand stiffness changed due to the presence of the landmine, the vibration absorber frequency ω Abs changes, and consequently the landmine can be detected. The mathematical derivation of the (ω Abs -k o ) relation is verified by simulations with Matlab and with finite element COMSOL Multi-physics. The system is succeeded to measure the sand stiffness up to 100kN/m. A physical prototype for the sensor is developed with sensitivity 16.85 (N/m)/Hz.