Security systems and methods for protecting portable electronic devices from theft are provided. For example, a security system includes a sensor configured to be secured to a portable electronic device, and a monitoring component configured to wirelessly communicate with the sensor and to removably support the sensor thereon, wherein the monitoring component and the sensor are configured to communicate with one another to determine a proximity of the portable electronic device relative to the monitoring component, wherein the monitoring component and/or the sensor is configured to initiate a security signal when the proximity between the monitoring component and the sensor is not within a predetermined range. The sensor and the monitoring component are configured to communicate with one another for initially setting the predetermined range.