1. A system configured to reduce power consumption of a sensor according to analysis of content, comprising: a content emotional response analyzer (content ERA) configured to: receive a first segment of content, analyze the first segment, and output a first indication indicating that a first value related to an emotional response to the first segment does not reach a first predetermined threshold; and a hardware-based controller configured to select, based on the first indication, a first mode of operation for a sensor for measuring affective response of a user to the first segment; wherein the content ERA is further configured to: receive a second segment of content, analyze the second segment, and output a second indication indicating that a second value related to an emotional response to the second segment reaches a second predetermined threshold; and the hardware-based controller is further configured to select, based on the second indication, a second mode of operation for the sensor for measuring affective response of the user to the second segment; wherein the sensor is configured to consume at least 50% less power while operating at the first mode of operation compared to the power it is configured to consume while operating at the second mode of operation.