A wearable sensor apparatus, comprising: (a) a processor; (b) a plurality of sensors (320, 330, 340) operably coupled to the processor; (c) at least one haptic output (350, 360, 370) coupled to the processor; (d) programming in a non-transitory computer readable medium and executable on the processor for performing steps comprising: (i) designating a haptic output for possible sensor results of each sensor; (ii) acquiring sensor data from at least one sensor worn by a user; (iii) determining based on the acquired sensor data, if the user's presence is detected in a vehicle through detection by the wearable sensor apparatus of a predetermined vibration pattern, that the wearable sensor apparatus should adopt a vehicle mode; (iv) processing the acquired sensor data to match the acquired sensor data with the possible sensor results to which the designated haptic output is assigned; and (v) initiating the designated haptic output for matching sensor data, wherein the strength of the haptic output is increased when the wearable sensor apparatus is in the vehicle mode, and wherein, when the wearable sensor apparatus detects based on the processed sensor data that a driving direction of the user has strayed, the strength of the haptic output is set at a maximum level. (a) a processor; (b) a plurality of sensors (320, 330, 340) operably coupled to the processor; (c) at least one haptic output (350, 360, 370) coupled to the processor; (d) programming in a non-transitory computer readable medium and executable on the processor for performing steps comprising: (i) designating a haptic output for possible sensor results of each sensor; (ii) acquiring sensor data from at least one sensor worn by a user; (iii) determining based on the acquired sensor data, if the user's presence is detected in a vehicle through detection by the wearable sensor apparatus of a predetermined vibration pattern, that the wearable sensor apparatus should adopt a vehicle mode; (iv) processing the acquired sensor data to match the acquired sensor data with the possible sensor results to which the designated haptic output is assigned; and (v) initiating the designated haptic output for matching sensor data, wherein the strength of the haptic output is increased when the wearable sensor apparatus is in the vehicle mode, and wherein, when the wearable sensor apparatus detects based on the processed sensor data that a driving direction of the user has strayed, the strength of the haptic output is set at a maximum level. (i) designating a haptic output for possible sensor results of each sensor; (ii) acquiring sensor data from at least one sensor worn by a user; (iii) determining based on the acquired sensor data, if the user's presence is detected in a vehicle through detection by the wearable sensor apparatus of a predetermined vibration pattern, that the wearable sensor apparatus should adopt a vehicle mode; (iv) processing the acquired sensor data to match the acquired sensor data with the possible sensor results to which the designated haptic output is assigned; and (v) initiating the designated haptic output for matching sensor data, wherein the strength of the haptic output is increased when the wearable sensor apparatus is in the vehicle mode, and