A wearable device (150, 150a, 150b), comprising: apparatus for securing the wearable device to a user's body; a sensor system including one or more biometric sensors, the one or more biometric sensors including an ultrasonic sensor capable of obtaining image data corresponding to a portion of the user's body on which the wearable device is being worn, the sensor system being capable of obtaining first biometric data from a user's body, the first biometric data including image data obtained by the ultrasonic sensor, the image data including at least one type of image data selected from the group consisting of: hair follicle image data, pore image data, skin papilla image data and sub-dermal blood vessel image data; a wireless interface system; a substance delivery system; and a control system capable of: receiving the first biometric data from the sensor system; determining first biometric authentication information based on the first biometric data, wherein the first biometric authentication information includes a representation of the first biometric data; providing, via the wireless interface system, the first biometric authentication information to a second device (500, 500a, 500b); receiving, via the wireless interface system, a control signal from the second device, wherein the control signal is an authentication indication indicating whether the user has been authenticated; and controlling the substance delivery system according to the control signal. apparatus for securing the wearable device to a user's body; a sensor system including one or more biometric sensors, the one or more biometric sensors including an ultrasonic sensor capable of obtaining image data corresponding to a portion of the user's body on which the wearable device is being worn, the sensor system being capable of obtaining first biometric data from a user's body, the first biometric data including image data obtained by the ultrasonic sensor, the image data including at least one type of image data selected from the group consisting of: hair follicle image data, pore image data, skin papilla image data and sub-dermal blood vessel image data; a wireless interface system; a substance delivery system; and a control system capable of: receiving the first biometric data from the sensor system; determining first biometric authentication information based on the first biometric data, wherein the first biometric authentication information includes a representation of the first biometric data; providing, via the wireless interface system, the first biometric authentication information to a second device (500, 500a, 500b); receiving, via the wireless interface system, a control signal from the second device, wherein the control signal is an authentication indication indicating whether the user has been authenticated; and controlling the substance delivery system according to the control signal. receiving the first biometric data from the sensor system; determining first biometric authentication information based on the first biometric data, wherein the first biometric authentication information includes a representation of the first biometric data; providing, via the wireless interface system, the first biometric authentication information to a second device (500, 500a, 500b); receiving, via the wireless interface system, a control signal from the second device, wherein the control signal is an authentication indication indicating whether the user has been authenticated; and controlling the substance delivery system according to the control signal.