Abstract: A temperature sensing system includes absolute temperature sensor(s) and/or thermopiles that form concentric geometries and are uniform in height. In some examples, the temperature sensing system can determine internal body temperature and/or ambient temperature based at least on a thermal gradient associated with the inner thermopile, a thermal gradient associated with the outer thermopile, a lateral temperature difference between the inner and the outer thermopiles, and an absolute temperature. In some examples, the temperature sensing system can determine the internal body temperature and/or ambient temperature using at least four absolute temperature sensors forming a concentric structure.

Abstract: Robust estimation of temperatures inside and outside a device can be achieved using one or more absolute temperature sensors optionally in conjunction with thermopile heat flux sensors. Thermopile temperature sensing systems can measure a temperature gradient across two locations within the device, to estimate absolute temperature at locations that are impractical to measure using absolute temperature sensors. Using heat flux models associated with the device, the thermopile temperature sensing system can be used to estimate temperature associated with objects that contact an outer surface of the device, such as a user's skin temperature. Additionally, the thermopile temperature sensing system can be used to estimate ambient air temperature. Within a device, temperature measurements from the thermopile temperature sensors can be used to compensate sensor measurements, such as when the accuracy or reliability of a sensor varies with temperature.

Abstract: Disclosed herein are capacitive sensors, and methods for their operation, that determine the presence of a user by detecting input forces and/or pressures. Capacitive sensors may be in the form of a flexible capacitive sensing mat. An electronic device incorporating a flexible capacitive sensing mat may include spacer fabric disposed between conductive layers. The spacer fabric may have a first thickness and may be configured to compress to at least a second thickness when a threshold pressure is applied to the layered sensor and revert to the first thickness when the threshold pressure is no longer applied to the flexible mat. A capacitive sense circuit electrically coupled to the second conductive layer and configured to generate a presence detection signal when the spacer fabric layer compresses to the second thickness may additionally be provided.

Abstract: Embodiments are directed to a blood pressure measurement device including a cuff that is operative to wrap around a limb of a user, a bladder coupled to the cuff and operative to compress the limb of the user when inflated, and a piezoelectric sensor coupled to the cuff and operative to detect blood flow through the limb of the user and output a signal indicative of the blood flow. The blood pressure measurement device can also include a processor coupled with the piezoelectric sensor that is operative to filter the signal to isolate sounds corresponding to changes in the blood flow through the limb due to inflation of the bladder, correlate the isolated sounds with a pressure inside the bladder, and determine a blood pressure of the user at least partially based on correlating the isolated sounds with the pressure.

Abstract: A sensor system includes a sensor stack, a differential amplifier, an analog-to-digital converter, and a processor. The sensor stack includes a piezoelectric material having a first side opposing a second side, a first electrode connected to the first side, and a second electrode connected to the second side. The differential amplifier is coupled to the first and second electrodes and is configured to generate a differential output indicative of vibrations sensed by the piezoelectric material. The analog-to-differential converter is configured to digitize the differential output. The processor is configured to identify a type of biological vibration included in the digitized differential output.

Abstract: A sleep monitor includes a layered sensor that includes at least one substrate layer that includes multiple laterally adjacent substrates. The substrate layer may be formed by interdigitating fingers of a first sheet with fingers of a second sheet. Combining multiple substrates in a single layer of a layered sensor may allow multiple materials and/or sensing mechanisms to be combined together in a single layer.