On Thursday, the U.S. Patent and Trademark Office officially published a series of three patent applications from Apple relating to Apple watch and Apple Watch Ultra. The patents cover multi-functional environmental sensors, submersion detection, underwater depth and more.

For the first patent, Apple's patent background notes that electronic devices such as laptop computers, cellular telephone, and other equipment are sometimes provided with environmental sensors, such as ambient light sensors, image sensors, and microphones. However, it may be difficult to incorporate some environmental sensors into an electronic device where space is at a premium, such as Apple Watch.

Electronic Devices With Multi-Function Environmental Sensors

An electronic device such as Apple watch is carried by users as they conduct their daily activities such as commuting or exercising. In some situations, it may be desirable for the user to know the air speed, ambient temperature, solar radiation, presence of water in the device's surroundings, and/or the heat flux across a housing of the device.

To make one or more of these measurements, a layer of metal may be coupled to the device housing, or a strand of metal may be incorporated into a mesh that covers one or more components, such as a speaker or microphone, inside of the electronic device. The layer or strand of metal may be heated to a known temperature, and the decay of the temperature of the metal back to an equilibrium temperature may indicate the air speed.

To measure ambient temperature, a reference resistor may be used, and the decay of the temperature of the metal may be compared to the decay of the reference resistor.

Alternatively or additionally, the layer of metal may include multiple metals, or multiple strands of different metals that may be incorporated into the mesh, and Seebeck Voltages across junctions between the different metals may indicate the heat flux across the device housing.

If desired, the layer or strands of metal may be used to determine solar radiation and/or the presence of water (if other unknowns can be determined, such as by modifying the layer of metal to have portions with different insulation). In this way, the layers or strands of metal may be used as an anemometer, thermometer, bolometer, water sensor, and/or heat flux sensor.

While the main focus of the invention relates to Apple Watch, Apple doesn't want to limit the invention's limitation and notes that the invention could also relate to an iPhone, HomePod, smart glasses, Vision Pro, AirPods or other accessories.

For full details, review Apple's patent application 20240085223. 

Submersion Detection, Underwater Depth and Low-Latency Temperature Estimation using Apple watch

Apple notes in their patent background that users participating in recreational underwater activities, such as scuba diving, snorkeling, underwater pool swims and shallow free diving, can benefit from various underwater sensing, including current depth, maximum depth, time under water and water temperature. Such sensing typically requires specific underwater sensing devices, such as wrist-worn dive computers and/or bulky mechanical gauges. Such devices provide little or no benefit to the user for land-based activities. Accordingly, there is a need for a single wearable device that can provide environment sensing for underwater and land-based recreational activities.

Apple's invention covers embodiments relating to submersion detection and underwater depth and low-latency temperature estimation. The invention relates directly to Apple Watch and Apple's patent application does a deep dive into the details that engineers and developers may appreciate.  

(Click on image to greatly Enlarge)

Apple notes that in some embodiments, a method comprises: determining, with at least one processor, a first set of vertical accelerations obtained from an inertial sensor of a wearable device; determining, with the at least one processor, a second set of vertical accelerations obtained from pressure data; determining, with the at least one processor, a first feature associated with a correlation between the first and second sets of vertical accelerations; and determining, with the at least one processor, whether the wearable device is submerged or not submerged in water based on a machine learning model applied to the first feature.

In some embodiments, the method further comprises determining, with the at least one processor; a second feature associated with a slope of a line fitted to a plot of the first set of accelerations and the second set of accelerations; and determining, with the at least one processor, that the wearable device is submerged or not submerged in the water based on a machine learning model applied to the first feature and the second feature.

In some embodiments, the method further comprises determining, with the at least one processor, a second feature associated with a touch screen gesture; and determining, with the at least one processor, whether the wearable device is submerged or not submerged in the water based on a machine learning model applied to the first feature and the second feature.

In some embodiments, responsive to determining that the wearable device is submerged in water, the method further comprises estimating, with the at least one processor, a depth of the wearable device based on a measured pressure and a stored measured air pressure computed and stored by the wearable device prior to the wearable device being submerged in the water.

In some embodiments, determining whether the wearable device is submerged or not submerged in the water further comprises comparing the estimated depth with a minimum depth threshold.

In some embodiments, a method comprises: determining, with at least one processor, a water submersion state of a wearable device; and responsive to the submersion state being submerged, computing, with the at least one processor, a forward estimate of the water temperature based on a measured ambient water temperature, a temperature error lookup table, and a rate of change of the ambient water temperature.

In some embodiments, the ambient air pressure at the surface is measured each time the first set of vertical accelerations are above a minimum threshold and a range of measured pressure change is less than or equal to a specified pressure threshold.nd-based recreational activities (I couldn't find a definition for "threshold.nd").

For finer details, review Apple's patent application 20240085185.

Active Aggressor Detection in Pressure Sensor Port

A third Apple Watch patent application 20240085258 published this week titled "Active Aggressor Detection in Pressure Sensor Port" could be reviewed here. The patent abstract states the following:

"Aspects of the subject technology relate to an apparatus having a housing, including a port exposed to an environment. The apparatus includes a pressure sensor disposed within the housing to measure a pressure of the environment. The pressure sensor includes a membrane to facilitate detection of a presence of an aggressor by using dynamic response analysis."