Amazon patents wearable that estimates glucose from skin CO2

1. A system comprising: a wearable device comprising: a housing having: an internal volume; a first side; a second side; a first opening in the first side, wherein the first opening faces a body of a user when the wearable device is worn and enables passage of carbon dioxide from the body of the user into the internal volume; and a second opening in the second side, wherein the second opening enables passage of carbon dioxide from the internal volume to an ambient environment external to the housing; a first carbon dioxide sensor within the housing, wherein the first carbon dioxide sensor determines first sensor data indicative of a first quantity of carbon dioxide within the internal volume; and a valve in the second opening; and one or more memories storing computer-executable instructions; and one or more hardware processors to execute the computer-executable instructions to: at a first time, open the valve to enable carbon dioxide within the internal volume to pass through the second opening; at a second time after the first time, close the valve to prevent passage of carbon dioxide through the second opening; at a third time after the second time, determine that a threshold length of time associated with accumulation of carbon dioxide in the internal volume has elapsed; determine the first quantity of carbon dioxide based on the first sensor data in response to the elapsing of the threshold length of time, wherein the first quantity of carbon dioxide is indicative of carbon dioxide emitted from skin of the user through the first opening in the housing; determine a metabolized glucose value based on the first quantity of carbon dioxide and lookup data, wherein the lookup data associates the first quantity of carbon dioxide with the metabolized glucose value; and generate output based on the metabolized glucose value.