Abstract: A wrist joint-action detector adapted to be worn on or in the vicinity of the wrist region of a forearm detects wrist-joint actions of a user by using a proximity sensor in the detector to sense the separation between the proximity sensor and a body target in the wrist region. For example, a sensing plate of a capacitive proximity sensor is placed in the proximity of the wrist region of the forearm and the wrist region of the hand linked by the wrist joint to detect flexion, extension, abduction, or adduction of the wrist joint by sensing separation changes between the sensing plate and the wrist regions. Alternative proximity sensors, such as active infrared proximity sensors and imaging sensors, can also be used. The changes in separation between the proximity sensor and the body target can also be used for detecting handwashing or for controlling a computing device.

Abstract: An activity detector worn on or in the vicinity of the waist detects hip-joint actions of the user, by using a proximity sensor in the activity detector to sense the separation between the activity detector housing and a body target linked by the hip joint. For example, when the housing of an activity detector adjacent to the lower abdomen incorporates one or more sensing plates of a capacitive proximity sensor, flexion, extension, abduction, or adduction of the hip joint can be detected as the separation between the sensing plates and the lower abdomen changes. Besides the lower abdomen, alternative body targets include the thigh, buttocks, etc. Besides capacitive proximity sensors, alternative proximity sensors include active infrared proximity sensors, imaging sensors, etc. The activity detector can also incorporate an accelerometer to obtain additional movement and orientation data, which can be combined with the separation data to detect more complex activities.

Abstract: A wearable joint-action sensor detects actions of a joint that links a first body segment to a second body segment by using a proximity sensor worn on the first body segment to detect a separation between the proximity sensor and the first and/or second body segment. Actions of a hip joint can be detected by wearing the joint-action sensor on the waist, and actions of a finger joint can be detected by wearing the joint-action sensor on a finger. A waist-worn joint-action sensor incorporating a proximity sensor for detecting hip-joint actions and a triaxial accelerometer for detecting body actions can detect common physical activities, such as sitting, standing, dancing, push-ups, and sit-ups, that cannot be detected by a prior-art waist-worn or wrist-worn pedometer. A detected joint action can also be used for controlling a computing device, or for reminding a user of poor posture or of sitting for too long.

Abstract: Accelerometer-based detection for controlling audio-reporting watches, resulting in button-free operation. A wristwatch can use an accelerometer to detect the orientation and/or movement of a user's wrist and subsequently activate audio time reporting, without requiring the user to find and lush a small button. For example, a talking wristwatch can use this method to automatically report the time whenever a user moves or orients his or her wrist to a natural position for listening. A position such as that in close proximity to the ear can additionally facilitate private listening without disturbing others. Furthermore, the wristwatch can report time using personalized audio time components that the user has previously recorded, so that reporting is in a custom voice or language. In such applications, accelerometer-based control of audio-reporting watches offers significant advantages over conventional means of control, particularly in terms of ease of use and durability.

Abstract: Accelerometer-based detection for controlling audio-reporting watches, resulting in button-free operation. A wristwatch can use an accelerometer to detect the orientation and/or movement of a user's wrist and subsequently activate audio time reporting, without requiring the user to find and lush a small button. For example, a talking wristwatch can use this method to automatically report the time whenever a user moves or orients his or her wrist to a natural position for listening. A position such as that in close proximity to the ear can additionally facilitate private listening without disturbing others. Furthermore, the wristwatch can report time using personalized audio time components that the user has previously recorded, so that reporting is in a custom voice or language. In such applications, accelerometer-based control of audio-reporting watches offers significant advantages over conventional means of control, particularly in terms of ease of use and durability.

Abstract: Accelerometer-based orientation and/or movement detection for controlling wearable audio recorders, such as wrist-worn audio recorders, resulting in button-free operation of the audio recorders. Operating a button-free wearable audio recorder does not rely on conventional switches that are often small, difficult to operate, and not very reliable. A wrist-worn audio recorder can use an accelerometer to detect the natural orientation and/or movement of a user's wrist and subsequently activate a corresponding audio-recorder function, for instance recording or playback, without requiring the user to remember to activate the audio-recorder function. In addition, a wearable audio recorder with a vibration mechanism can use this method to remind a user of an undesirable repeated movement, such as restless leg movement.

Abstract: A system for synchronizing data after they are collected and stored locally in sensor units in a distributed sensor system, so that wired or wireless communication is not required during a data-collection session. Each sensor unit has a local clock providing local-clock times before and after a data-collection session, and a data processor uses its local clock or a sensor unit's local clock as the reference to compute each sensor unit's time-scaling factor, which is the ratio of the elapsed reference local-clock time and the elapsed local-clock time. The data processor uses the time-scaling factor to convert each sensor unit's local-clock data-sampling times to the reference local-clock data-sampling times, and the data processor subsequently interpolates sensor data to approximate simultaneous sensor-data values at desired reference local-clock times. A physical-activity monitoring system can use this synchronization method to reduce the size, power consumption, and cost of the sensor units.

Abstract: Accelerometer-based orientation and/or movement detection for controlling wearable devices, such as wrist-worn audio recorders and wristwatches. A wrist-worn audio recorder can use an accelerometer to detect the orientation and/or movement of a user's wrist and subsequently activate a corresponding audio-recorder function, for instance recording or playback. A wearable device with a vibration mechanism can use this method to remind a user of an undesirable movement such as restless leg movement. Likewise, a talking wristwatch can use this method to activate audio reporting of time when a user moves or orients his or her wrist in close proximity to his or her ear. In such applications, and many others, accelerometer-based control of the wearable device offers significant advantages over conventional means of control, particularly in terms of ease of use and durability.