Abstract: A user-wearable devices includes an on-body detector that uses one or more sensors of the device to detect whether or not the user-wearable device is being worn by a user. When the user-wearable device is detected as being worn by a user it is operated in a first mode, and when the user-wearable device is detected as not being worn by a user it is operated in a second mode that consumes less power than the first mode. Operating the user-wearable device in the first mode can include enabling wireless communication between the user-wearable device and a base station. Operating the user-wearable device in the second mode can include disabling wireless communication between the user-wearable device and a base station. Operating the user-wearable device in the second mode can also include disabling sensors of the user-wearable device and/or placing sensors of the user-wearable device in a low power mode.

Abstract: A user-wearable devices includes an on-body detector that uses one or more sensors of the device to detect whether or not the user-wearable device is being worn by a user. When the user-wearable device is detected as being worn by a user it is operated in a first mode, and when the user-wearable device is detected as not being worn by a user it is operated in a second mode that consumes less power than the first mode. Operating the user-wearable device in the first mode can include enabling wireless communication between the user-wearable device and a base station. Operating the user-wearable device in the second mode can include disabling wireless communication between the user-wearable device and a base station. Operating the user-wearable device in the second mode can also include disabling sensors of the user-wearable device and/or placing sensors of the user-wearable device in a low power mode.

Abstract: A processor for an activity monitor for a user has a reduced power mode in which it does not process data samples from an accelerometer. A wake up circuit or logic evaluates an output from the accelerometer and determines whether the output exceeds a threshold, indicating a threshold amount of activity of the user. If the threshold is exceeded, the wake up circuit or logic causes the processor to enter an active mode. The processor evaluates samples of the accelerometer in an evaluation period and decides whether to continue in the active mode or return to the reduced power mode. If the user is deemed to be sufficiently active, the processor continues in the active mode. In another aspect, the threshold can be set based on an activity level of the user before the reduced power mode or sensor data such as ambient light level or skin temperature.

Abstract: An activity monitor such as a wrist-worn device has an accelerometer which continuously detects motion of the user. The activity monitor also has an on-demand heart rate monitor which is activated by the user touching it from time to time. A calorie expenditure based on the motion of the user can be modified based on a heart rate measurement. Further, a determination can be made as to whether the user has made repetitive motions for a period of time. If the repetitive motions are detected, a calorie expenditure based on the heart rate is determined and compared to the calorie expenditure based on the user motion, and the higher value prevails. A situation is avoided in which the activity monitor underestimates the calories expended, such as when the user is exercising strenuously but the accelerometer indicates relatively little motion, e.g., during strength training.

Abstract: An activity monitor such as a wrist-worn device has an accelerometer which continuously detects motion of the user. The activity monitor also has an on-demand heart rate monitor which is activated by the user touching it from time to time. A calorie expenditure based on the motion of the user can be modified based on a heart rate measurement. Further, a determination can be made as to whether the user has made repetitive motions for a period of time. If the repetitive motions are detected, a calorie expenditure based on the heart rate is determined and compared to the calorie expenditure based on the user motion, and the higher value prevails. A situation is avoided in which the activity monitor underestimates the calories expended, such as when the user is exercising strenuously but the accelerometer indicates relatively little motion, e.g., during strength training.

Abstract: A processor for an activity monitor for a user has a reduced power mode in which it does not process data samples from an accelerometer. A wake up circuit or logic evaluates an output from the accelerometer and determines whether the output exceeds a threshold, indicating a threshold amount of activity of the user. If the threshold is exceeded, the wake up circuit or logic causes the processor to enter an active mode. The processor evaluates samples of the accelerometer in an evaluation period and decides whether to continue in the active mode or return to the reduced power mode. If the user is deemed to be sufficiently active, the processor continues in the active mode. In another aspect, the threshold can be set based on an activity level of the user before the reduced power mode or sensor data such as ambient light level or skin temperature.