Wrist-Worn Temperature Sensor with Forehead Measurement via Accelerometer
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Solution Overview
Problem
Wrist-worn devices for measuring body temperature are inherently inaccurate when relying solely on wrist temperature readings, as they do not accurately represent the body's overall temperature.
Innovation Solution
A wrist-worn device equipped with a passive infrared sensor, an accelerometer, and a wireless communication module, which allows for forehead temperature measurement by detecting the lifting motion of the device and distinguishing between object and ambient temperatures, ensuring accurate body temperature readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive infrared sensor is placed in contact with the wrist for temperature measurement, then the device structure is simple, but the measurement accuracy is poor because wrist temperature does not represent body temperature
Solution Approach 1:
The patent uses the hand as an intermediary carrier to bring the passive infrared sensor close to the forehead. The hand holds the sensor in the required position during measurement, serving as a mediator between the sensor and the target (forehead) without requiring direct contact or complex positioning mechanisms.
Solution Approach 2:
The patent transitions from measuring temperature in the horizontal plane (wrist contact) to measuring in the vertical dimension by positioning the sensor at the forehead level. This spatial repositioning enables accurate forehead temperature measurement while maintaining the simplicity of the passive infrared sensor design.
2Measurement precision
If the measurement window is positioned to face the wrist for easy contact, then the device is easy to operate, but it cannot accurately measure forehead temperature
Solution Approach 1:
The patent makes the measurement window orientation dynamic rather than fixed. The hand can naturally move the device to different positions (wrist, forehead, temple) depending on the measurement requirement, allowing the same static device structure to adapt to different measurement locations and scenarios.
Solution Approach 2:
The device is designed to serve multiple measurement functions by positioning the passive infrared sensor at different locations (wrist, forehead, temple). This multi-functional capability allows the same device to measure body temperature accurately in various scenarios while maintaining ease of operation.
3Measurement precision
If multiple thermistor sensors are used to take many wrist temperature measurements, then statistical accuracy improves, but the device complexity and measurement time increase
Solution Approach 1:
The patent extracts the temperature measurement function from the wrist location and positions the passive infrared sensor directly at the forehead. This extraction eliminates the need for multiple wrist measurements and statistical processing, achieving accurate body temperature measurement with a single sensor in a single location.
Solution Approach 2:
The patent replaces the mechanical contact-based thermistor sensor system with a non-contact passive infrared sensor. This substitution eliminates the need for multiple measurements and complex signal processing, achieving accurate temperature measurement through direct infrared detection at the forehead.
4Measurement precision
If the device continuously monitors wrist temperature, then real-time monitoring is achieved, but measurement accuracy is compromised due to environmental factors affecting the wrist
Solution Approach 1:
The hand serves as a protective intermediary that shields the passive infrared sensor from direct exposure to environmental factors. By positioning the sensor at the forehead through hand movement, the system maintains measurement reliability while achieving real-time monitoring capability.
Solution Approach 2:
The patent extracts the temperature measurement function from the environmentally influenced wrist location and positions it at the forehead, which is less affected by external factors. This extraction improves measurement reliability while maintaining real-time monitoring capability through continuous hand movement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device provides accurate and reliable body temperature measurements by leveraging a passive infrared sensor and accelerometer to differentiate forehead temperature from ambient, enhancing measurement accuracy beyond traditional wrist-worn solutions.
Implementation Method 1
The housing contains a measurement window for a passive infrared sensor
Implementation Method 2
The housing also contains an accelerometer signal-connected to a microcontroller. The accelerometer is configured to continuously record the trajectory of the device
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The device (1) comprises a housing (2) with means for securing (3) it to the wrist (4) of a patient (15). Inside the housing (2) of this device (1) there is at least a microcontroller (7) and, signal-connected to it (4), a temperature transducer (8) and a wireless communication module (9). A passive infrared sensor is the temperature transducer (8). The housing (2) contains a measurement window (11) for the passive infrared sensor (8) and located on the housing's (2) surface that is not intended for contact with the wrist (4). The housing (2) also contains an accelerometer (10) signal-connected to a microcontroller (7).