Orthogonal Pressure Sensor Array for Motion Detection
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Solution Overview
Problem
Existing motion detection systems rely heavily on accelerometers and gyroscopes, which may not effectively utilize pressure sensors for motion detection, especially in applications where pressure changes are prevalent, such as in varying altitudes or environmental activities.
Innovation Solution
A system and method utilizing multiple pressure sensors arranged orthogonally to detect pressure changes and differentiate between motion and ambient pressure changes, employing filters and signal processing to determine the direction and magnitude of motion by comparing signals from these sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If accelerometers and gyroscopes are used for motion detection, then motion detection capability is achieved, but system cost increases and pressure sensor functionality is underutilized
Solution Approach 1:
The patent enables pressure sensors, originally designed for atmospheric or environmental pressure sensing, to perform dual functionality by detecting both pressure changes and motion. This is achieved through signal processing techniques that distinguish between pressure-induced membrane deflection and motion-induced deflection, allowing existing pressure sensors to serve multiple purposes and reduce system cost.
Solution Approach 2:
The patent replaces the need for separate mechanical motion detection devices (accelerometers and gyroscopes) with a signal processing approach that uses pressure sensor output. By analyzing the characteristics of pressure sensor signals and applying appropriate filtering and comparison techniques, the system substitutes dedicated motion detection hardware with a software-based solution that leverages existing pressure sensing capability.
2Device complexity
If pressure sensors are used for motion detection, then system cost is reduced, but distinguishing between motion and ambient pressure changes becomes difficult
Solution Approach 1:
The patent employs multiple pressure sensors arranged in specific configurations (e.g., orthogonal arrangements) to segment the detection task. By comparing signals from multiple sensors, the system can distinguish between ambient pressure changes (which affect all sensors similarly) and motion (which creates differential pressure patterns). This segmentation approach transforms a difficult single-sensor problem into a more manageable multi-sensor comparison problem.
Solution Approach 2:
The patent implements signal processing feedback mechanisms where the output from multiple pressure sensors is continuously compared and analyzed. The system uses the collective information from all sensors to feedback-correct the interpretation of individual sensor signals, enabling reliable distinction between pressure changes and motion despite the inherent difficulty of the measurement task.
3Measurement precision
If multiple pressure sensors are arranged orthogonally to detect motion, then motion detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent utilizes orthogonal arrangements of pressure sensors to capture pressure variations in multiple spatial dimensions. By positioning sensors at right angles to each other, the system can detect motion vectors in three-dimensional space, transforming a scalar pressure measurement into a vector-based motion detection capability. This dimensional approach improves measurement precision by providing directional information about motion.
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
Enables accurate motion detection using pressure sensors, reducing system costs and leveraging existing microphone technology for dual functionality in devices like smartphones and tablets, effectively distinguishing between motion and ambient pressure changes.
Implementation Method 1
A common sensor that includes a transducer is a pressure sensor that converts pressure differences and/or pressure changes to electrical signals
Implementation Method 2
Pressure sensors may also be implemented as capacitive MEMS devices that include a sealed volume and a deflectable membrane. A pressure difference between the sealed volume and an external volume, such as the ambient environment in some cases, causes the membrane to deflect. Generally, the deflection of the membrane causes a change in distance between the membrane and a sensing electrode, thereby changing the capacitance.
Data Source
AI summary
According to an embodiment, a method of sensing motion includes receiving a first signal from a first pressure sensor and a second signal from a second pressure sensor, comparing the first signal and the second signal, and characterizing a motion based on the comparing.