Headset Accelerometers for Head Rotation Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing small listening devices, such as earbuds, face challenges in determining the direction and rotation of a user's head due to the large size, high cost, and high power consumption of gyroscopes, and the interference of magnetic fields with magnetometers, which limits their ability to provide angular motion information for applications like virtual reality and three-dimensional audio.
Innovation Solution
Incorporating accelerometers into each earpiece of a headset, which process acceleration information to determine the rotation and direction of the user's head, using a processor to differentiate between horizontal and non-horizontal motion, and integrating with compass or GPS systems for absolute direction sensing, allowing for the detection of head movements without the need for a mechanical connection between earpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gyroscope is used to track head rotation, then measurement precision is improved, but device size, cost, and power consumption increase
Solution Approach 1:
The system divides the head tracking function into multiple accelerometers distributed across different earpieces. Each accelerometer measures local acceleration, and the processor combines these segmented measurements to calculate overall head rotation, replacing the monolithic gyroscope approach
Solution Approach 2:
The patent replaces the mechanical gyroscope system with an electronic solution using accelerometers and signal processing. The accelerometers measure linear acceleration, and through computational algorithms, the system derives rotational information, eliminating the need for mechanical rotating components
2Measurement precision
If a magnetometer is used to determine absolute direction, then measurement precision is improved, but reliability deteriorates due to magnetic field interference
Solution Approach 1:
The patent introduces an intermediary approach by using the Earth's magnetic field as a reference framework. Instead of relying on a magnetometer that directly measures local magnetic fields (which are interfered with by the speaker), the system uses the stable, known magnetic north direction as a reference and calculates relative orientations through accelerometer data processing
Solution Approach 2:
The system creates a virtual copy of the magnetic reference frame through computational algorithms. By processing acceleration data and comparing it against the known Earth's magnetic field orientation, the system reconstructs absolute direction information without requiring direct magnetic field sensing in the presence of interference
3Device complexity
If accelerometers are used in each earpiece, then device complexity is reduced, but measurement precision may worsen due to lack of mechanical connection
Solution Approach 1:
The patent merges the data from multiple accelerometers through signal processing algorithms. The processor combines acceleration measurements from different earpieces, filters out noise, and integrates the data to calculate accurate head rotation and orientation, achieving precision comparable to or better than single-sensor systems
Solution Approach 2:
The system employs feedback mechanisms where the processor continuously monitors and adjusts the interpretation of accelerometer data based on the combined signals from multiple sensors. By comparing and cross-validating measurements from different earpieces, the system refines its head movement detection accuracy
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 the determination of head rotation and direction in a compact and cost-effective manner, enabling applications such as three-dimensional audio and navigation information, while maintaining low power consumption and avoiding interference from internal magnetic fields.
Implementation Method 1
An accelerometer associated with each earpiece of a headset provides information to determine the rotation and direction of a user's head
Data Source
AI summary
An audio headset system for a mobile phone or other audio player includes a pair of earpieces, each including a speaker in a housing and configured to provide audio output, the housing configured for positioning with respect to a user's ear to direct audio output to the ear; and a pair of accelerometers configured to provide acceleration information representative of acceleration of the respective earpieces, wherein together the acceleration information provided from both accelerometers is representative of angular motion in a horizontal plane of the head of a user. The angular motion may be used as inputs to carry out functions of the mobile phone, e.g., to provide sound adjustments for three dimensional stereophonic sound, to provide navigation information to a user, to play games, and so on. A method of determining rotation and/or direction of a user's head wearing a headset including an ear piece with an accelerometer at each ear, includes processing acceleration information from both accelerometers to determine angular motion of the user's head in a generally horizontal plane.