Tennis Net Cord Accelerometer Detection for False Let Calls
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Solution Overview
Problem
Existing let detection systems in tennis are prone to false positives due to sensitivity to external factors like wind and changes in net tension, and fail to accurately detect slight contact with the net cord, especially when the net is not fully taut or straight.
Innovation Solution
A system using accelerometers attached to the net cord and strap to measure three-dimensional acceleration data, determining a rest state and transmitting an alert only if the average vertical acceleration exceeds a preset threshold, minimizing interference from horizontal movements and environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensors or piezoelectric sensors are used to detect net cord contact, then let detection capability is improved, but false positives increase due to sensitivity to wind and net tension changes
Solution Approach 1:
The patent changes the detection parameter from force/magnetic field to acceleration. By measuring acceleration of the net cord rather than force or magnetic field changes, the system becomes less sensitive to environmental factors like wind and net tension variations, thereby reducing false positives while maintaining let detection capability
Solution Approach 2:
The patent introduces accelerometers as intermediary sensors that indirectly measure net cord contact through acceleration patterns. Rather than directly measuring force or magnetic field changes, the accelerometers detect the motion response of the net cord, which serves as an intermediary indicator of ball contact while filtering out direct environmental interference
2Measurement precision
If sensors are mounted directly on the net cord, then detection sensitivity is improved, but detection accuracy decreases when the net is not fully taut or straight
Solution Approach 1:
The patent changes from measuring force or position directly to measuring acceleration patterns. Acceleration measurements are less dependent on the absolute tension or straightness of the net, allowing accurate detection even when the net sags or is not perfectly taut, as the acceleration signature of ball contact remains distinct from normal net variations
Solution Approach 2:
The patent moves from one-dimensional force or position measurement to three-dimensional acceleration measurement. By capturing acceleration in multiple dimensions, the system can distinguish between random net movements and genuine ball contact patterns, improving reliability when the net is not perfectly positioned or tensioned
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
Accurately detects net cord contact with reduced false positives, ensuring precise let calls even when the net is not perfectly straight or taut, improving the reliability of let detection in tennis.
Implementation Method 1
the at least one sensor includes at least one accelerometer, operable to generate three-dimensional (3D) acceleration data
Data Source
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AI summary
A let detection system includes a sensor including an accelerometer attached to a tennis net. The sensor is in wireless communication with an umpire device able to send a message to the sensor, wherein the message causes the sensor to calibrate and begin monitoring for a let. The sensor determines a three-dimensional (3D) vector representing the gravity acting on the sensor as a baseline. When the sensor detects vertical acceleration of the net relative to the baseline and the vertical motion is above a preset threshold, the sensor automatically transmits a let notification message to the umpire device.