Shot Detection Using Dual Accelerometer Segmentation
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Solution Overview
Problem
Existing shot counting devices for firearms are inaccurate and inefficient in power consumption, lacking robustness and precision in distinguishing real shot-events from false impacts, and do not effectively communicate with remote devices for online monitoring.
Innovation Solution
A shot detection and counter device utilizing a piezoelectric analogue accelerometer and a three-axis digital accelerometer, configured to distinguish real shot-events through pre-set configurations and wireless communication, with low power consumption and improved signal-to-noise ratio by angled sensor placement, and a Bluetooth low energy module for real-time data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single accelerometer sensor and basic wake-from-sleep circuit are used, then device complexity is reduced, but measurement precision and reliability of shot detection deteriorate
Solution Approach 1:
The shot detection function is segmented into two independent sensor systems: an analogue accelerometer for initial shot detection and wake-up triggering, and a digital three-axis accelerometer for precise waveform capture and analysis. This segmentation allows each sensor to be optimized for its specific function, improving overall detection accuracy while maintaining manageable device complexity
Solution Approach 2:
The patent combines two different types of accelerometers (analogue and digital) with complementary characteristics into a single integrated detection system. The analogue sensor provides fast wake-up response, while the digital sensor provides precise multi-axis waveform data, creating a synergistic system that achieves high measurement precision without excessive complexity
2Device complexity
If the accelerometer sensor is placed perpendicular to the impact axis, then the sensing mechanism is simplified, but signal-to-noise ratio deteriorates and false detections increase
Solution Approach 1:
The patent deliberately positions the analogue accelerometer sensor at a non-perpendicular (angled) orientation relative to the impact axis, creating an asymmetric sensor configuration. This asymmetric placement optimizes the signal-to-noise ratio by better aligning the sensor's sensitive axis with the actual acceleration vector during firing, while the microprocessor compensates for the angled orientation through coordinate transformation algorithms
3Measurement precision
If continuous monitoring is performed to ensure accurate shot detection, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The system implements periodic monitoring through event-triggered wake-up cycles rather than continuous monitoring. The analogue accelerometer periodically checks for shot events, wakes the microprocessor and digital accelerometer only when needed, then returns to sleep mode. This periodic action pattern maintains high detection accuracy while dramatically reducing average power consumption
Solution Approach 2:
The analogue accelerometer operates autonomously in low-power mode, automatically detecting shot events and triggering wake-up sequences without requiring the microprocessor to remain active. This self-service capability allows the system to maintain accurate shot detection while minimizing power consumption during idle periods
4Device complexity
If basic shot counting is implemented, then device complexity is minimized, but adaptability for different weapon types and monitoring applications is limited
Solution Approach 1:
The patent implements a universal shot counting platform that can adapt to different weapon types through configurable parameters stored in memory. The system can be programmed with weapon-specific characteristics (caliber, firing rate, recoil patterns) and can serve multiple functions including shot counting, waveform analysis, and remote monitoring. This multi-functionality is achieved through software configuration rather than hardware changes, maintaining low device complexity while maximizing adaptability
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
Achieves over 90% accuracy in shot counting with minimal power consumption, enabling real-time remote monitoring and shooter training through precise event differentiation and reduced false detections.
Implementation Method 1
an impact sensor adapted to detect a substantial impact event from a firearm, and to generate an analogue signal representing the impact event; the impact sensor is a piezo-electric sensor
Implementation Method 2
a three-axis digital accelerometer whose sampling initialisation is operatively triggered by a trigger signal received from the analogue accelerometer shock sensor to input a shot waveform to the microprocessor
Data Source
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AI summary
A device, system and method of detecting and counting shots fired from a weapon, the device including a microprocessor; an analogue accelerometer; a digital accelerometer whose sampling initialisation is operatively triggered by a trigger signal received from the analogue accelerometer to input a shot waveform to the microprocessor, the microprocessor being operable to: receive the trigger signal as a reference signal to the start of a weapon firing cycle, sample the shot waveform, calculate specific weighting coefficients from the shot waveform, compare the shot waveform with a pre-determined configuration of pre-sets to distinguish a real shot-event from a false shot-event, and produce a shot counter signal; and a wireless communications module for operatively transmitting the shot counter signal to a remote device being in operative communication with the shot counter device.