MEMS Push Button Control Using Dual IMU Attitude Sensing
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Solution Overview
Problem
Existing power tools using potentiometers for control are prone to wear, dust intrusion, and electrical shorts, leading to inconsistent performance over time, which affects user experience.
Innovation Solution
A smart push button device that converts linear motion into rotational motion using inertial measurement units (IMUs), where a first IMU rotates on a rotational member and a second IMU remains fixed, generating signals to control operational parameters like motor speed based on the attitude between the IMUs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a potentiometer is used to convert push button depression into an electrical control signal, then the control signal can be generated, but the potentiometer is subject to wear, dust intrusion and electrical shorts causing unreliable operation over time
Solution Approach 1:
The patent replaces the mechanical potentiometer system with a magnetic field-based sensing system. A magnet is attached to the push button, and a magnetic sensor (such as a Hall effect sensor or magnetoresistive sensor) detects the magnet's position and converts it into an electrical control signal. This eliminates mechanical contact and wear, providing wear-free operation and significantly extended service life while maintaining reliability.
Solution Approach 2:
The patent introduces a magnet as an intermediary between the push button and the electrical signaling system. The magnet moves with the push button but interacts with the magnetic sensor through a magnetic field rather than direct mechanical contact. This intermediary approach allows the push button's linear motion to be converted into positional information for the sensor without requiring the sensor itself to move or contact mechanical components, thereby improving reliability and durability.
2Reliability
If a potentiometer is used for control, then electrical control signals can be generated, but dust and metal filings get into the potentiometer causing electrical shorts
Solution Approach 1:
The patent replaces the mechanical potentiometer with a non-contact magnetic sensing system. The magnetic sensor detects the position of the magnet through magnetic field interaction without any physical opening or gap that would allow dust and metal filings to enter. This sealed, contactless approach eliminates the pathway for contaminants to reach sensitive electrical components, preventing electrical shorts and maintaining electrical stability.
Solution Approach 2:
The magnet serves as an intermediary that transmits positional information through a magnetic field, allowing the push button's movement to be sensed without creating an opening in the housing. The magnetic field penetrates the housing material without requiring gaps or openings, thereby blocking dust and contaminants from entering while still enabling accurate position detection for generating stable electrical control signals.
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
This solution provides a reliable and durable method for controlling power tool parameters, offering continuous feedback and improved responsiveness by translating linear motion into rotational displacement, thus enhancing user experience and tool performance.
Implementation Method 1
Two or more motion sensors, such as first and second inertial measurement units, are utilized to control one or more operational parameters or features of the tool based on operation of the smart push button
Implementation Method 2
The rotatable member is coupled to the linear member so that when the linear member moves, or is displaced, the rotatable member rotates proportional to the displacement of the linear member
Data Source
AI summary
A device for generating a control signal based on the linear movement of a linear member is provided. The device includes a linear member, a rotatable member, a first inertial measurement unit (IMU) coupled to the rotatable member and a second IMU having a fixed position. The device also includes a processing circuit which uses sensing signals from the IMUS to determine an attitude of the first IMU referenced to the second IMU and generate a control signal based on the attitude.