Piezo Sensor Channel Sharing for Haptic Feedback Circuits
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Solution Overview
Problem
The existing piezoelectric switch circuits require a large number of microcontroller channels to manage both sensor input and haptic signaling, leading to complex circuit designs as each piezoelectric sensor element necessitates separate channels for reading and producing haptic signals.
Innovation Solution
A piezoelectric sensor system that utilizes a microcontroller with a multiplexer to share piezo channels for both reading sensor inputs and generating haptic signals, allowing a single channel to be used for both functions through a boost converter and switch configuration, thereby reducing the number of required microcontroller channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate microcontroller channels are used for each piezoelectric sensor element to manage both sensor input and haptic signaling, then the sensor input reading and haptic signal production can be independently controlled, but the number of required microcontroller channels increases rapidly leading to complex circuit design
Solution Approach 1:
The patent combines the sensor input reading function and haptic signal control function into a single shared piezo channel. The same piezo channel that reads sensor input is also used to control the switch for generating haptic feedback, eliminating the need for separate channels and reducing circuit complexity.
Solution Approach 2:
The piezo channel is designed to serve multiple functions: it acts as both a sensor input channel for reading touch signals and as a control channel for switching the boost converter to generate haptic feedback. This multi-functionality reduces the total number of channels required.
2Device complexity
If a single piezo channel is shared for both sensor input reading and haptic signal control, then the number of microcontroller channels is reduced simplifying circuit design, but the channel must be time-interleaved between two functions
Solution Approach 1:
The system uses periodic time-interleaved operation where the piezo channel alternates between sensor reading mode and haptic control mode. The microcontroller switches the channel between these two functions in a time-multiplexed manner, allowing the single channel to efficiently handle both tasks without conflict.
3Adaptability or versatility
If multiple piezoelectric sensor elements are used to produce haptic signaling, then more haptic feedback can be provided, but the number of microcontroller channels required increases rapidly
Solution Approach 1:
Each piezoelectric sensor element uses its corresponding piezo channel for both sensor reading and haptic control. This merging of functions for each element allows multiple haptic outputs without proportionally increasing the number of microcontroller channels, as each channel handles dual responsibilities.
Solution Approach 2:
The system design allows each piezo channel to universally serve both sensing and actuation functions across multiple piezoelectric elements. This universal dual-function approach enables scalable haptic feedback without linearly increasing channel requirements.
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 configuration simplifies the circuit design by enabling the same piezo channel to be used for both collecting sensor inputs and producing haptic feedback, reducing the overall microcontroller resource needs and allowing for more efficient use of channels.
Implementation Method 1
detect a signal resulting from bending of at least one piezoelectric sensor element being part of the circuit
Implementation Method 2
produce a haptic signal by a voltage generated by a boost converter
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
To simplify circuit design, a piezoelectric sensor (2') is proposed. The piezoelectric sensor (2') comprises a microcontroller (26), a plurality of piezoelectric sensor elements (20) of which at least two are i) useable for producing a haptic signal by a voltage (HV) generated by a boost converter (1101) connected to each piezoelectric sensor element (20) via a respective switch (1105), and ii) connected to a piezo channel (PZF1; PFZ2; PZF3) of the microcontroller (26). The piezoelectric sensor (2') further comprises a multiplexer (80) for individually controlling each of the switches (1105) for which a signal is present at a digital selection line connected to the respective piezo channel (PZF1; PZF2; PZF3), if an enable a signal (DRVP) from increase voltage pin (53) is present. The microcontroller (26) is configured: i) to use each of the piezo channels (PZF1; PFZ2; PZF3) as a sensor channel for reading sensor input from the respective piezoelectric sensor element (20); and ii) in response to detecting a sensor input in at least one of the piezo channels (PZF1; PZF2; PZF3), a) to set the enable signal (DRVP) at the increase voltage pin (53) and/or the signals (HVEN) at the enable signal pin (54) (DRVP, HVEN), and iib) to set a signal to at least one piezo channel (PZF1; PZF2; PZF3) in which the sensor input was detected, for producing a haptic signal with the respective piezoelectric sensor element (20), such that the signal will be set in a time-interleaved manner with respect to the sensor input.