Pillow Speaker Interlock Circuit for Multi-Channel Nurse Call Signaling
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Solution Overview
Problem
Traditional nurse call pillow speaker systems are limited by single communication channels and lack an interlock system capable of handling multiple communication signals, which is critical in modern nurse call systems that require more complex signaling.
Innovation Solution
An interlock system with a microcontroller and optocouplers to selectively connect and disconnect terminals in a signaling loop, allowing for multiple communication channels and providing feedback on connection states through monitoring circuits, including sense resistors and Hall effect sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a simple push button switch is used for nurse call signaling, then the device complexity is reduced and ease of manufacture is improved, but the system can only support single communication channel and lacks adaptability for multiple communication signals
Solution Approach 1:
The patent implements a universal communication interface that can handle multiple communication protocols (analog, digital, bidirectional) through a single standardized connector. The pillow speaker system is designed to accommodate various communication signals through one interface, eliminating the need for separate connectors for each communication type and enabling multi-functionality without proportionally increasing complexity.
Solution Approach 2:
The communication interface is segmented into distinct functional layers: physical connector layer, signal conditioning layer, and protocol processing layer. This segmentation allows the system to support multiple communication channels by adding or modifying protocol processing while maintaining the same physical interface, thereby improving adaptability without linearly increasing overall device complexity.
2Measurement precision
If traditional interlock circuit is used to detect pillow speaker connection, then the circuit simplicity is maintained, but the system cannot provide accurate detection of connection states and may generate false alarms
Solution Approach 1:
The patent implements a feedback mechanism where the microcontroller actively monitors the interlock circuit state and can respond by generating appropriate alarm conditions or communication signals. This feedback loop enables accurate detection of connection states by continuously monitoring the circuit and comparing it against expected states, thereby improving measurement precision while the microcontroller manages the complexity of the monitoring logic.
Solution Approach 2:
The patent introduces an intermediary monitoring circuit between the simple interlock switch and the alarm system. This intermediary layer processes the raw switch state signal, filters out false conditions, and provides cleaned connection status information to the microcontroller, thereby improving detection accuracy while isolating the complexity within a dedicated monitoring module.
3Reliability
If galvanic isolation is implemented between control circuit and connection circuit, then the reliability of nurse call signaling is improved and false alarms are reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs an optocoupler as an intermediary device to provide galvanic isolation between the control circuit and the connection circuit. The optocoupler transfers control signals across the isolation barrier using light, thereby achieving reliable galvanic isolation while using a single standardized component that simplifies manufacturing compared to custom isolation solutions. This approach improves signaling reliability while maintaining ease of manufacture through component standardization.
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 support for multiple communication channels and accurate detection of connection states, enhancing the reliability of nurse call signaling and reducing false alarms by using isolated circuits and feedback mechanisms.
Implementation Method 1
The isolation circuit may include a first optocoupler having a phototransistor to selectively connect the first terminal with the second terminal based on illumination from an LED
Implementation Method 2
The isolation circuit may include a first optocoupler having a phototransistor to selectively connect the first terminal with the second terminal based on illumination from an LED
Implementation Method 3
The monitoring circuit may include a coil connected between the first terminal and the second terminal. The monitoring circuit may include a Hall effect sensor. The Hall effect sensor may be configured to detect a magnetic field generated by a current flowing through the coil
Data Source
AI summary
An interlock system for signaling a nurse call patient station is disclosed. The interlock system may include a first terminal and a second terminal. The first and second terminals may be configured to be connected to corresponding terminals of a signaling loop of a nurse call patient station. The interlock system may further include a connection circuit. The connection circuit may be configured to electrically connect the first terminal to the second terminal. The interlock system may also include a control circuit in communication with, but isolated from, the connection circuit. The control circuit may include a microcontroller. The control circuit may be isolated from the connection circuit by an isolation circuit. The control circuit may be configured to operate the connection circuit to connect or disconnect the first terminal from the second terminal.