Cash Drawer Status Detection Using XOR Logic Circuit
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Solution Overview
Problem
The existing point of sales systems cannot accurately determine if a cash drawer is stolen or moved, leading to a cash-loss risk as they fail to detect the interruption of the signal connection between the cash drawer and the control host.
Innovation Solution
A detecting device with an operation logic circuit and a switch element is integrated into the control host, utilizing an XOR or XNOR gate to determine the status of the cash drawer by comparing voltage levels, treating a disconnected cash drawer as an open status to inform the user of its actual state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a micro switch is used to detect cash drawer status, then the detection is simple and reliable when the drawer is closed, but the system cannot detect when the drawer is stolen or moved because the signal connection is interrupted
Solution Approach 1:
The patent introduces an intermediary detection mechanism (the second detecting means) that mediates between the micro switch signal and the control unit. This intermediary layer can detect both the micro switch state and the connection wire integrity, allowing the system to distinguish between a closed drawer and a stolen/moved drawer. The intermediary translates the connection status into meaningful status information for the control unit.
Solution Approach 2:
The patent implements a feedback mechanism where the second detecting means continuously monitors the connection wire and provides feedback to the control unit. When the connection is interrupted (drawer stolen or moved), the feedback signal changes state, enabling the control unit to recognize the abnormal status. This feedback loop ensures real-time detection and response to drawer status changes.
2Device complexity
If the system treats a disconnected cash drawer as a closed status, then the circuit remains simple, but the system displays incorrect information leading to cash-loss risk
Solution Approach 1:
The patent segments the detection function into two independent parts: the first detecting means (micro switch) that detects drawer closure, and the second detecting means (connection detector) that detects wire integrity. This segmentation allows each detector to perform its specific function independently, with the control unit integrating both signals to determine the overall status. This modular approach maintains circuit simplicity while improving detection accuracy.
3Loss of information
If no additional detection means is added, then the device complexity remains low, but the system cannot distinguish between a normally closed drawer and a stolen drawer
Solution Approach 1:
The second detecting means serves multiple functions: it detects connection wire integrity, determines whether the drawer is stolen or moved, and provides status information to the control unit. By designing this single component to perform multiple detection tasks, the patent avoids adding excessive complexity while comprehensively solving the information loss problem.
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 allows the control host to accurately display the real status of the cash drawer, reducing the risk of cash loss by confirming the opened status even when the cash drawer is stolen or moved, thereby enhancing monitoring capabilities.
Implementation Method 1
the electromagnetic switch 23, a micro switch 24, and a drawer 22 that can be opened or closed for storing the cash. In the drawer 22, there is an induction driving circuit 221 that can automatically open the drawer 22 from the housing 21 when the electromagnetic switch 23 is enabled.
Data Source
AI summary
A detecting device for a cash drawer is used for detecting a status of the cash drawer. The detecting device includes an operation logic circuit and a switch element. The operation logic circuit has a first input terminal, a second input terminal and an output terminal. The first input terminal and the second input terminal are respectively coupled with a micro switch. The first input terminal and the second input terminal are respectively inputted with a high level voltage. When the first input terminal and the second input terminal have the same logic voltage levels, the operation logic circuit outputs a first logic level to the output terminal. When the first input terminal and the second input terminal have different logic voltage levels, the operation logic circuit outputs a second logic level to the output terminal. The switch element is coupled between an electromagnetic switch and the first input terminal.