Capacitive Sensor for User Contact Detection in Analyte Test Meters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analyte test meters face accuracy issues due to contact between the user and the electrochemical test strip during measurement, which can lead to incorrect analyte detection in fluid samples.
Innovation Solution
An analyte test meter equipped with a capacitive sensor that detects contact between the user and the test strip by measuring changes in capacitance levels before and after fluid sample dosing, using a drive signal to identify and differentiate between proper dosing and user contact, thereby preventing interference in analyte measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a user applies a fluid sample to the test strip, then the analyte measurement can be performed, but user contact with the test strip may reduce measurement accuracy
Solution Approach 1:
The system performs preliminary actions by detecting user contact with the test strip before the analyte measurement is completed. The capacitive sensor continuously monitors for changes in capacitance that indicate user contact, and the system can interrupt or flag the measurement before contact interference degrades accuracy, preventing the harmful effect rather than correcting it afterward.
Solution Approach 2:
The system implements feedback by using the capacitive sensor to continuously monitor contact conditions during the measurement process. When user contact is detected through capacitance changes, the system provides feedback to the measurement process by generating an alert or interrupting the measurement, allowing the user to remove their finger and retry, thereby maintaining measurement precision.
2Reliability
If the capacitive sensor continuously monitors for contact, then user contact can be detected, but additional circuitry and processing are required
Solution Approach 1:
The capacitive sensor serves multiple functions: it detects user contact with the test strip, monitors sample application status, and can potentially detect other operational states. By making the sensor multi-functional, the patent reduces the need for separate dedicated contact detection hardware, thereby improving reliability without proportionally increasing device complexity.
Solution Approach 2:
The capacitive sensor utilizes the test strip's existing electrical properties and the user's body capacitance as the detection mechanism. The system leverages natural physical phenomena (capacitance changes when conductive material like skin contacts the strip) rather than requiring active sensing elements on the test strip itself, allowing the test strip to effectively participate in its own monitoring.
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 effectively reduces interference from user contact, enhancing the accuracy of analyte detection by ensuring proper conditions for measurement and preventing measurement errors.
Implementation Method 1
measure a first response to the drive signal from the capacitive sensor corresponding to a first level of capacitance in the capacitive sensor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An analyte test meter that detects contact between a user and an electrochemical test strip includes a test strip port, a capacitive sensor positioned proximate to the test strip port, and a controller connected to the test strip port and the capacitive sensor. The controller is configured to identify insertion of the electrochemical test strip into the test strip port, apply a drive signal to the capacitive sensor, measure a first response to the drive signal from the capacitive sensor, identify dosing of a fluid sample on the electrochemical test strip, apply the drive signal to the capacitive sensor after the dosing, measure a second response to the drive signal from the capacitive sensor, and detect contact between a body of a user and at least one electrode in the electrochemical test strip in response to a difference between the first and second responses exceeding a predetermined threshold.