Sweat-Activated Switch Circuitry for Wearable Fluid Monitoring
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Solution Overview
Problem
Current sweat sensing technologies face challenges such as variable results, lack of correlation between sweat and blood values, and inefficient power management in wearable devices, leading to frequent recharging and increased device size and weight due to high power consumption.
Innovation Solution
A switch circuitry that controls power supply to fluid monitoring units based on the detection of sweat, activating the unit only when fluid is present, using sensors to generate a detection signal that activates a wake-up signal for the power switch, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the fluid monitoring unit operates continuously to enable prolonged monitoring, then the monitoring duration is extended, but the power consumption increases significantly
Solution Approach 1:
The system implements periodic monitoring by placing the fluid monitoring unit in sleep mode during intervals when no fluid is detected, and activating it only when fluid presence is detected. This periodic operation pattern extends monitoring duration over time while significantly reducing average power consumption compared to continuous operation.
2Duration of action of moving object
If the battery size is increased to extend operating time, then the monitoring duration is extended, but the device footprint and weight increase
Solution Approach 1:
By implementing periodic operation with sleep modes, the system reduces average power consumption to levels that can be sustained by smaller batteries. This allows extended operating time to be achieved without proportionally increasing battery size, thereby maintaining acceptable device weight and footprint.
3Reliability
If the fluid monitoring unit is activated continuously, then monitoring reliability is maintained, but power is wasted when no fluid is present
Solution Approach 1:
The system uses the detected fluid presence signal itself to control the activation of the monitoring unit. When fluid is detected, the system automatically activates; when no fluid is present, it enters sleep mode. This self-service mechanism ensures monitoring reliability is maintained whenever fluid is available while eliminating energy waste during dry periods.
4Reliability
If the sensor continuously monitors for fluid to enable reliable detection, then the detection reliability is improved, but the power consumption increases
Solution Approach 1:
The sensor operates in a periodic manner, remaining active to detect fluid presence signals and then enabling the main monitoring unit only when detection occurs. This approach maintains detection reliability by keeping the sensor ready to sense fluid while avoiding continuous operation of the power-intensive monitoring electronics, thereby reducing overall power consumption.
Data Source
AI summary
According to an aspect, there is provided switch circuitry (1) for controlling power supplied to a fluid monitoring unit (4). The switch circuitry (1) comprises: a sensor (2) configured to detect fluid derived from the skin of a user and to generate a detection signal in response to detection of fluid; and a controller (3) configured to receive the detection signal, to generate a wake-up signal in accordance with the detection signal, and to supply the wake-up signal to a switch (6) controlling the power supply to the fluid monitoring unit (4) so as to activate the switch (6) and wake the fluid monitoring unit (4), wherein, optionally, the fluid is sweat. According to another aspect, there is provided method of controlling power to a fluid monitoring unit.