Capacitive Sensor Donning Detection for Head-Mountable Power Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Head-mountable computing devices face challenges in conserving battery power, as they continuously operate in a high-power state even when not in use, leading to reduced battery life.
Innovation Solution
Incorporating capacitive sensors to detect when the device is donned or doffed, allowing the device to switch between power states, with reduced power consumption when not in use, by comparing the rate of change of capacitance with a threshold and adjusting operations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the head-mountable computing device continuously operates in a high-power state, then the device is always ready for use and provides continuous functionality, but the battery power is depleted faster and battery life is reduced
Solution Approach 1:
The device dynamically adjusts its operational state based on real-time sensor inputs. The system transitions between active and low-power states by monitoring capacitive sensor data that detects whether the device is being worn. This dynamic state adjustment allows the device to maintain readiness when needed while conserving battery life when not in use, directly resolving the contradiction between continuous availability and battery duration.
2Duration of action of moving object
If the device switches to a lower power state when not in use, then battery life is extended and energy is conserved, but the device cannot respond immediately when needed
Solution Approach 1:
The capacitive sensors continuously monitor for the presence of a user before the device needs to become active. By detecting changes in capacitance that indicate the device is being donned, the system prepares for activation in advance. This preliminary detection mechanism ensures that when the user puts on the device, the system can quickly transition from low-power to active state, maintaining fast response time while still benefiting from extended battery life during periods of non-use.
3Use of energy by moving object
If capacitive sensors are used to detect donning and doffing events, then power consumption is reduced by switching states appropriately, but the device complexity increases due to additional sensing components
Solution Approach 1:
The capacitive sensors serve multiple functions within the device. Beyond detecting donning and doffing events for power state management, capacitive sensors can also detect touch inputs, proximity of objects, and other user interactions. This multi-functionality allows the same hardware components to reduce power consumption through intelligent state switching while simultaneously providing additional input capabilities, thereby offsetting the added complexity with enhanced functionality and justifying the inclusion of sensor systems.
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 approach effectively conserves power by switching the device to a lower power state when not in use, thereby extending battery life and optimizing energy usage.
Implementation Method 1
capacitive sensors to detect when the device is donned or doffed
Data Source
AI summary
Methods and devices for determining whether a head-mountable computing device is donned or doffed are disclosed. In one embodiment, a method is disclosed that includes receiving from at least one capacitive sensor data indicating a rate of change of capacitance, making a comparison of the rate of change of capacitance to a threshold rate of change of capacitance and, based on the comparison, determining whether the head-mountable computing device is donned or doffed. The method further includes, if the head-mountable computing device is donned, causing the head-mountable computing device to operate in a first state, and if the head-mountable computing device is doffed, causing the head-mountable computing device to operate in a second state, where the head-mountable computing device consumes less power in the second state than in the first state.