Single-Wire Sensor Device With Buffer Memory For Wearables
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Solution Overview
Problem
Sensor devices connected via shared communication lines face limitations in data sampling rate, require separate power lines, and have fixed, factory-programmed identifiers, which increase complexity and error risk in wearable articles.
Innovation Solution
A sensor device with a buffer to store time-series data, a single-wire input-output interface for data and power transmission, and programmable non-volatile memory to change identifiers, allowing efficient data transmission and power management without additional lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sensor devices use shared communication lines to reduce physical conductors, then device complexity and number of physical connections are reduced, but data sampling rate decreases due to limited access time
Solution Approach 1:
The sensor device stores sensor data in a buffer memory before it is requested by the master device. This preliminary storage action allows the sensor to capture data continuously at its full sampling rate without waiting for communication line access, thereby resolving the contradiction between using shared communication lines and maintaining high data sampling rates
Solution Approach 2:
A buffer memory is introduced as an intermediary component between the sensor and the master device. The buffer acts as a temporary storage mediator that decouples the data acquisition process from the data transmission process, allowing the sensor to maintain high sampling rates while communicating over shared lines at lower rates
2Ease of manufacture
If sensor devices have fixed factory-programmed identifiers, then manufacturing is simplified, but error risk increases due to use of incorrect identifiers and burden on master device
Solution Approach 1:
The identifier in the sensor device is made dynamically changeable through a programmable interface, allowing it to be modified after manufacturing. This dynamic property enables the master device to assign unique identifiers and eliminates errors from incorrect fixed identifiers, while manufacturing remains simple with default identifiers
Solution Approach 2:
The identifier parameter is changed from a fixed factory-programmed value to a programmable value that can be modified through communication with the master device. This parameter change allows flexible identifier assignment and reduces communication errors while maintaining ease of manufacture with default values
3Reliability
If separate power lines are used to ensure consistent power supply, then power supply reliability is improved, but number of physical conductors increases
Solution Approach 1:
The power supply function is merged with the existing shared communication line by implementing power transmission over the same bidirectional wire used for data communication. This combining of functions eliminates the need for separate power lines while maintaining reliable power supply through controlled power transmission during communication idle periods
Solution Approach 2:
The bidirectional communication line is given multi-functionality by enabling it to carry both data signals and power signals. This universal use of the communication line for both data and power transmission reduces the total number of physical conductors required while ensuring consistent power supply to the sensor device
Data Source
AI summary
The sensor device (10) comprises a sensor module (101) and an input-output interface (105) arranged to send and receive data over a bidirectional line (11). A buffer (103) is arranged to store time-series sensor data. A programmable and erasable nonvolatile memory (109) receives and stores an identifier for the sensor device (10). The sensor module (101) generates an inference using the sensor data. The sensor device (10) is arranged to switch between sending, over the bidirectional line (11), data sensed by the sensor module (101) and the generated inference. The sensor device (10) is a single-wire sensor device. The input-output interface (105) is a single-wire input-output interface. The sensor module (101) is a motion, electropotential, electroimpedance, chemical, or optical sensor module. The sensor device (10) is provided in a system comprising a master device. The sensor device (10) or system is incorporated into a wearable article.