Single-Wire Wearable Sensor Buffering for High-Rate Sampling
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Solution Overview
Problem
Wearable sensor devices face limitations due to shared communication lines, which restrict data sampling rates, require unique identifiers that increase master device burden, and necessitate separate power lines, complicating integration and comfort.
Innovation Solution
A sensor device with a buffer to store time-series data, a single-wire bidirectional interface for communication and power, and a programmable identifier, allowing flexible 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 the number of physical lines, then the cost and complexity of the sensor system is reduced, but the data sampling rate decreases because each sensor device has limited time access to the communication lines
Solution Approach 1:
The sensor device stores sensor data in a buffer before it is read by the master device. This preliminary storage action allows the sensor to continuously acquire data at its full sampling rate without waiting for the master device to read it, thereby maintaining high sampling rates while using shared communication lines.
Solution Approach 2:
A buffer acts as an intermediary between the sensor module and the input-output interface. The buffer decouples the data acquisition process from the data transmission process, allowing the sensor to write data continuously while the master device reads data at its own pace, thus resolving the conflict between shared communication line constraints and sampling rate requirements.
2Reliability
If sensor devices have unique factory-programmed identifiers, then each sensor can be uniquely identified, but the burden on the master device increases as it must obtain and manage these identifiers before communication
Solution Approach 1:
The sensor device automatically generates a unique identifier based on its own characteristics (such as serial number or hardware features) and uses it for communication without requiring the master device to pre-obtain or pre-configure identifiers. This self-service approach reduces the setup burden on the master device while maintaining reliable unique identification.
3Reliability
If sensor devices require separate power lines to ensure consistent power supply, then power reliability is improved, but the number of physical conductors increases which is problematic for wearable articles
Solution Approach 1:
The bidirectional communication line serves multiple functions: it is used both for data transmission between the master device and sensor device, and for power transmission to the sensor device. This multi-functionality eliminates the need for separate dedicated power lines, reducing the total number of conductors while maintaining reliable power supply through the existing communication infrastructure.
Data Source
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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 non-volatile 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.