TIDUEX1A December   2020  – March 2021

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TMP117 – High-accuracy, low-power, digital temperature sensor
      2. 2.3.2 System Design Theory
        1. 2.3.2.1 System Accuracy
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware
    2. 3.2 Software
      1. 3.2.1 SysConfig
      2. 3.2.2 Graphical User Interface (GUI)
        1. 3.2.2.1 Launching and Running the Software
        2. 3.2.2.2 Using the GUI
          1. 3.2.2.2.1 Home Tab
          2. 3.2.2.2.2 Data Capture Tab
          3. 3.2.2.2.3 EVM Setup Tab
          4. 3.2.2.2.4 Configuration Tab
          5. 3.2.2.2.5 Register Tab
          6. 3.2.2.2.6 Collateral Tab
    3. 3.3 Testing and Results
      1. 3.3.1 Test Setup
        1. 3.3.1.1 System Accuracy
      2. 3.3.2 Test Results
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
      1. 4.2.1 PCB Layout Recommendations
      2. 4.2.2 Software Files
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  10. 5Revision History

1 System Description

With the increasing demand for health data collection, the need for accurate body temperature monitoring has become very desirable. Tracking body temperature trends has been used to indicate potential illnesses, disruptions in sleep cycles, athletes’ recovery status, and other health trends.

While oral and rectal measurements are common and accurate methods of measuring body temperature, they are extremely intrusive. A less intrusive method to measure accurate body temperature is through the ear via the tympanic membrane. Measuring body temperature through the ear has been a common practice for decades and integrating high-accurate temperature sensors into hearable devices, such as earbuds or hearing aids, can be used to do the same.

Hearable devices are in close proximity to the tympanic membrane and can create a seal in the ear canal making a practical environment to get consistent temperature measurements relative to one's body temperature. Headphones, earbuds, and hearing aids are designed to be very comfortable so they can be worn for hours and sometimes days continuously. This allows for continuous tracking of an individual's temperature and can establish trends of normal temperatures and any deviations from normal which could indicate potential infections, hormonal shifts, or diseases.

The TMP117 high-accuracy, low-power, digital temperature sensor can send 16-bit digital temperature data through I²C to a microcontroller. Since the surrounding electronic system and ambient temperature can create different offsets in the temperature reading, a second TMP117 can be used to adjust for thermal gradients between the body temperature and these environmental temperatures.

This hearable design integrates two TMP117 temperature sensors; one for measuring the in-ear temperature (main sensor), and another for system and ambient temperature sensing (secondary sensor). The reference design is on an extremely low profile thin-film flex cable making it easily integrated into a hearable device and features breakout headers and speaker soldering pads to support different MCUs, power supplies, and speakers.