Wearable Devices 2019
- 1. < Slide 1 > Building a Better Wearable Device – What You Need to Know Walt Maclay President, Voler Systems Product Development
- 2. < Slide 2 > Agenda • Common physiological measurements • Battery limitations • Things that impact power • Data security
- 3. < Slide 3 > Innovation examples FitBit Activity Monitor Elder monitor Bluetooth hearing aid Eye care Sleep analysis
- 4. < Slide 4 > Common physiological measurements
- 5. < Slide 5 > Body Temperature • Few good locations to measure core temperature • Axilla (under arm) or forehead are best locations • Not convenient for a wearable device • Extremeties (eg wrist) have variable temperature • Algorithms can partially adjust over time • Good contact is important – heat flow causes errors
- 6. < Slide 6 > Motion • The most studied and used parameter • Step counts • Gait analysis (illness) • Types of motion (walking, standing, sitting) • Dead reckoning (9-axis motion) • Works on wrist, ankle, torso, etc. • Different algorithms at different locations
- 7. < Slide 7 > Heart Rate • Measured by • ECG electrodes – two are sufficient • Pulse oximeter sensing – transmissive • Transmitted works on finger and ear • Pulse oximeter – reflected • Works more places on body • Pressure sensing of the pulse in the wrist • Heart rate can be measured on many parts of the body
- 8. < Slide 8 > Blood Oxygen • Oxygen saturation in blood • Measured by pulse oximeter (infra-red) technology • Measure loss through body of 2 IR wavelengths • Separates changes in blood from other changes • Measure pulse at the same time • Transmissive or reflective measurement • Reflective for more places on body • Transmissive for better accuracy
- 9. < Slide 9 > ECG / EMG / EEG • Measure of electrical and muscle activity • ECG measurement points have to be rather far apart • At least one and a half inches – larger devices needed • More leads is better (up to 12 for standard ECG) • EMG requires accurate placement (millimeters) • Measure the wrong muscle • EEG must use electrodes on the head
- 10. < Slide 10 > Respiration Rate • Number of breaths per minute • Few good locations to measure • Movement of chest • Chest strap • Not convenient for a wearable device except shirt • Thoracic Impedance eliminates chest strap • Device can be small • Difficult on wrist
- 11. < Slide 11 > Blood Pressure • Measure of systolic and diastolic pressure • Accurate measurement requires pressure cuff that is compressed and released • Cuff on arm or wrist • Pulse Transit Time – measure at wrist or elsewhere • Currently not accurate enough for medical diagnosis
- 12. < Slide 12 > Blood Sugar (Glucose) • Measure of glucose level in blood sample • Widely used • Becoming a wearable • with microneedles or implanted • Frequent calibration required • Attempts to not use finger tip – less accurate • Not accurate on wrist • Closed loop system replaces the pancreas • Measure and control glucose with a pump
- 13. < Slide 13 > Agenda • Common physiological measurements • Battery limitations • Things that impact power • Data security
- 14. < Slide 14 > Battery Limitations • Slow pace of improvement If improved like semiconductors: Size of a pin head, could power your car, cost 1 cent • Must always work around limitations w Long time between charging vs small size
- 15. < Slide 15 > When Will Battery Technology Improve? • Chemical energy storage is approaching the limit of its efficiency • Nuclear energy is out of the question • A lot of research being done on higher density and better safety • Perhaps 2 times higher density in a few years • Will safety suffer?
- 16. < Slide 16 > Agenda • Common physiological measurements • Battery limitations • Things that impact power • Data security
- 17. < Slide 17 > Three Ways to Get Data Into the Cloud 1. Device directly to cloud 2. Sensor to gateway to cloud 3. Sensor to cell phone to cloud
- 18. < Slide 18 > How Much Power Do Sensors Use?
- 19. < Slide 19 > Agenda • Common physiological measurements • Battery limitations • Things that impact power • Data security
- 20. < Slide 20 > Data Security • The FDA issued a guidance document at the end of 2016 regarding end-to-end security for medical devices. • End-to-end security requires: • Detect a device that is not authorized • Ensure the data is valid when received in the cloud • From a known device • The right data – right time, right user, etc • Accurate • Store data in the cloud securely • Ensure software updates come from right source
- 21. < Slide 21 > Data Security Technology • SecureRF Corporation has an encryption algorithm that runs on processors as small as 8 bits. • Most algorithms too slow, need powerful processors • Intrinsic ID Corporation generates secret key from random SRAM power-up state • Provides authentication device to cloud • SecurePush Corporation provides end-to-end solution with • System on a chip • Mobile app • Cloud service
- 22. < Slide 22 > Walt Maclay, Voler Systems Walt@volersystems.com Quality Electronic Design & Software Wearable Devices Sensor Interfaces Wireless Medical Devices
- 23. < Slide 23 >