Amulet: An Energy-Efficient, Multi-Application Wearable Platform

Size: px

Start display at page:

Download "Amulet: An Energy-Efficient, Multi-Application Wearable Platform"

Adam Adams
5 years ago
Views:

1 Amulet: An Energy-Efficient, Multi-Application Wearable Platform Josiah Hester*, Travis Peters, Tianlong Yun, Ronald Peterson, Joseph Skinner, Bhargav Golla*, Kevin Storer*, Steven Hearndon*, Sarah Lord, Ryan Halter, David Kotz, Jacob Sorber* *Clemson University and Dartmouth College amulet-project.org SenSys 16 Nov 15, 2016

2 2 Wearables Wristbands Smartwatches Long lived wearables usually for fitness sensing, with longer lifetimes, but closed source and hardware. Very flexible development platforms, with short lifetime, often closed operating systems and hardware.

3 3 Tradeoffs Wristbands Pros: Long lifetime Cons: Closed platform Not flexible Smartwatches Pros: Flexibility Cons: Closed hardware or software Short lifetimes

4 4 Shortcomings Flexibility Not open Lifetime Does not enable mhealth

5 mhealth mobile systems in healthcare Courtesy: Courtesy: experientia.com Courtesy: good.is Courtesy: seniorcarecenter.com Courtesy: sana.mit.edu

6 Amulet Platform 6

7 7 This Talk 1. Design 2. Implementation 3. Evaluation

8 8 Design Multiple applications Need app isolation Long battery lifetime Designed for low power operation Developer tools Focused on energy Usable Open Source and Hardware

9 9 Multi Application Flexibility Multiple developers, multiple apps Users have different needs Security Sandboxing for isolation among apps Access control for sensors, peripherals

10 10 Lifetime Need weeks and months Not hours and days! Support long term studies, deployments

11 11 Developer Tools 1. Where is my energy going? 2. How does the environment, and the user behavior change energy? 3. What can I change in my code to increase the lifetime?

12 12 Open Open Source Use, adapt, change Open Hardware Remix, redo, enhance

13 13 Amulet 1. Open Hardware Wearable 2. Amulet-OS and API 3. Amulet Firmware Toolchain 4. Amulet Resource Profiler and UI

Device Sensors 3-axis gyroscope, ST Electronics L3GD20H 3-axis nano-power accelerometer, Analog ADXL362 Ambient light, UVA/B, temp, sound, battery Computing Nordic nrf51822, ARM Cortex M0, 32K RAM,

14 Device Sensors 3-axis gyroscope, ST Electronics L3GD20H 3-axis nano-power accelerometer, Analog ADXL362 Ambient light, UVA/B, temp, sound, battery Computing Nordic nrf51822, ARM Cortex M0, 32K RAM, 256K FLASH TI MSP430FR5989, 2KB SRAM, 128KB FRAM microsd card slot Network BLE radio (Central & Peripheral) Supported protocols: heartrate, battery, running services Output Monochrome 128x128 Sharp Memory LCD or two single color LEDs haptic feedback via vibrator motor Input two buttons capacitive touch slider accelerometer Battery Polymer Li-Ion,110 mah, 3.7V,MCP73831 recharge 14

15 15 Amulet-OS Apps: finite-state machines w/memory set of states, variables, and event handlers all state is explicit, in non-volatile storage no threads: handlers run to completion API calls post event to relevant system service

16 16 Amulet-OS App1 App2 AppN Core Services Board Support Amulet API Logging Timer Crypto Power Network Hardware Sensors Serial SD Card Analog Bluetooth GPIO Core Interface Board Interface Watchdog UI Clocks Interrupts... void AmuletSubscribeInternalSensor( uint8_t sensor_id); uint16_t AmuletGetHR(); uint8_t AmuletGetBatteryLevel(); uint16_t AmuletGetLightLevel(); uint16_t AmuletGetTemperature(); uint16_t AmuletGetAudio(); int16_t AmuletGetAccelX(uint8_t idx); void AmuletBoldText(uint8_t x, uint8_t y, char_array message); void AmuletClearRect(int16_t x, int16_t y, uint8_t w, uint8_t h); void AmuletHapticSingleBuzz(); uint8_t AmuletLogAppend(uint8_t log_name, char_array line_contents);... Subscribe to sensors, log data, communicate, interact.

17 17 Amulet Firmware Toolchain Firmware analysis, translation, compile Manage multiple applications Analyze for isolation Profile for energy and memory usage App Isolation and Resource Profiling

18 18 AFT Workflow QM File with Amulet C Analyzer & Translator Analyzer & Translator Some restrictions on C: 1. no dynamic memory 2. no pointers 3. no recursion Check app access control and language violations.

19 19 AFT Workflow QM File with Amulet C Analyzer & Translator Analyzer & Translator device profile C code Resource Profiler Resource Profiler Profile energy and memory resource usage.

20 20 AFT Workflow QM File with Amulet C Analyzer & Translator Analyzer & Translator device profile C code Resource Profiler Resource Profiler AmuletOS C code App Merger C code Energy model ARP-View Libraries custom code existing tool Compiler Linker Installer binary code firmware image

21 21 Amulet Resource Profiler (ARP) QM File with Amulet C Analyzer & Translator Analyzer & Translator device profile C code Resource Profiler Resource Profiler AmuletOS C code App Merger C code Energy model ARP-View Libraries custom code existing tool Compiler Linker Installer binary code firmware image

22 22 Amulet Resource Profiler Designing for low power is not enough Developers can always write bad apps This can be because of ignorance Or because tools don't exist! Must support developers!

23 Amulet Resource Profiler 89% of users consider battery lifetime the most important feature[1]. Energy is a first class concern for users. Why not for developers? [1] Your smartphone s best app? battery life, say 89% of Britons. The Guardian, May

24 24 Resource Model Concerned with energy Secondary concern: memory Model the device itself One time, at device manufacture Model the application(s) Compile time

25 25 Device Energy Model Hardware Info Device Profile Steady state draw Sleep currents Sensor power costs Device memory API Calls Generated once per device type.

26 26 App Energy Model Device Profile Analyze App(s) Construct // Update temperature if changed: uint8_t new_temp = AmuletGetTemperature(); if (new_temp!= temp) { temp = new_temp; char temp_disp[5]; AmuletITOA(temp, temp_disp); char F[2] = "F"; AmuletConcat(temp_disp, F); AmuletClearRect(0,75, LCD_HORIZONTAL_MAX, MEDIUM_FONT_SIZE); AmuletMediumCenteredText(75, temp_disp); refresh_display = 1; } Model

27 27 ARP-View Interface for energy insights Generated at compile time Can model user behavior Model environment triggers as well Explore design tradeoffs

28 28 ARP-View Energy focused development.

29 Evaluation 1. Battery Lifetime Power (mw) 1.5 1.0 0.5 0.

29 29 Evaluation 1. Battery Lifetime Power (mw) days days days 214 days 192 days 54 days 17 days 14 days 67 days 39 days Clock Fall Detect Pedometer Sun Exposure Temperature Heartrate Battery Log HR Log EMA Clock+HR+Fall Battery lifetimes ranging from 2 weeks, to 8 months.

30 30 Evaluation ARP Prediction Accuracy Power (mw) days days days 214 days 192 days 54 days 17 days 14 days 67 days 39 days Clock Fall Detect Pedometer Sun Exposure Temperature Heartrate Battery Log HR Log EMA Clock+HR+Fall Predictions Actual Prediction accuracy of 90-98% for our apps.

31 31 User Study ARP-View: usability and energy what is the developer energy mental model? does ARP-view force devs to think about energy? 10 programmers, 30 minute task and survey 9/10 subject reported positive outcomes ARP-view assists developers.

32 32 Pilot Study mhealth: smoking cessation surveys monitored heart rate using BLE presented surveys at intervals during the day recorded survey responses and heart rate 6 participants, 1 week, 48 hours of deployment usability survey that informed hardware rev(s) Demonstrates mhealth feasibility.

33 33 Evaluation Great battery lifetimes 2 weeks to 8 months Accurate prediction results 90-98% accuracy Usable by users, researchers, and developers.

34 34 Future Secure firmware toolchain OTA firmware updates and security Body are health network (BAHN) Extending the reach of Amulet Energy Harvesting Wearables Solar, or vibration powered, no charging! Priority: Enabling your applications!

35 Summary Amulet is 1. Open source, open hardware, multi app wearable device 2. Firmware toolchain isolating applications and resource profiling. 3. Energy focused application development with ARP-View amulet-project.org 35

Computational Jewelry for Mobile Health: the Amulet

Computational Jewelry for Mobile Health: the Amulet Kelly Caine*, Ryan Halter, David Kotz, Sarah Lord, Jacob Sorber* *Clemson University and Dartmouth College June 2017 mhealth The use of mobile computing