An IoT based Senior Design project at SDSU in collaboration with Wind River Technologies featuring a home use stethoscope.

1. Sound Scope:
The IoT and the Future of Medicine
1

2. • Unsustainable increases in medical spending
• Significant portion is from waste or inefficiency
2
Sound Scope: The Need
2809 2916
3130
3308
3514
3723
3952
4207
4487
4781
2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
Estimated US Healthcare Expenditures ($US Billions)

3. Sound Scope: The Vision
3

4. Sound Scope: The Implementation

5. Sound Scope: User Experience

6. 6
Sound Scope: User Interface

7. 7
Sound Scope: Physician Experience

8. 8
Software: Website

9. Hardware
9

10. 10
Hardware: Case
Profile View
Top View

11. 11
Hardware: Final PCB Integration

12. 12
Hardware: Signal Detection
Stethoscope design
• Unchanged for hundreds of years
• Unable to record or amplify signals
• Vulnerable to ambient noise interference

13. 13
Hardware: Signal Detection
Sound Scope sensor technology:
• Piezoelectric sensors for simplicity
• Microphone for fidelity and accuracy

14. 14
Hardware: Signal Amplification and Filtering
Audio Op-Amp:
• High impedance input
• Single-ended power supply
• Differential Signal to RN52
Low Pass Filter :
• Second order Butterworth filter
• Approx. 5db per decade
• Fc = 1090 Hz
Bluetooth Module

Differential Signal

Sensor Input

Amplifier/Filter


15. 15
Hardware: Signal Amplification and Filtering

16. 16
Hardware: Power Requirements
Battery Rating:
• 3.7V Lithium Polymer Battery @ 300mAh
• Operating Voltage range = 4.2V to 3.5V
• Required Charging Voltage = 4.2V
• Low Cost, light weight, long life
• Form factor options
Typical system current draw Specs:
• RN52 – 60mA
• PIC – 4mA (LED’s)
• 3.3V Regulator – 1mA
• Amplifier/Filter Assembly ~ 85uA
Battery Capacity:
• Active Load testing with 250mA load yielded greater than 2
hours of battery life before reaching low battery cutoff
threshold voltage of 3.5V

17. 17
Hardware: Power Supply and Voltage Regulation
Battery Charge
Management
Wireless Charging
Input

3.3V Regulator

Battery Input 
Regulator Design:
• Small PCB footprint
• Low cost
• Easy implementation
• High current handling
• No heat-sink required
Battery Input

Voltage Regulator


18. 18
Hardware: Battery Charging and Monitoring
Inductive Charging

19. 19
Hardware: Battery Charging and Monitoring
Coulomb Counter

PIC
Microcontroller


20. 20
Hardware: Microcontroller Integration
Reduced Complexity:
• No buttons or charging cables
• Real-Time decision making
Smart Technology:
• Analog Accelerometer
• Auto On/Off
• UART communication w/ RN-52
• Power Down and Adjust Gain
• Battery Charging System
• Coulomb Counting/Polarity
• Relay Battery Level to App

21. Software

22. Software: Block Diagram

23. 23
• Bluetooth Routine
• Sequence for in APP connection
• Local BluetoothAdapter
• BluetoothServerSocket
• BluetoothSocket (similar to TCP)
• BluetoothProfiles
 HFP
 HSP (SCO)
 SPP profile
Software: Bluetooth Implementation

24. 24
Software: Bluetooth Protocol Stack

25. 25
Software: BT HSP/HFP Protocol Stack

26. 26
Bluetooth Profiles
• A2DP (Advanced Audio
Distribution Profile)
 Audio transfer both ways
 Two most important roles
 Source (BRC)
 Sink (SNK)
• RFCOMM Protocol
Profile
 Also know as SPP Profile
 Serial communication to
Microcontroller
Software: Bluetooth Integration

27. 27
Software: Bluetooth Serial Communication
Bluetooth Serial Port Profile (SPP) is used to implement Bi-directional communication.
• Increase Gain
• Decrease Gain
• Restart RN-52
• Periodic requests for battery
status
• Current Battery state

28. 28
Software: Device Battery Monitoring
A
B
C
D

29. Helix Device Cloud
CONNECT
MANAGE
BUILD

30. Helix Device Cloud

31. Achievements and Budget

32. • Designed and implemented previously non-existent
technology
• Combined two senior design projects into one
(inductive charging and Bluetooth stethoscope)
• Project completed two weeks ahead of schedule and
under budget
• Open ended design to allow for continued
development
Aether Engineering: Achievements

33. 33
Aether Engineering: Budget
$375
$150
$45
$300
$65
$165
$400
$2,000
Breakout Board
Stethoscope Housing
Sensors/Switches
Sample Stethoscope
Battery Components
Spare Parts
Circuit boards
unallocated

34. 34
Cost for mass Production
$14.80
$11.67
$6.03
$1.20
$.80
$2.00
Total: $36.50
Aether Prototype Cost to produce: $1500.00

35. 35
Aether at Design Day: 11 December 2015

36. Thank You