1. Final Project Review
Team Maji Safi
April 19, 2016 1 1 1

2. Maji Safi Advisor Prof Sequeira
Jason Arble (EE)
Peter Balkam (EE)
Kaitlin Menzie (CSE)
Minh Tran (CSE) 2 2 2

3. Problem: Economic Water Scarcity
Currently:
Many people in developing countries only have access to unimproved water sources, which they must walk a great distance to reach
Humanitarian organizations and environmental engineers can’t get the data they need to implement sustainable long term solutions
Our solution:
Create a cheap, simple device to alleviate the effects of water scarcity before
Sensors will be housed in easily-deployable “bubble”
Local users can access data through SMS; the general public can get larger amounts of data through the web app 3 3 3 3

4. Block Diagram 4 4 4 4

5. Device Sketch 5 5 5 5

6. Proposed FPR Deliverables
Jason
Design new, more compact, more robust case (3D print)
Design more compact power supply (PCB)
Add power switch to accessible location
Peter
Build Android App for sending the text messages to ease use among smartphone owners.
Consider more advanced data sampling methods.
Minh
Transfer microcontroller, GSM circuit onto barebones ATmega328
Sleep/Power Down Program Routine
Add SD card onto circuit
Kaitlin
Complete administrative interface
Have website completely done
Investigate future sensor possibilities 6 6 6 6

7. System Enclosure (Alpha)
Requirement
Status
Waterproof No
Buoyant
Yes
Stable
Contains Entire System
Cost Effective
No ($62)
Compact
Yes (4000 ㎠)
Aesthetically Appealing

8. System Enclosure (Beta)
Requirement
Status
Waterproof
Yes
Buoyant
Stable
Contains Entire System
Cost Effective
Yes ($30)
Compact
No (5600 ㎠)
Aesthetically Appealing No

9. Waterproofing Alpha Enclosure:
Known that 3D prints are not waterproof by testing smaller models
Beta Enclosure:
Waterproof but took several iterations:
Silicone caulking- failed
J-B Weld WaterWeld - success
Rust-Oleum LeakSeal used as backup

10. Schematic for Printed Circuit Board
Used Eagle Software to create double sided PCB
Includes atmega 328, GSM, all sensor ports and reset switch
Added additional ports for future sensors
All Digital Pins are accessible for expansion 10 10 10 10

11. Printed Circuit Board 11 11 11 11

12. Printed Circuit Board 12 12 12 12

13. Printed Circuit Board 13 13 13 13

14. Power Supply & Requirements
Power requirements and and hardware has not changed since CDR. There was no need to alter the power system.

15. Mobile App Enter the Cell number of the device you want to use
Vary the transfer and sample Rate as needed
Can request a single run of the sensors.
Can request device stops sampling and sending messages

16. Mobile App Adjust Sample Rate and Message Rate
Monitor Incoming Text messages.

17. Mobile App Version 2 All functions of last version
In addition can request the microcontroller writes to an SD card instead of sending messages.
Allows user to set the file name to be saved, as well as the duration to collect data for

18. Turbidity Sensor Calibration to a standard too expensive, impractical
Provides a rough “eyeball” estimate of NTU measurement
Impossible to determine potability (high sensitivity, narrow resolution, inaccurate)
Using manufacturer’s specs (shown right), we found a linear approximation of the voltage-NTU relationship.

19. SD Card Works to record data
Can’t implement on a single Atmega328 (Flash Mem. Constraint)
Additional cost to implement (+$6)

20. Sampling Code Functionality
Currently:
The microcontroller will take samples at a set interval.
After a set time the samples are averaged and the result is sent out.
Both the sample time and the sample rate can be changed remotely by SMS. 20 20 20 20

21. Sampling Code Functionality21 21 21 21

22. App updates Improvements Setup & deployed to production environment
Refactor and add routes
Added data views
Problems
Had to redo authentication for administrators & reconfigure all middleware

23. Server (AWS EC2 instance)
Web App Overview
Bubble
Twilio
User (water gatherer)
Data Users
Website
Device Admins
Server (AWS EC2 instance)
Mobile Site
RDB (PostgreSQL)
App (node.js) 23 23 23 23

24. App routes Text Maji Safi at 781-325-4725 Method Parameters Route Name
Route Purpose
GET -
index
Display home page
POST
location, radius
data
Search for devices in an area
texts/test
Graphically send a text with the server
recipient, message
query
texts
Twilio endpoint; responds to text differently based on whether the sender is a registered device.
If it is, the server treats the text as a test result and updates the database. If it’s not, the device treats the text as a location and responds with the 3 closest devices and their water quality.
Text Maji Safi at

25. Dashboard

26. More routes Method Route Name Route Purpose GET, POST register
Create a new administrator account
login
Login to an existing admin account
GET
admin
Administrative dashboard; add, see, edit, delete your devices
Device info
View/change settings for a device, text device, see all device results
devices/add
Add a new device; texts device with initial settings
POST
devices/update/{id}
Update device info; texts device with new settings
devices/delete/{id}
Delete device; texts device “STOP” 26 26 26 26

27. System Cost Item Development Cost Production Cost (1000)
Water Detector
$0.10 $
TSW-10 Turbidity Sensor
4.66
3.95
pH Sensor
29.50
27.19
Temperature Sensor
1.50
1.35
SIM Card
0.99
GSM2-Click w/ antenna
49.00
ATmega328P-PU
3.10
1.85
NXP LCP1768
46.00
Abandoned
8GB Micro SD Card
7.63
6.14
SD Card Slot
1.66
Resistors/Capacitors/16MHz Clk
1.02
Li ion battery x2
29.90
23.92
Solar Panel
29.00
23.20
DC-DC Converter
9.95
Charger
17.50
3D Print
60.92
Total
292.43

28. Final Product Specifications
Size
5600 ㎠
Power Consumption
1.35 W
Battery Life (w/o solar generation)
18.52 hr
Enclosure
Water resistant, Buoyant, Stable
pH Sensor Accuracy
± 1
Turbidity Sensor Accuracy
± 100 NTU
Temperature Sensor Accuracy
± 3°C
Cell Phone Response Time
< 30 seconds
Server Response Time
< 1 minute
Development Cost
$292.43
Production Cost (1000)
$227.92

29. DEMO