1. Cumulative Design Review
Team Maji Safi
March 3, 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 CDR Deliverables
Jason
Improve accuracy of water sensor
Power supply using a renewable energy source
Create deployable enclosure for current sensors, and MCU
Peter
Build submersible temperature sensor
Refactor & adapt main code to LPC1768
Adapt GSM2 Uno code to work on LPC1768
Stripped down version of Arduino MCU
Minh
Refactor & adapt main code to LPC1768
Build strip down version of Arduino
Implement external interrupts GSM2-LPC
Include storage device interface (data logging)
Corrections to turbidity sensor reading
Kaitlin
Have web app in production
Have prototype of image processing setup 6 6 6 6

7. System Enclosure Requirements: Waterproof Buoyant
Must be able to contain:
microcontroller
GSM module
sensors
Inspiration ->
om/

8. Our Enclosure
Our current enclosure uses 4” PVC pipe capped at both ends, sealed with silicone caulking. It is:
Waterproof
Unknown if buoyant
Able to contain GSM, microcontroller, sensors
Also contains power supply which is an added bonus

9. Schematic for Printed Circuit Board
Using eagle software
Includes atmega 328, GSM, all sensor ports and reset switch 9 9 9 9

10. Printed Circuit Board 10 10 10 10

11. Choice of Microcontroller
The ATmega328 has libraries we need
Don’t need extra features from LPC1768
Has enough I/Os for Sensor & GSM
Include SD card for onboard storage
Allows users to record & store
record & send (uses more power)
Final footprint size 11 11 11 11

12. Power Supply & Requirements
1.35W 5V) required for sensors, microcontroller and GSM module
18-hours of battery capacity (to account for night time and periods of clouds) mAh of battery capacity

13. Charging Circuit
Able to safely charge the Li-ion batteries from the solar panel while supplying 3.7 VDC to the load
500mA max charge current

14. Solar Panel
6V operating voltage (fulfills Requirement of Charging Circuit)
17% efficiency
2W max power (fulfills Requirement 1)
110mm x 140mm - small and light enough to be mounted to buoy

15. Battery Pack 2x Li-Ion batteries (shown) in parallel 3.7V
2 x 2500mAh (fulfils Requirement 2)
500mA optimal charge rate

16. Voltage Booster and Breakout
Input:3.7 VDC from batteries/charger
Output: 5.2 VDC to Arduino/GSM/sensors
90% efficient
Uses Ti TPS61090 Boost Converter

17. Improving the Water Sensor
No robust solution with additional hardware
Software solution:
Use the pH sensor to make the logic more robust
If the pH is between 5.6 (acidic rain) and 8.5, it likely that there is water

18. New 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. 18 18 18 18

19. New Code Functionality19 19 19 19

20. 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

21. Proposed FDR 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
Investigate improvements in device rating algorithm
Investigate future sensor possibilities 21 21 21 21