The drifter project is tasked with developing an affordable

water quality measurement unit that allows high school

students and hobbyists to take part in collecting environmental

data. Jacobs is sponsoring the project in support of NASA. We

are developing the third version of the drifter, a design which

will incorporate three more water parameters. The

components and solar panels will be enclosed in a 3D printed

housing that is designed to offer greater functionality as a

tethered buoy, or as a true drifter in future adaptations. The

unit’s housing has been developed by a senior design team of

manufacturing engineering students to accommodate

modular adjustments to the internal electronics and options for

the deployment of the unit itself.

• Changed from Arduino Uno to Mega due an overlooked RAM

capacity limitation

• Added a buck converter module to prevent overcharging the

battery

• Modified housing to accommodate the Arduino and

Datalogger shield above the LCD for SD retrieval.

Approach

• Added three additional parameters to measure, making the

list of measurements:

• Dissolved Oxygen (New)

• Total Dissolved Solids (New)

• pH (New)

• Temperature (Old)

• Salinity (Old)

• Improve on the solar power design for more longevity

• Add a user interface to enable the user to:

• Modify sample frequency

• Turn On/Off parameters

• Take on-demand samples

• Arduino Mega is the brain of the device.

• Connects the 4 probes to capture and store the

data from each.

• D-Pad and LCD screen providing a simple

interface to adjust parameters and to allow

access to the calibration procedure while in the

field.

• The keypad and LCD will be encapsulated in the

housing with ease of access in mind.

• Solar power system.

• 4.5W solar panel array to maintain a battery

charge

• 12,000 mAhrs, 6 V AGM sealed lead-acid

battery

• Each of the probes were chosen with three aspects in mind.

• Industrial grade quality

• Cost

• Equipment complexity

• Signal Noise - One may experience a problem with the

sensors conflicting with each other by providing unwanted

noise and/or cross talk when taking measurements simultaneously

• Heat - Internal heat of electrical housing

- Summer heat

- Solar panel baking from summer rays

• Security – Drifter will be deployed in public area and is

subject to vandalism and theft.

.

Drifter Project

Background

Hardware

Remediation

Challenges & Concerns

Circuit

Conclusion

Results

EE 2.12 - Water Quality Drifter

Will Poeppelmeyer Isaac Bondoc Jacob Johnson John Marquez

Previous drifter

deployed by

mooring to a dock

New drifter

housing designed to

allow flexibility of

components and

deployment methods

The previous drifter transmits temperature and salinity

measurements to Twitter with the recurring cost of cell phone

service. Issues arose when cloudy weather caused insufficient

power and the periods without data, and water conditions

skewed probe readings during long outings.

Project Manager

AcknowledgementsMentor: Lee HinkleSponsors: Andi Hollier, Dr. Lisa VanderbloemenDirector: Dr. Stan McClellanProfessors: Dr. Bill Stapleton,

Dr. Karl Stephan,Dr. Austin Talley

Battery overcharging was prevented by a voltage regulator. The solar panel wiring in series and parallel was chosen to provide

enough voltage to charge the battery during more daytime, while keeping a priority towards current for charging.

Test Cases Specifications Results Pass/Fail

Solar Charging

Time

Input: < 7.5V, 300 mA

Output: Charge the

battery, from 0%, enough

to start datalogging

4.97V to 5.84V after 2

days using a sleep

mode simulated current

draw.

6.16V after 6 days of

“good” weather

PASS

User Interface Input: Directional/Select

Buttons

Output: Initial Menu,

Accessibility to each

option, Modifiable

Parameters

Correct display of initial

menu

all options are

accessible

All parameters are

Modifiable

PASS

Sleep Mode Input: Idle sleep mode

Output: Decrease in

overall power

consumption

Inconclusive Untested

Data Collection Input: Minimum sample

rate and sampling

Output: Measurement

with corresponding

timestamp

Stores all measurement

data

Each sample has

correct timestamp

PASS

Reliability Window Input: 15 minute sampling

frequency

Output: Continued data

recordings which do not

deviate considerably from

past values.

Ran without sleep

mode and solar for 96

hours.

Almost 4x sleep mode

current and lasted 4/7

of required days.

PASS