IoT buoy · Oyster aquaculture

The world is your oyster.
Protect what lies beneath.

Welcome to pHixHub, the dashboard for the pHixer! The pHixer is a low-cost water monitoring buoy, reading five different water quality signals live, streams them to ThingSpeak, and activates a water pump once conditions venture outside a safe range for oysters.

View live dashboard How the response works
5
Sensors monitored
24/7
Autonomous watch
AUTO
Pump response, no manual trigger
ARDUINO
Uno R4 WiFi core
Onboard sensors

Five sensors for ideal water quality

Each sensor has been hand-calibrated against known references before it begins monitoring, so every value on the dashboard is a reading pHixHub can act on.

pH

Three-point calibration across acidic, neutral, and basic buffers.

TDS

Total dissolved solids, tracking salinity and mineral load.

Turbidity

How clear the water is determined by cloudiness or haziness

Dissolved Oxygen (DO)

Oxygen levels available for the oysters, related to temperature

Temperature

PT-1000 RTD probe for stable, thermal heat readings.

User interface

Live from ThingSpeak

Point pHixHub at your channel to pull the latest feed. Readings refresh automatically every 20 seconds.

Not connected — enter your channel ID to go live.

Where pHixer is right now

Plotted against U.S. sites with documented water quality issues
Buoy Reference site

Buoy position

LATITUDE
—
LONGITUDE
—
Last updated: never
Distance to reference sites
WATER PUMP
STANDBY
All pump-linked parameters within range.
Autonomous response

When something goes wrong

The pHixer not only monitors, but regulates parameters. pHixHub highlights the chain of events.

1

Reading taken

Each sensor is polled on a fixed cycle and compared against its safe range for oysters.

2

Threshold check

If a value falls outside range, the buoy flags it and logs the exceedance to ThingSpeak.

3

Relay triggers

The onboard relay switches on the water pump, drawing from an isolated battery pack.

4

Alert sent

pHixHub surfaces a notification here and, if enabled, a browser push alert.

ParameterSafe rangeOut-of-range response
pH7.5 – 8.5Pump cycles to dilute and rebalance
TDS500 – 1500 ppmPump exchanges water to correct salinity
Turbidity< 50 NTUPump flushes suspended sediment
Dissolved O₂> 5 mg/LPump circulates to reoxygenate
Temperature10 – 28 °CLogged; flagged for manual review
For the farmer

What to do about it

Along with the autonomous water pump, here's some recommendations for what oyster farmers can do for each condition, backed by research.

When pH is low

Ocean acidification

  • Use a water treatment system with a buffering agent, like sodium carbonate ash, to stabilize pH.
  • Grow out seagrass beds nearby — they improve seawater quality and lower pH-depressing CO₂ levels.
Source: thecounter.org — Ocean acidification & Dungeness crabs
When dissolved oxygen is low

Hypoxia / dead zones

  • Activate the water pump to create circulation and bubbles, breaking up hypoxic dead zones.
  • If the condition persists, relocate to a site with deeper, oxygen-richer water.
Source: islandinstitute.org — Mook Sea Farms pump system
When turbidity is high

Suspended sediment

  • Raise the cage upward in the water column to avoid the most turbid layer.
  • Activate the water pump to help disperse the concentration of suspended particles.
Source: sciencedirect.com — Turbidity research
When temperature is high

Heat stress

  • Set up sprinklers to mist the cages, preventing oysters from overheating in solar radiation.
  • Submerge the cage in deeper water to reach cooler temperatures.
Source: kuow.org — Shellfish farmers after the heat wave
When salinity / TDS is low

Freshwater intrusion

  • If floods or heavy rain drop salinity below 10 ppt, relocation is often the best option.
  • Lower cages toward the ocean floor, where denser, saltier water tends to settle beneath the freshwater layer.
Source: aquila.usm.edu — Breton Diversion report
When a reading is irregular, pHixHub will match a recommendation into the notification feed automatically. This way, you see the actual sensor value and what to do about it in one place.
Stay informed

Notifications

A running log of every threshold exceedance and pump activation, newest first.

Browser alerts are off.
No events yet — connect a channel above to start watching for alerts.
How we built it

Our process

From the idea of oysters, to a buoy, the stages our team worked through to get pHixer fixing.

1
Research

Defined the problem

Studied the water quality conditions oysters need to survive and identified pH, salinity, turbidity, dissolved oxygen, and temperature as the parameters that matter most. Visited an oyster hatchery to look at real monitoring graphs for how these conditions are tracked and regulated.

Oyster hatchery monitoring graphs
Oysters at the hatchery
2
Design

Designed the buoy system

Planned the sensor layout, enclosure, and power system around an Arduino Uno R4 WiFi, and mapped out how each sensor would feed into the relay-controlled pump.

Building the buoy enclosure
3
Calibration

Calibrated each sensor

Ran dedicated calibration sketches against known reference solutions for pH, TDS, turbidity, and dissolved oxygen, and set up the PT-1000 RTD probe for temperature.

Team starting sensor work
Sensor calibration
4
Build

Built and wired the buoy

Assembled the enclosure, wired the sensors and pump relay, and set up GPS and ThingSpeak connectivity so readings stream live from the water.

Wiring the buoy system together
Programming the buoy
5
Testing

Tested and debugged

Ran the full system end to end, tracked down wiring and field-mapping issues, and confirmed the pump responded correctly to out-of-range readings.

Testing sensor accuracy
6
Deployment

Deployed and built pHixHub

Put the buoy on the water and built pHixHub, the dashboard that turns its live ThingSpeak feed into readable, actionable information.

Building the buoy enclosure together
Who built this

About us

The pHixer and pHixHub were built and maintained by the three of us.

Lucy, Shreya, and Manav
Lucy

Lucy

Hardware Engineer & Designer
Kinston, NC · Nursing & statistics

Lucy is a junior at Arendell Parrott Academy and serves as hardware engineer and designer on the project. She built the interior wiring and designed the buoy and its presentations. Her academic interests include statistics and biology. She is also an active volunteer at her local soup kitchen and runs cross country and plays basketball.

Contact: lucyojones8@gmail.com
Shreya

Shreya

Lead Programmer & Writer
Chapel Hill, NC · Neuroscience & bioethics

Shreya is a junior at Durham Academy and serves as lead programmer and writer on the project. She developed the firmware powering the pHixer buoy, built the pHixHub dashboard, and authors the team's research documentation. Her academic interests include neuroscience and bioethics. She is also a member of her school's debate team and tennis program.

Contact: shreyajosephh@gmail.com
Manav

Manav

Lead Researcher
Weddington, NC · Data science & finance

Manav is a senior at Weddington High School and serves as the lead researcher for the pHixer project. He compiled sources, statistics, and data to establish the project's background and motive. His academic interests include data science and finance. He is also a member of the school's Science Olympiad and cross-country team.

Contact: manavnairr@gmail.com