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The problem
Aquaponics — fish and plants in one recirculating loop — fails silently. Fish excrete ammonia, bacteria convert it to nitrite then nitrate, plants absorb the nitrate; if the pH drifts, the temperature spikes, or the pump stops at night, fish stress and plants stall, and the student discovers it a day too late. Manual test kits mean the system is checked twice a day at best. This project instruments the loop with an ESP32: a pH probe, a waterproof temperature sensor, a dissolved-oxygen probe and an EC probe report continuously, and the controller drives the circulation pump, aerator and an automatic feeder servo. The mobile dashboard is the daily interface — live tiles for each parameter, a 24-hour pH trend against the safe band, feed logging, and actuator toggles. Threshold alerts (low dissolved oxygen, pH out of band, pump fault) turn a twice-daily chore into continuous supervision, and the logged data gives the report real curves to discuss: the daily pH swing, the oxygen dip after feeding, the EC climb between water changes.
pH, dissolved oxygen, temperature and EC probes sample the fish tank on a 30-second cycle.
Follow the working sequence
How it works
- The pH, temperature, DO and EC probes sample the fish tank on a 30-second cycle through the ESP32's ADC and digital interfaces.
- Each reading is checked against configured safe bands (pH 6.8–7.2, DO ≥ 5 mg/L, temperature 24–28 °C).
- The firmware runs the circulation pump on its flood/drain schedule and switches the aerator based on the DO reading, overriding the schedule if oxygen drops.
- The servo feeder dispenses at the configured times and the dashboard counts feeds per day.
- Readings are published over Wi-Fi to the mobile dashboard, which renders live tiles, the 24-hour pH trend and actuator states.
- Any parameter leaving its safe band raises a dashboard alert; a pump-current anomaly flags a possible pump fault.
- Logged data is exported for the report, showing daily cycles the student can explain in the viva.
Tech stack:
- ESP32 (Wi-Fi telemetry + control)
- pH probe with conditioning board
- DS18B20 waterproof temperature sensor
- Galvanic dissolved-oxygen probe
- EC/TDS probe
- Mobile-first HTML/CSS/JS dashboard
- Relay modules, submersible pump, feeder servo
| Parameter | Value |
|---|---|
| Controller | ESP32 development board |
| pH range | 0–14, safe band 6.8–7.2 (configurable) |
| Temperature | −55 to +125 °C sensor; DS18B20 ±0.5 °C (datasheet) |
| Dissolved oxygen | 0–20 mg/L probe range; alert below 5 mg/L |
| EC range | 0–20 mS/cm (design target) |
| Sampling | Every 30 s (configurable) |
| Pump cycle | 15 min on / 45 min off (configurable) |
| Dashboard | Mobile-first web UI, Wi-Fi local |
Project features
- [pH monitoring] Industrial-style pH probe with on-board conditioning, read every 30 s and plotted against the 6.8–7.2 safe band on the dashboard.
- [Water temperature] Waterproof DS18B20 sensor (±0.5 °C per datasheet) tracking the 24–28 °C tilapia comfort zone.
- [Dissolved oxygen] Galvanic DO probe monitoring the 5 mg/L minimum, with a low-oxygen alert that also forces the aerator on.
- [EC / nutrient tracking] EC probe following nutrient build-up between water changes, shown as a dashboard trend.
- [Scheduled actuation] Circulation pump on a flood-and-drain cycle, aerator tied to DO readings, and a servo feeder with configurable daily feed times.
- [Mobile dashboard] Live parameter tiles, 24-hour pH chart, feed counter, actuator toggles and threshold alerts in a phone-first UI.
- [Alert logic] pH out-of-band, DO below minimum, temperature excursion and pump-current anomaly each raise a dashboard alert.
- [Data logging] Timestamped readings stored for the report's trend analysis and calibration records.
What is included
- Working aquaponics sensor prototype (tank-side unit with all probes)
- ESP32 firmware (sensing, scheduling, alerts, Wi-Fi telemetry)
- Mobile dashboard web app
- pH/DO/EC calibration procedure with buffer solutions guide
- Wiring diagram and plumbing layout
- Project report PDF (background, aquaponics chemistry, sensor theory, methodology)
- PPT presentation for final review
- Viva Q&A preparation document (pH, DO, nitrogen cycle, EC, calibration)
Limitations & prerequisites
- pH and DO probes need regular calibration with buffer solutions; readings drift without it — the calibration procedure is part of the deliverables and the student's responsibility.
- Ammonia is tracked via pH/temperature context and safe-band logic, not a direct ammonia sensor (direct NH3 probes are costly and fragile; stated honestly).
- The feeder servo doses dry pellets; portion size is set mechanically and verified by the buyer.
- Wi-Fi range limits the dashboard to local network coverage unless the buyer adds cloud forwarding (noted as extension).
- The prototype monitors one tank and one grow bed; multi-tank scaling is future scope.
Frequently Asked Questions
Why does aquaponics need continuous monitoring?
Because the fish–bacteria–plant loop is chemically coupled: a pH swing locks out nutrients for plants and stresses fish, and low dissolved oxygen can kill fish in hours. Twice-daily manual tests miss these events; continuous sensing catches them.
How is the pH probe calibrated?
With pH 4.0, 7.0 and 10.0 buffer solutions using the included two/three-point procedure. The dashboard shows when the last calibration was done, and the report documents the calibration readings.
What does the EC reading tell me?
Electrical conductivity tracks dissolved nutrients. A steady climb between water changes is normal; a sudden jump suggests overfeeding or a dead zone in the grow bed.
Can it run the system automatically?
The pump schedule, DO-triggered aeration and timed feeding are automatic, with manual overrides on the dashboard. Chemical dosing (pH adjusters) stays manual — deliberately, since wrong auto-dosing kills fish.
What fish and plants is it sized for?
The safe bands target tilapia and leafy greens (lettuce, basil) — the standard student aquaponics combination. Bands are configurable for other species.
Is this project suitable for a final-year project?
Yes — for Electronics, Electrical and IoT programs. It combines analog sensing, control logic, a mobile dashboard and real chemistry the student must understand. Suitable for B.E./B.Tech final-year projects in Electronics, Electrical and IoT & Embedded Systems.
Components & software requirements
- ESP32 (Wi-Fi telemetry + control)
- pH probe with conditioning board
- DS18B20 waterproof temperature sensor
- Galvanic dissolved-oxygen probe
- EC/TDS probe
- Mobile-first HTML/CSS/JS dashboard
- Relay modules, submersible pump, feeder servo
Delivery information
Built-to-order project. Delivery timeline is shared after order confirmation based on current queue.
Support terms
Complete documentation, setup guide, and viva preparation included. Support for setup and explanation provided.
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