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The problem
Aquarium water evaporates daily, and the falling level concentrates waste while stressing fish; meanwhile a stuck heater can cook a tank overnight. Hobbyists check both by eye, which fails the moment they travel. The engineering answer is a controller that maintains the level itself and watches temperature continuously. This project builds a student-scale IoT aquarium controller on an ESP32: a float switch at the rim detects low water and runs a small submersible pump from a reservoir to top off the tank, while a waterproof DS18B20 probe tracks temperature. The OLED shows level and temperature live, and the ESP32 publishes both to a phone dashboard with alerts for low water and out-of-range temperature.
Level switch at the tank rim reporting whether the water level is low.
Follow the working sequence
How it works
- The float switch at the tank rim reports the water level to the ESP32; the DS18B20 probe reports temperature on the same loop.
- When the level drops below the switch point, the ESP32 energizes the pump relay and the reservoir pump tops off the tank.
- The pump stops when the float switch rises again, or when the firmware safety timeout elapses — whichever comes first.
- The OLED continuously shows LEVEL OK / TOPPING UP and the live temperature reading.
- Over Wi-Fi the ESP32 publishes level state and temperature to the phone dashboard on a periodic heartbeat and immediately on alert conditions.
- If temperature crosses the configured high limit, the dashboard raises a high-temperature alert and the local buzzer sounds.
Tech stack:
- ESP32 development board
- Float switch level sensor
- Mini submersible pump with tubing
- DS18B20 waterproof temperature probe
- 0.96-inch OLED display
- Blynk-style IoT dashboard (phone alerts)
- Arduino IDE (C/C++ firmware)
| Parameter | Value |
|---|---|
| Controller | ESP32 development board |
| Level sensing | Float switch at rim (design) |
| Top-off pump | Mini submersible pump, relay-switched |
| Pump safety cap | Approximately 60 s per run (design) |
| Temperature | DS18B20, ±0.5 °C per datasheet |
| Display | 0.96-inch OLED |
| Alerts | Wi-Fi dashboard push + local buzzer |
| Power | 5 V regulated supply (design) |
Project features
- [Automatic top-off] A float switch detects low water and the ESP32 runs the submersible pump until the level is restored, with a firmware run-time cap as a safety limit.
- [Water temperature monitoring] A waterproof DS18B20 probe reports tank temperature with the sensor's ±0.5 °C datasheet accuracy.
- [OLED live display] Level state and temperature are shown continuously on a 0.96-inch OLED.
- [Wi-Fi telemetry and alerts] Level and temperature publish to a phone dashboard over Wi-Fi, with low-water and high-temperature alerts.
- [Pump safety timeout] Firmware caps each pump run (design approximately 60 seconds) so a stuck float switch cannot flood the setup.
- [Manual pump button] A push button runs the pump on demand for water changes and priming.
- [Dashboard setup guide] Step-by-step instructions connect the ESP32 to the notification dashboard on the student's own phone.
What is included
- Working model aquarium setup with float switch, pump, temperature probe, ESP32 and OLED
- Complete firmware with commented level-control and telemetry logic
- Phone dashboard setup guide with screenshots
- Wiring diagram and connection table
- Project report PDF (background, system design, firmware logic, IoT architecture)
- PPT presentation for final review
- Viva Q&A preparation document (float switches, DS18B20, relays, ESP32 Wi-Fi)
Limitations & prerequisites
- The prototype is a small demonstration tank, not a full-size aquarium — pump flow and level geometry are sized for the model.
- Temperature accuracy follows the DS18B20 datasheet (±0.5 °C); no independent calibration measurement is claimed.
- The pump safety timeout is a firmware design value verified functionally on the buyer's build, not a certified flood-prevention figure.
- Wi-Fi alerts depend on the buyer's own network and the third-party dashboard service; no uptime is guaranteed for external services.
- The system tops off evaporated water only — it does not filter, heat or dose the water.
- Battery operation is not included; the unit runs on a 5 V adapter.
Frequently Asked Questions
How does the auto top-off work?
A float switch at the rim detects when evaporation drops the level. The ESP32 then runs a small pump from a reservoir until the switch floats back up, with a firmware timeout as a backup stop.
What stops the pump from flooding the tank?
Two layers: the float switch itself cuts the pump at the target level, and a firmware run-time cap stops the pump after about 60 seconds even if the switch sticks.
How accurate is the temperature reading?
The DS18B20 is rated ±0.5 °C in its datasheet, which is the figure the project uses — no better accuracy is claimed.
How do the phone alerts work?
The ESP32 publishes level and temperature to a Blynk-style dashboard over the buyer's Wi-Fi, with alerts for low water and high temperature. The setup guide covers the whole configuration.
Can it control a heater or filter too?
Not as built — level top-off and temperature monitoring only. Heater relay control is listed as future scope.
Is this project suitable for a final-year project?
Yes — for Electronics and IoT & Embedded programs. It covers waterproof sensing, relay-switched actuation, safety timeouts and a full device-to-phone telemetry loop. Suitable for B.E./B.Tech final-year projects in Electronics and IoT & Embedded.
Components & software requirements
- ESP32 development board
- Float switch level sensor
- Mini submersible pump with tubing
- DS18B20 waterproof temperature probe
- 0.96-inch OLED display
- Blynk-style IoT dashboard (phone alerts)
- Arduino IDE (C/C++ firmware)
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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