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The problem
Households, hostels and small societies pay for every litre of water, yet most have no visibility into how much they actually use or where it silently goes. A leaking tap, a running toilet cistern or a cracked pipe can waste hundreds of litres a day without anyone noticing, and the loss only becomes visible when the water bill arrives. Municipal meters measure the whole building and cannot point at a specific line or time window, while smart utility meters are expensive, require utility cooperation and are rarely available for a single line or room. Students who want to build water monitoring for their final-year project usually stop at blinking an LED with a sensor, with no real flow measurement, no leak logic and no usable dashboard. This project closes that gap: a genuine flow-measurement instrument — pulse counting, datasheet-based conversion, configurable leak rules and a working usage dashboard — built on a low-cost ESP32, with honest accuracy limits stated up front.
Views usage on the dashboard and responds to leak alerts.
Follow the working sequence
How it works
- Water passes through the YF-S201 sensor, whose internal turbine spins a magnet past a hall-effect element, producing one pulse per rotor revolution on the yellow signal wire.
- The ESP32 counts these pulses with a hardware interrupt on a digital pin, computing the pulse frequency each second.
- Pulse frequency is converted to flow rate using the datasheet relation: Flow (L/min) = Frequency (Hz) / 7.5, i.e. 450 pulses per litre nominal.
- The firmware applies the leak rule: flow persisting through the configured no-usage window (e.g. 00:00–05:00), or daily usage above the configured baseline, raises a leak alert.
- The OLED refreshes with the current flow rate, the session total and any active alert, independent of the network.
- Every 2 seconds (design target) the ESP32's web server pushes the latest values to the dashboard: live gauge, daily and monthly usage bars, and the alert log.
- Totals are written to the ESP32's on-board flash (SPIFFS) so usage history survives restarts and is exportable as CSV.
Tech stack:
- ESP32 (dual-core, Wi-Fi) programmed in C++ via Arduino IDE
- YF-S201 hall-effect water flow sensor, 1/2-inch fittings (datasheet: 1–30 L/min, ±10% accuracy)
- 0.96-inch OLED display, 128×64, I2C
- ESP32-hosted HTTP web server + HTML/CSS/JavaScript dashboard
- SPIFFS on-board flash logging with CSV export
- 5 V DC power; buzzer + LED for local alerts
- Arduino IDE with ESP32 board package; SSD1306 OLED and Wi-Fi/web-server libraries; any browser for the dashboard
- Demo-loop hardware: breadboard or perfboard, jumper wires, 5 V DC supply (USB or adapter), short pipe stubs / vinyl tubing and clamps, active buzzer module and LED
| Parameter | Value |
|---|---|
| Controller | ESP32 development board, 240 MHz dual-core (datasheet) |
| Flow sensor | YF-S201 hall-effect, 1/2-inch fittings, 1–30 L/min working range (datasheet) |
| Pulse relation | 7.5 Hz per 1 L/min nominal, 450 pulses per litre (datasheet) |
| Sensor accuracy | ±10% of reading (datasheet; real accuracy depends on installation) |
| Pulse counting | Hardware interrupt on ESP32 digital input (firmware) |
| Local display | 0.96-inch OLED, 128×64 pixels, I2C interface |
| Dashboard | ESP32-hosted web page over Wi-Fi, refreshed every 2 s (design target) |
| Leak rules | Sustained flow in no-usage window or usage above baseline, configurable (firmware) |
| Power | 5 V DC, approximately 120–200 mA typical (expected) |
| Data retention | Usage history in on-board flash, CSV export (firmware) |
Project features
- [Interrupt-based flow measurement] The ESP32 counts YF-S201 pulses through a hardware interrupt and converts pulse frequency to L/min with the datasheet relation — 7.5 Hz per 1 L/min, 450 pulses per litre nominal — giving a genuine instrument reading rather than a guess.
- [Leak detection logic] A leak alert fires when low flow persists through the configurable no-usage window or when daily usage crosses a configurable baseline; thresholds are adjustable in firmware for different homes and hostels.
- [Live OLED readout] The 0.96-inch I2C OLED at the device shows the current flow rate, the running total and any active leak-alert text, so the meter is useful even with no phone or network nearby.
- [ESP32-hosted usage dashboard] A web dashboard served directly by the ESP32 over Wi-Fi shows the live flow gauge, daily and monthly usage bars and the leak-alert log — no cloud account, app install or internet needed for core use.
- [Usage logging to flash] Flow totals are stored in the ESP32's on-board flash and survive power cycles; the history is exportable as CSV for the project report and viva graphs.
- [On-device leak alert] A buzzer and LED signal a detected leak locally at the installation, independent of the dashboard or network.
- [Calibration factor] A single multiplier constant in the firmware trims the pulse-to-litre conversion to the actual installed pipe run, since the datasheet's ±10% figure assumes ideal straight pipe runs.
- [OPTIONAL ADD-ON — not in the base build: solenoid auto-shutoff] A relay-driven 12 V solenoid valve that closes the line automatically when a leak is confirmed. This is an optional customization, priced and built separately — the base project detects and alerts; it does not shut off water by itself.
What is included
- Working prototype: ESP32 + YF-S201 sensor + OLED on a demo pipe loop
- Complete firmware source code (pulse counting, leak logic, OLED, web dashboard)
- Wiring diagram and connection table
- Component list with exact part names
- Calibration procedure for trimming the pulse-to-litre factor
- Project report PDF (background, theory, methodology, results, limitations)
- PPT presentation for final review
- Viva Q&A preparation document (hall effect, interrupts, flow conversion, leak logic, ESP32 Wi-Fi)
Limitations & prerequisites
- The YF-S201 is an indicative instrument, not a certified billing meter: ±10% accuracy per datasheet, and real accuracy depends on straight pipe runs before and after the sensor, mounting orientation and water pressure.
- Readings below about 1 L/min fall outside the sensor's working range (datasheet 1–30 L/min); very slow drips may not register.
- The base build detects and alerts — it does not shut off water. Auto-shutoff needs the optional solenoid valve add-on.
- The dashboard is served by the ESP32 on the local Wi-Fi network; remote access from outside the home network needs a cloud or VPN layer (future scope).
- Leak detection is rule-based (flow pattern), not a second physical sensor — it flags suspicious flow, it cannot locate the leak.
Frequently Asked Questions
Is this project suitable for a final-year project?
Yes — for Electronics, E&TC, Electrical and IoT programs. It demonstrates a real sensor instrument (hall effect, interrupts, datasheet-based conversion), embedded firmware, rule-based anomaly detection and a working web dashboard, with honest accuracy limits that make strong viva material during the final review.
Which controller and sensor are used?
An ESP32 development board and a YF-S201 hall-effect water flow sensor. The YF-S201's datasheet specifies a 1–30 L/min range, ±10% accuracy and the conversion relation Flow (L/min) = Frequency (Hz) / 7.5 — the firmware implements exactly this relation with no deviation.
How does the leak detection actually work?
The firmware watches the measured flow pattern, not a second sensor. If flow continues through the configured no-usage window (typically night hours) or daily usage crosses a set baseline, it raises a leak alert on the OLED, buzzer and dashboard. Thresholds are configurable.
Does the dashboard need the internet?
No. The dashboard is a web page served directly by the ESP32 over the local Wi-Fi network — a phone or laptop on the same network opens it in a browser. Cloud backup or remote alerts from outside the home are optional future scope.
Is automatic water shutoff included?
No — the base project detects and alerts only. A relay-driven solenoid valve that closes the line on a confirmed leak is available as a clearly-priced optional add-on; it is not described anywhere as part of the base build or included in the base price.
What are the main limitations?
The sensor is accurate to ±10% per its datasheet and needs straight pipe runs for best results; flows below about 1 L/min are outside its range; the meter is indicative, not a certified billing meter; and the dashboard is local-network only.
Components & software requirements
- ESP32 (dual-core, Wi-Fi) programmed in C++ via Arduino IDE
- YF-S201 hall-effect water flow sensor, 1/2-inch fittings (datasheet: 1–30 L/min, ±10% accuracy)
- 0.96-inch OLED display, 128×64, I2C
- ESP32-hosted HTTP web server + HTML/CSS/JavaScript dashboard
- SPIFFS on-board flash logging with CSV export
- 5 V DC power; buzzer + LED for local alerts
- Arduino IDE with ESP32 board package; SSD1306 OLED and Wi-Fi/web-server libraries; any browser for the dashboard
- Demo-loop hardware: breadboard or perfboard, jumper wires, 5 V DC supply (USB or adapter), short pipe stubs / vinyl tubing and clamps, active buzzer module and LED
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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