Automatic Water Tank Overflow Controller using Ultrasonic Sensor

Every Indian household knows the routine: switch the pump on, forget it, and watch water pour off the terrace — or worse, run the pump dry when the sump is empty and burn the motor. This controller removes the human from the loop. A waterproof JSN-SR04T ultrasonic sensor mounted under the tank lid measures the water level continuously; the controller switches the pump through a contactor/relay at the low-level mark and cuts it at the full mark, with hysteresis so the pump doesn't chatter at the boundary. A second sensor (or float switch) on the sump/ground tank interlocks the pump: no water below, no pumping, and the buzzer plus LCD announce the dry condition. A manual mode covers testing, and a pump-runtime log helps spot abnormal cycles. The scope is stated plainly: it automates a domestic single-pump setup — it is not a municipal waterworks controller.

1. The JSN-SR04T pings the water surface at fixed intervals; the echo time converts to distance, then to level percent against the buyer-calibrated empty/full marks.
2. When the level falls to the low mark, the controller energizes the pump relay/contactor and logs a start event.
3. When the level reaches the full mark, the controller drops the pump and logs a stop event; the hysteresis band keeps the pump from short-cycling.
4. Before every start — and continuously while running — the sump interlock is checked; a dry sump blocks or stops the pump and raises the buzzer + LCD fault.
5. The LCD shows live level, pump state and any fault; the manual switch bypasses automation for testing, flagged clearly on screen.
6. The event log (level crossings, pump cycles, dry-run blocks) is kept for the report's data section and the buyer's own verification.

Tech stack:

• Arduino Uno (ATmega328P) or ESP32 variant
• JSN-SR04T waterproof ultrasonic sensor
• Sump float switch / second level sensor (interlock)
• Pump relay/contactor module
• 16x2 character LCD + buzzer
• Manual override switch
• Arduino IDE (C/C++ firmware)

• [Non-contact level sensing] Waterproof JSN-SR04T ultrasonic sensor measures tank level from under the lid — no floats to jam, no probes to corrode.
• [Automatic pump control] Pump starts at the buyer-set low level and stops at the full level, with hysteresis preventing rapid on/off cycling.
• [Dry-run protection] Sump-low interlock blocks pumping when the source is empty, protecting the motor; LCD + buzzer announce the condition.
• [Hysteresis band control] Separate start and stop levels with a configurable dead band — proper control practice, documented in the report.
• [LCD level display] Live level in percent plus pump ON/OFF state and fault flags on a 16x2 LCD.
• [Manual override mode] Panel switch forces manual pump control for testing and priming, with the LCD flagging MANUAL mode.
• [Pump runtime log] Start/stop events with timestamps are logged, so abnormal cycling shows up in the data for the report.

• Working overflow-controller prototype (controller, JSN-SR04T, sump interlock, pump relay, LCD, buzzer, demo tanks/pump)
• Complete firmware source code (level measurement, hysteresis control, dry-run interlock, logging)
• Circuit and wiring documentation with relay/contactor safety notes
• Component list with ratings
• Level-calibration and demo procedure guide
• Project report PDF (level-sensing background, ultrasonic theory, hysteresis control, methodology, test procedure)
• PPT presentation for final review
• Viva Q&A preparation document (ultrasonic ranging, hysteresis, contactor driving, dry-run physics)
• Setup and demonstration guide

• Demonstrated on scaled demo tanks with a small demo pump; real terrace-tank wiring and plumbing are the buyer's deployment by a qualified electrician/plumber.
• Ultrasonic readings need the buyer's own empty/full calibration; foam, steam or sloped tank lids can disturb readings — documented in the setup guide.
• The sump interlock needs its own sensor/float fitted at the source; the base prototype demonstrates it on the demo rig.
• Pump ratings are limited to the relay/contactor fitted; switching a large borewell pump needs a contactor sized by the buyer.
• Event timestamps need an RTC module (listed as an option); the base build logs sequence without wall-clock time.