An Arduino Uno–based water tank level monitor with automatic pump control, built and simulated in Wokwi, then converted into a full KiCad 10 PCB design.
The system uses an ultrasonic sensor to measure water level, displays the percentage on a 16x2 LCD, and switches a pump on/off through a relay — either automatically based on level thresholds, or manually via a pushbutton.
- Real-time water level percentage on a 16x2 LCD
- Auto mode — pump switches ON/OFF automatically based on tank level
- Manual mode — pump toggled by a pushbutton, with an overflow safety cutoff still active
- One-button calibration to set the tank's empty-level reference (saved to EEPROM, survives power loss)
- Relay output for driving a real pump
- Designed in Wokwi first, then laid out as a real PCB in KiCad — 0 DRC / 0 ERC violations
The HC-SR04 ultrasonic sensor is mounted facing down into the tank and measures the distance from itself to the water surface. That distance is converted into a fill percentage relative to a calibrated "empty tank" reference distance stored in EEPROM.
- Make sure the tank is empty.
- Set the mode switch to AUTO.
- Press the SET button once — the current sensor distance is saved as the empty-tank reference (
EEPROMaddress 0).
| Condition | Action |
|---|---|
| Level < 30% | Pump turns ON |
| Level ≥ 95% | Pump turns OFF |
- Pressing SET toggles the pump ON/OFF directly.
- A safety cutoff still forces the pump OFF if the level reaches ≥ 99%, so manual mode can't overflow the tank.
- Line 1:
WATER LEVEL: <xx>% - Line 2:
PUMP:<ON/OFF> <AUTO/MANUAL>
- Verified clean: 0 DRC and 0 ERC violations.
- The Arduino Uno 3D model does not render in the KiCad 3D viewer for the
Arduino_UNO_R3footprint on this system, so the 3D preview/renders are shown without the Uno model in place. This is a visualization-only gap — the footprint, pin mapping, and board layout underneath it are unaffected.
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- Add the status LED from the Wokwi simulation to the PCB as a physical pump-state indicator — it was dropped during the hardware conversion.
- Add a buzzer or audible alarm for low-level or overflow conditions.
- Resolve the missing Arduino Uno 3D model so the KiCad 3D preview renders the full assembly.
- Add WiFi or Bluetooth connectivity for remote level monitoring and pump control.
- Move calibration storage off raw EEPROM writes (e.g. wear-leveled storage) for longer write endurance.
- Add a float switch as a redundant safety backup to the ultrasonic sensor.
- Support multiple tank presets instead of a single calibrated reference value.
Srushti D Hebbar GitHub
This project is licensed under the MIT License. See the LICENSE file for the full license text.