Overhead Water Tank Overflow Alert System
The full build guide for this water overflow alarm — the steps below follow the project setup in the same order.
What you need before starting
- Sound Alarm: Active Buzzer
- Power Source: Old 5V Mobile Charger / Adapter (with cut and stripped wires)
- Water Probe Leads: Exposed positive and negative wire pair (running up into the overhead water tank)
- Power Cable: 2-Pin Mains Plug Cable
- Enclosure & Wire Accessories: Small Plastic Project Box, Wire Connectors, Electrical Insulation Tape, and Water Container (for testing)
The full build guide for this water overflow alarm — the steps below follow the project setup in the same order.
Prepare the 5V power supply
Take an old 5V mobile phone charger adapter and cut off the output connector to expose the internal positive (red) and negative (black) power wires.
Connect the active buzzer and water probe leads
Connect the positive lead of the 5V charger directly to one wire of the long water probe lead that extends up into the top level of the overhead water tank. Connect the second wire of the water probe lead to the positive terminal of the active buzzer, and join the negative terminal of the buzzer back to the negative wire of the 5V charger.
Enclose the alarm system
House the 5V charger module, buzzer, and terminal connections safely inside a small plastic project enclosure box, extending the 2-pin power plug out for wall mounting and the long probe wires out to the tank.
Install probe leads in the overhead tank
Run the insulated two-conductor probe wire up to the overhead water tank. Fix the two stripped wire tips inside the tank near the top rim, ensuring they are spaced slightly apart so they do not touch each other directly.
Test the overflow alarm system
Plug the system into a wall power socket. Fill a test container with water and submerge the two exposed wire tips. When water touches both contacts simultaneously, it completes the low-voltage circuit and activates the loud buzzer to signal that the tank is full.
If something does not work
Buzzer does not sound when submerged: Check the polarity of the buzzer connections and ensure the 5V charger is supplying power.
Alarm triggers randomly or constantly: Ensure the two probe tips in the tank are separated and not touching each other or metallic tank surfaces directly.
Buzzer sound is faint: Clean any corrosion or mineral buildup off the exposed copper wire tips submerged inside the water tank.