Vernier Software and Technology
Vernier Software & Technology

Water Alarm


A water alarm is an electronic device that sounds an alarm when its liquid sensor comes in contact with water. These devices are very useful in homes (especially basements) to protect against water damage and/or mold growth from leaky water pipes, broken plumbing fixtures, a backed-up sewer, or runoff from a heavy thunderstorm. In this activity, you will build a water alarm using a small piece of copper printed circuit (PC) board with a Vernier Analog Breadboard Cable to detect the presence of water, and a Vernier Digital Control Unit (DCU) to activate an alarm.

Design Objectives

  • Build a sensor to detect water
  • Use a Vernier Analog Breadboard Cable to connect the water sensor to the lab interface
  • Configure Logger Pro to detect a voltage change in the water sensor circuit and trigger a Vernier DCU
  • Use a Vernier DCU to activate a buzzer


Additional Materials

  • computer
  • USB cable
  • printed circuit board
  • breadboard
  • 6 VDC piezo buzzer
  • 10 kΩ resistor
  • jumper wires
  • soldering iron and solder

Download Project

Includes construction, software setup, calibration, and troubleshooting instructions.

Water Alarm

About Build Your Own Sensors

Build your own sensors (BYOS) activities give students the opportunity to build their own detectors and measurement devices. Students assemble an electronic circuit and use Logger Pro software to calibrate and test their sensor.

Find more Build Your Own Sensors »

Go to top