FK904 Rain Detecting Alarm – Great School Project.
Here is a very easily constructed, economical kit which demonstrates the electrical conductivity of raindrops in a very practical manner.
The presence of water on the gold flashed detector grid forms part of an oscillator circuit which will drive both a speaker and a flashing LED.
These in turn will let you know when to bring the washing in or close windows. Can also be used to detect spillages and seepage from washing machines or refrigerators.
Power Supply: 9V DC
Price inc GST.