Sensors: / Detectors: Water Sensors

Sensors / Detectors: Water / Moisture Sensors
Sensors / Detectors -- Main Page
Last Updated on: Friday, March 12, 2010 12:07 PM

Circuits designed by Dave Johnson, P.E. :

Electrodeless Water Level Monitor
This system operates much like a classic float switch but without any moving parts. The illustration shows how a system using two copper coils sealed inside a plastic pipe, can detect the level of water outside the pipe. Whenever the water level is lower than the upper coil, no signal is coupled between the coils. Once calibrated, this technique might also work on the outside of a plastic water tank. (added 7/06)

Water Flowing in Pipe Indicator -- July 6, 2009
The vibrations associated with water flowing through a pipe are picked up by an inexpensive piezoelectric wafer. The signal from the wafer is first boosted by a micropower transistor amplifier and then fed to an ultra low power voltage comparator. When the vibration signal has sufficient amplitude, a FET transistor switch is activated. Drawing only 6uA, the whole circuit is powered by a lithium coin battery, which should power the circuit for many years....

WATER SEEPAGE ALARM
This simple circuit sounds a beeper when its electrodes detect water. A single 1.5v N cell powers it. A small 1.5v button battery will also work.

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

12 Volt Toilet Tank Refiller - (circuit / design added 8/03)

AN1013: Gas and Water Metering with the PIC16F91X Family - Microchip Application Note Published 20-Jan-06 (app note added 2/06)

Christmas Tree (or other plant) Moisture Monitor - Originally intended to monitor the moisture in a potted plant, this moisture monitor really shines as a Christmas tree stand water level monitor! A fresh Christmas tree drinks water an annoying rate and bending down under the decoration-laden branches ...(electronic design added 7/08)

Gas and Water Metering with the PIC16F91X Family - Microchip Application Note Published 20-Jan-06 (app note added 2/06)

Hot Water Tank Indicator - (circuit / design added 8/03)

One wire bus powers water level sensor - 02/15/00 EDN-Design Ideas: remotely monitor the level of liquid water in a vessel such as a swimming pool.....(design idea added 2/06)

Plant Moisture Meter (Randy Linscott) - Stick the metal probes into a freshly watered plant and adjust R5 for a mid-scale meter deflection. The meter will monitor the soil wetness and the meter will indicate whether it is to moist or to dry. This circuit uses a dual power supply which could be created by two 9 volt batteries….(added 05/08)

Plant Moisture Monitor - (circuit / design added 8/03)

Plant Power - Following a hunch, the author discovered (or re-discovered?) that all plants carry an electric charge relative to the ground. This charge is more or less constant regardless of the size of the plant, a kind of "background voltage" in nature....(electronic design added 6/07)

Pot Plant Power - All plants carry an electric charge relative to the ground. This charge is more or less constant regardless of the size of the plant a kind of background voltage" in nature. This electric charge suffuses the entire plant, from its roots to its leaves and fruit. It was measured between a chrome-plated pin inserted into the plant .... (added 6/03)

Pot plant water tester - (electronic circuit added 10/05)

Rain Alarm - This circuit gives out an alarm when its sensor is wetted by water. A 555 astable multivibrator is used here which gives a tone of about 1kHz upon detecting water. The sensor when wetted by water completes the circuit and makes the 555 oscillate at about 1kHz.….(design added 03/08)

Rain Detector (Aaron Cake) - This circuit uses a sensor made of a small piece of etched PC board and a simple SCR circuit to detect rain and sound a buzzer. The SCR could also be used to activate a relay, turn on a lamp, or send a signal to a security system. (circuit / design added 8/03)

Shower Stopper - (circuit / design added 8/03)

Water Activated Relay - The circuit uses a 555 timer wired as an astable oscillator and powered by the emitter current of the BC109C. Under dry conditions, the transistor will have no bias current and be fully off. However as the probes get wet the transistor will conduct and sounding the alarm. An On/Off switch is provided and remember to use a non-reactive metal.....(electronic schematic / circuit added 4/02)

Water Level Alarm (Andy Collison) - (electronic schematic / circuit added 4/02)

Water Level Control/Monitor - A simple way to control the level of any liquid in any container. (electronic schematic added 05/04)

Water Level Reference Design - The Water Level Reference design continuously monitors water level and water flow using the temperature compensated MPXM2010GS pressure sensor in the low cost MPAK package, a dual op–amp, and the MC68HC908QT4, 8–pin microcontroller. This system uses very few components, reducing the overall system cost. (app note added 3/05)

Water Seepage Alarm - This simple circuit sounds a beeper when its electrodes detect water. It is powered by a single 1.5v N cell. A small 1.5v button battery will also work. ….(designed by David A. Johnson)

Water-level Alert - Beeper or flashing LED alert. (electronic design added 6/07)

Water-Level Controller - (electronic Circuit / Schematic added 10/04)

Water-level Indicator - The whole project was developed on a friend's request. Its purpose was to remotely monitor the water-level in a metal tank located in the attic by means of a very simple control unit placed in the kitchen, some floors below. ….(electronic schematic added 11/08)

Water-level Sensing and Control - (Tony van Roon's circuit / design added 8/03)