Sensors: / Detectors: Water Sensors

Sensors / Detectors: Water / Moisture Sensors
#'s - S W - Z
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Last Updated on: Thursday, April 19, 2012 07:21 AM

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 Monitor
A while back I got a request from a company who needed a water seepage detector. They wanted a device that ran on 24vac and detected water using a fully isolated circuit. They wanted a circuit which switched off 24vac to a load when water was detected. The circuit below performs this function. By changing the phototransistor’s position in the detector circuit, the circuit logic can be changed so the 24vac source can be turned on when water was detected. This might be handy to activate a pump.....

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:

Water Activated Alarm - 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.... [from Andy Collison's website]

Water Activated Relay (Marin Lukas) - In his circuit Marin has used two transistors wired as a high gain compound pair. Transistor T1 may be a 2N2222A and T2 a BC108. The current gain will be the product of each transistors beta, which will be a minimum of 140 x 110 or 15400. The power supply used can be any voltage from 4.5 to 15 volts,.... [Designer is Marin Lukas]

Water Flowing in Pipe Indicator - 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.... [Designed by David A. Johnson]

Water Level Alarm - A circuit that offers visual indication of fluid level in a vessel, with a switchable audible alarm. Example uses would be to monitor the level of water in a bath or cold storage tank.… [Andy Collison's website]

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 Pump Hysteresis Circuit - A simple circuit to prevent a pump being damaged by being turned on and off rapidly (multiswitching)…. [REUK - Renewable Energy UK website]

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-leak detector uses 9V batteries - 05/27/10 EDN Design Ideas....The design uses Maxim Integrated Circuits ' MAX934, an ultra-low-power quad comparator with a built-in 1.2V reference. The chip uses about 6 μA. IC 1A , R 1 , and R 2 provide water-leakage detection. R 1 is the water probe, which can be two bare copper wires wrapped in a sponge. R 1 has high impedance when the sponge is dry, so IC 1A 's output stays high.... [Design Idea by Yongping Xia, Navcom Technology, Torrance, CA]

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

Water-Level Controller - ....

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 Seepage Monitor
A while back I got a request from a company who needed a water seepage detector. They wanted a device that ran on 24vac and detected water using a fully isolated circuit. They wanted a circuit which switched off 24vac to a load when water was detected. The circuit below performs this function. By changing the phototransistor’s position in the detector circuit, the circuit logic can be changed so the 24vac source can be turned on when water was detected. This might be handy to activate a pump.....[circuit designed by Dave Johnson, P.E.]

Water-level Sensing & Control - This is a simple but reliable circuit for your sump-pump, aquarium, boat, or whatever, but water only. Please be careful when working with 115Volt line voltage! Take every precaution to avoid electrical shock. Unplug the power before making changes or touching resistor R1. Murphy's Law applies to all of us!…. [Tony van Roon's circuit]

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