Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
I've found this scheme for a water-level.
It has only visual alarm but with a NPN it's possible to connect a buzzer through pin12.
What I want to do is connect a pump that works like scheme:
ON - when level
The CD4066 is a Quad Bilateral Switch so you have 4 switches in a single package. If you read the data sheet and note the control lines you will understand how it works. The pin you mention is a control pin and one of 4 control pins used to turn the switches on and off. Pin 12 happens to be the control pin for switching the switch across pins 10 and 11. It is an input to the chip and not an output.
A problem I see with the circuit as posted is that there are no dimensions for the sensor? Most circuits like this are sort of hit/skip as they rely on the conductivity of the water (or media) they are sensing. The conductivity of water can vary considerably from geographical location to location. Rain water, well water and tap water all have different conductivity.
Can what you want to do be done? Maybe but you would use the 1/4 tank level to initiate a pump and the full level to stop the pump or the reverse if you are pumping the tank down when full. Remember if you start a pump you need to stop the pump and the same is true for a buzzer.
Read the data sheet and think about what you want to do. I won't say don't build the project but think about it a little.
I've found this scheme for a water-level.
It has only visual alarm but with a NPN it's possible to connect a buzzer through pin12.
What I want to do is connect a pump that works like scheme:
ON - when level
By on when level do you mean on to pump down or are your referring to the LED's or...?
I have just built a pump control that will work for you. I'm using it to pump down the water that is collecting under my house now from construction uphill...GRRRRRR!
What are the pump current and voltage requirements? Some slight modifications may be needed for your application.
This circuit will have problems with electrolytic corrosion on the probes as well as the problems of varying conductivity of the water.
I would not use this circuit for anything other than a temporary installation.
JimB
PS - I have visited Ravenna and Marina di Ravenna some years ago, nice places.
This circuit will have problems with electrolytic corrosion on the probes as well as the problems of varying conductivity of the water.
I would not use this circuit for anything other than a temporary installation.QUOTE]
Hi JimB,
That would be true with most materials. However, if stainless steel probes and hardware were used along with the proper sealing devices at the junctions I don't think there would be a problem for decades at minimum. I know this from my own experience as a journey electrician in my own community before I went back to school for my degree. The water handling systems I installed at schools, hospitals, processing plants and wastewater facilities are still functioning as designed.
Regarding the conductivity of the water medium, that is a matter of degree that can be overcome by the sensitivity of the circuit employed, and the isolation of the probes within and without the medium being sensed.
First off I guess it's not a good idea to sense water level using DC.
Besides possible lime deposit (increasing resistance) on the probes they will experience electrolytic processes resulting in dissolving probe material.
Better to use AC, which can be accomplished using symmetrical power for the probes.
Here is my idea of a four stage water level indicator with audible alarm at 1/4 tank level.
The outputs of 1/4 and 1/1 can be used to control a water pump using logic gates:
Logic 1/4 probe dry and 1/1 dry (what else?) -> pump on
logic 1/4 probe wet and 1/1 dry -> pump still on
logic 1/4 probe wet and 1/1 wet -> pump off
The circuit didn't fit on one sheet. Therefor it's split into sensor and alarm circuit.
I agree with JimB and Boncuk, you'll get corrosion even with stainless with a DC excited circuit. I've used a version of this: CD4093 Water Level Sensor (Detector) | Simple Circuit Diagram.
One-gate oscillator for the common probe, and a voltage-doubler/gate circuit for each level.
I totally agree with many users. Using DC for water level detection is a sure-fail solution on the long term. especially with the schematic i saw ( 180r is WAY too low for a series resistor). A pressure sensor will rely on water pressure rather than water conductivity and will not lead to elctrolysis based corrosion. Another solution i saw on a sump pump: An insulated tilt switch inside a float.
Anyway, If you decide to continue with your project, i suggest adding a transistor/MOSFET to amplify the current and a relay to provide isolation between your DC project and the mains.
Thank to all. I'm just arrived at home from work. After dinner I'll read all post.
For now thanks.
I'm very pleased JimB you've enjoined Ravenna (piadina, prosciutto, sangiovese wine,...)
to Reloadron & MRCecil
I've make an error typing how it works.
The pump is ON when level arrive at 3/4 tank and stop when arrive at 1/4.
to MRCecil
I've the same problem down my house.
to JimB & MRCecil
I know the corrosion problem but, like MRCecil said (using with stainless steel), I think it's over.
to Boncuk
Thanks for scheme. I'll study them but, I'm search something more simple.
If I don't find something else I'm going to use it. For now thanks.
to KMoffet
Thanks for schemes. Like I said to Boncuk, I'll study them.
to Boncuk & blueroomelectronics
Unfortunately the tank is open and not so large so solution with ball level is not good.
All it takes is two floodable balls (for weight considerations) on one string to activate a switch as you like. The switch has to be mounted well above the max water line if it carries mains voltage.
That method is accurate to 5mm water level.
The disadavantage is clear. You don't have any control over the circuit once it is calibrated and you won't have any information about the water level (algea or dirt on the balls might change the trip point) - meaning you can connect a light parallel with the pump to indicate it's running without knowing the actual water level.
I'd listen for the sound of it instead.
Whatever method you'll use I guess pressure measurement of the water column is the most precise and reliable way.
Since the compressed air is trapped in the pressure hose there will be no way for dirt or algea to enter it. Even if algea grow inside the pressure hose they won't close it air tight and leave a cavity big enough to sense water column pressure.
An annual inspection and cleaning (or replacement of the pressure hose) will take care of a long time reliable water level measurement without the need of recalibration.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
