How to measure water flowing from a washing machine pump?

[Brad_805]

Hi all
Am trying to find a way to measure the vol/time flow of water from the washing machine. Is there an electronic component that can be used like a coil of copper wire over the tube and the do something with a microcontroller perhaps and it figures out much flow? by electromagnetic measurement?

 

[davenn]

Hi there
Welcome to PF

Is there an electronic component that can be used like a coil of copper wire over the tube and the do something with a microcontroller perhaps and it figures out much flow? by electromagnetic measurement?

water is neither magnetic nor electromagnetic
there's zillions of flowmeters available ...

https://www.bing.com/search?q=water+flow+meter+suppliers&src=IE-SearchBox&FORM=IENTSRDave

 

[Bystander]

there's zillions of flowmeters available ...

Dynamic range is another matter; admittedly I've not been all that active recently, but "flow-rates" have, in my past experience, seldom exceeded 10 percent accuracy outside a very limited dynamic range, single O(m).

 

[PeterDonis]

Moderator's note: Thread level changed to "I".

 

[Brad_805]

I want to make it from parts, cost maybe $25.00 I know there are flow meters for sale. wanted to make it from scratch

 

[pedro the swift]

Stopwatch and a bucket. Thats less than $25.

 

[Brad_805]

Stopwatch and a bucket. Thats less than $25.

So the requirement here is to have an electronic sensor and microcontroller that measures the instantaneous d/dt flow, sending out flow measurements with a time stamp. The real question is what mechanism is used in this industry to measure water flow? what electronic apparatus, device, sensor, circuit or thing would be put inline if needed or around the hose or at the point where water exits the hose to measure the realtime flow. Or if there is no way known by science to measure water flow electronically? then that's the answer.

 

[anorlunda]

https://en.wikipedia.org/wiki/Ultrasonic_flow_meter

It sounds like you are seeking something like the ultrasonic flow meter. They exist, but I believe it will cost much more than $25 with all the supporting electronics. Probably closer to $25000.

 

[Dullard]

There are several ways to measure your water flow. These include:

a 'Mag Meter' (requires that the water be slightly conductive) -these are commercially available - I've never 'rolled my own.'

A dP device - insert an orifice and measure the flow-related pressure drop - this is a pretty standard approach.

A thermal device - measure the water temp and measure the power required to maintain a heated probe at a slightly higher temp. This is a common way to precisely measure gas flow - it will work with water.

I don't think you'll get near $25 with any of them, unless you have a pretty good junk box and mad skills.

 

[Nugatory]

Am trying to find a way to measure the vol/time flow of water from the washing machine.

You will likely get better answers if you tell us more about what problem you're actually trying to solve. By far the most cost-effective and practical way of measuring the flow from a washing machine is a bucket and a stopwatch... but if that answer isn't what you looking for, then there must be other constraint as well.

Are you by any chance trying to adapt a washing machine motor for some purpose other than washing clothes? If so, tell us what you're trying to do and see what the collective experience of this group can contribute.

 

[Brad_805]

There are several ways to measure your water flow. These include:

a 'Mag Meter' (requires that the water be slightly conductive) -these are commercially available - I've never 'rolled my own.'

A dP device - insert an orifice and measure the flow-related pressure drop - this is a pretty standard approach.

A thermal device - measure the water temp and measure the power required to maintain a heated probe at a slightly higher temp. This is a common way to precisely measure gas flow - it will work with water.

I don't think you'll get near $25 with any of them, unless you have a pretty good junk box and mad skills.

Well the dp device sensing pressure drop may be the best to start with. problem is that in the washer, water flow is say 100% then it drops and tapers off so thermal may not work on the partial flow. Used to have a lot in the junk boxes. people called me a hoarder? I just needed a larger shop. Sadly I have next to no junk now.

 

[Brad_805]

You will likely get better answers if you tell us more about what problem you're actually trying to solve. By far the most cost-effective and practical way of measuring the flow from a washing machine is a bucket and a stopwatch... but if that answer isn't what you looking for, then there must be other constraint as well.

Are you by any chance trying to adapt a washing machine motor for some purpose other than washing clothes? If so, tell us what you're trying to do and see what the collective experience of this group can contribute.

Well... I don't know how to explain it better, If I said what its for? then the discussion would move away from trying to measure water flow, it is not some hack of the washing machine, its a standard washer.

having an electronic sensor thing that sends digitized flow info 24/7 I think the bucket idea may not be ideal. to calibrate it perhaps? sure. I wanted to know the mechanisms for sensing water flow thru a pipe, what reacts with the water? if a coil was placed over the pipe and the coil was part of a tank circuit with some freq range, and water passes in the pipe would the freq change?

 

[jbriggs444]

If I said what its for? then the discussion would move away from trying to measure water flow

The problem is that unless we know what it is for, we do not know what cost/benefit tradeoffs are relevant. One cannot choose a good design unless one knows the constraints under which one is operating and the design goals one is working to optimize.

Just to add another possibility... flexible tubing and a spring scale to measure centrifugal force around a curve in the tube. Of course, good calibration would probably need to compensate for pressure in the line as well.

 

[Bystander]

https://en.wikipedia.org/wiki/Mass_flow_meter

 

[Brad_805]

Well I mean its a microcontroller and then some wires going to some kind of sensor, or some kind of sensor unit that's powered and all it does is quantify flow. Is there nothing water reacts to? magnetic field zero, charge zero are there no fundamental forces known that water reacts to? yes the spring idea is perhaps very workable, how much deflection happens to some plate as the hose comes up and bends down into the drain pipe, add a device the water hose plugs into, water hits a plastic flap held shut by a spring. water dripping onto the flap would push it some amount, then the trick is to find the conversion sensor to measure that flap

 

[davenn]

Is there nothing water reacts to? magnetic field zero, charge zero are there no fundamental forces known that water reacts to?

as far as I'm aware, nothing in a way that would help you measure the flow

building your own for $25 probably isn't going to happen

What is your electronics experience ( be honest, don't exaggerate) ?
You will have to buy the flow sensor and that could easily cost more than $25 on its own
( I haven't specifically priced them, have you ??) let alone the rest of the electronics, the
time programming your micro to work with the data from the sensor

I gave you a whole page of links

 

[Asymptotic]

Another consideration is you propose to measure gray water flow rate from the washer whih will be loaded with dirt, fibers and other debris, and tend to clog certain types of flow meters.

 

[russ_watters]

So the requirement here is to have an electronic sensor and microcontroller that measures the instantaneous d/dt flow, sending out flow measurements with a time stamp.

How often? And are you sure you mean instantaneous and not cumulative?

 

[Brad_805]

What is your electronics experience ( be honest, don't exaggerate) ?

extensive. about 45 years, a lot of school, a lot of design, test. Worked with and owned tv repair shops, fixed tube-transistor and newer, a lot of electronics work on a lot of things for many companies over the decades. still learning, always new things I didnt know.

You will have to buy the flow sensor and that could easily cost more than $25 on its own

--No, I want to make the flow sensor, there has to be some way.

( I haven't specifically priced them, have you ??) let alone the rest of the electronics, the
time programming your micro to work with the data from the sensor

--I also do programming, RT embedded is fun.

let me look for that list. One of my problems today is that I had to give up just about ALL of my junk, things, tools, spools of wire large/small, connectors, circuits, chips, passives... a small fortune in parts. don't have access to my stereo scope nor hot air soldering tool, or all the automotive tools. most of those are gone. so instead of just try something? I don't have anything to work with, its a very depressing feeling, literally. Then being employed part time, there isn't a budget to buy anything

 

[Brad_805]

How often? And are you sure you mean instantaneous and not cumulative?

Need both but need to rate d/dt and then the total, but would summarize

 

[Brad_805]

Another consideration is you propose to measure gray water flow rate from the washer whih will be loaded with dirt, fibers and other debris, and tend to clog certain types of flow meters.

Thats a great point, its gray water. so a plastic flap being deflected over a spring and then a 3 axis resolver chip glued to the flap, they cost about $1 glued to the hinge. then map out xyz and make a correction factor chart, and the microcontroller would calculate based on what it gets from that resolver chip. probably a good way to go

 

[russ_watters]

Need both but need to rate d/dt and then the total, but would summarize

How often?

 

[Brad_805]

How often?

I think a plastic flap with a 3d resolver chip on the hinge fed to the microcontroller would work, 100 samples/sec should work? then calibrate with known volumes of water, etc

 

[JT Smith]

You can buy a flow meter for $10 or less that will work for you, provided you're not looking for high accuracy. But since you don't want to buy one you could copy that design. If you do an internet search you'll find an example of someone who did that. I turned up two different inexpensive build-your-own-flowmeter designs in five minutes of googling.

 

[Brad_805]

You can buy a flow meter for $10 or less that will work for you, provided you're not looking for high accuracy. But since you don't want to buy one you could copy that design. If you do an internet search you'll find an example of someone who did that. I turned up two different inexpensive build-your-own-flowmeter designs in five minutes of googling.

Ok I found some ideas but one of the purposes of asking here was to ask about the fundamental physical properties of water flow measurement; what reacts with water, or actually gray water. Maybe gray water is more reactive? will gray soap rinse water store an electric charge? but that may not be good,

 

[russ_watters]

I think a plastic flap with a 3d resolver chip on the hinge fed to the microcontroller would work, 100 samples/sec should work? then calibrate with known volumes of water, etc

That's a really, really high sampling rate.

 

[anorlunda]

Ok I found some ideas but one of the purposes of asking here was to ask about the fundamental physical properties of water flow measurement; what reacts with water, or actually gray water.

You're all over the place. It is one thing to tinker with a DIY flow measurement. But if you want to understand science, it takes serious study. Asking questions on the Internet is a very poor learning strategy.

So please decide. Would you like suggestions on a DIY project, or suggestions on a course of studies?

 

[Brad_805]

You're all over the place. It is one thing to tinker with a DIY flow measurement. But if you want to understand science, it takes serious study. Asking questions on the Internet is a very poor learning strategy.

So please decide. Would you like suggestions on a DIY project, or suggestions on a course of studies?

Seriously? you can't follow what I said, and if you read all the posts, came up with an impossible answer solving a water flow problem for cheap? I chose a physics group that has educated people responding in a peer fashion; if one disagrees? they can correct the other. I want to learn far more about science, if not for this need to earn money for rent, bills and food my entire existence would be r/d.

By all means! I want to study and learn more, but at no time have I been "all over the place". In a couple days was able to come up with a concept to measure flow that likely has good accuracy, its now time to prototype and test the mechanisms

If you have suggestions on studying? I am interested.

 

[Brad_805]

That's a really, really high sampling rate.

How about 50 samples/sec?

 

[anorlunda]

If you have suggestions on studying? I am interested.

I'm not trying to be pedantic. I don't know your background. Many people start with Wikipedia.
https://en.wikipedia.org/wiki/Fluid_dynamics
Perhaps that's not relevant to your interest.

But I stand by what I said, that asking questions and reading short answers is a very poor strategy for learning. That is why we have textbooks. Students get to ask questions after reading the book and listening to the lectures.