Is my just aquired Flow Meter Any good?

[dsptech]

I just won this on ebay.
I saw some pics of one in the forums which inspired to do a little search.
One hour later and I now have one.
http://cm.ebay.com/cm/ck/1065-29392-...tem=7588585011
I run a 1/2 loop and I think I should be ok.
The only thing that concerns me is that it runs on 24V .

Did I just waste my money or do I have something usable?
Can anybody who has one give me a clue how to wire it up and make it useful?

[bigben2k]

Dwyer makes those too, in plastic, and brass. Looks like you got a deluxe stainless steel one! (brass interior?!?)

I don't think that it'll be restrictive at all (9/16 inlet / outlet), so you ought to be very happy with it.

[dsptech]

That's great!
As long as it works I seem to have gotton an incredible deal.
What can I wire it up to to monitor it's signal?
I guess I also have to figure out how to feed it 24V and then I can wire it to a 12v relay.
Can't wait to get it now.

[billbartuska]

Originally Posted by dsptech

Did I just waste my money or do I have something usable?
Can anybody who has one give me a clue how to wire it up and make it useful?

Uh, ...It's a flow sensor, not a flow meter. If you had a 24V power supply, if had some kind of a delay switch, if you are handy with custom installations...then you could prolly get it to work as a no-flow emergency shutdown device. But your bios prolly does that.

[BillA]

as bb said, does not seem to have a pulsed output
of course you could put it in a panel with some leds and watch it spin for bling

[dsptech]

Uh, ...It's a flow sensor, not a flow meter

Excuse my ignorance geeze, what an idiot I am.
I got so excited when I found the auction I never bothered to read all the details.
Buy now, figure out later.

Well I guess I still could use it as a "no-flow emergency shutdown device" and exploit it's "Bling" value.
Just wish it was 12V now.
Maybe I can mod it and add a Hall Effect Sensor.
Guess I'll just have to wait till it gets here.

Thanks guys.

[BillA]

idiot is a bit harsh, I've bought many items that "seemed like a good idea at the time"
just another lesson, and you can resell it easily too

[TerraMex]

having an emergency shutdown is very useful.
nothing wrong with that. suggest to check manufacturers site to see if you can replace the body, they have, at least seem, to have others.

[ProHandyman]

Originally Posted by dsptech

Well I guess I still could use it as a "no-flow emergency shutdown device" and exploit it's "Bling" value.
Just wish it was 12V now.
Maybe I can mod it and add a Hall Effect Sensor.
Guess I'll just have to wait till it gets here.

I agree... if you keep... definitely bling... and I can't imagine that you couldn't find a comparable 12v relay for "switching".

[bigben2k]

I'd keep it. Both bling and usefull. The question left is, what do you want your PC to do, if there's no flow, then how are you going to make it do that?

You could tap it into the power_good line of the PSU, but it'll shut down the PC without warning.

You could simulate a tach signal (sample circuit has been posted here before) and feed it through the CPU fan header, causing a softer shutdown.

Many options.

[BillA]

latching relay on the off button

[TerraMex]

i would do both. (rimshot)
you can feed a circuit that cuts a pre defined tach signal to the motherboard (thus thinking the fan is kaput), and simultaneosly activate a timer circuit that cuts the psu power in 5min. All simple and feasable.
No such thing as too much redundancy .

[dsptech]

That's sounds exactly what I'd like to do.
I think simulating a tach signal ranks highest of the two.
Implementing a timer based shut-down circuit for redundancy could follow depending on difficulty.

I'll have to find that circuit that was floating around.
I already have some hall effect sensors waiting to be used.
I can't wait to see the insides of this thing.

[TerraMex]

you just need two 555 based circuits, and three relays.
nothing fancy.

555 circuits for dummies:

http://www.uoguelph.ca/~antoon/gadgets/555/555.html

middle of the page has an oscillator circuit (google for more), which provides a tach signal to the mobo. also has how to make a switching operation with a delay, to a relay.

http://home.cogeco.ca/~rpaisley4/LM555.html
more circuits.

[dsptech]

So cool.
You guys are the greatest!
I'll keep this thread updated as I go along.

[billbartuska]

Originally Posted by bigben2k

I'd keep it. Both bling and usefull. The question left is, what do you want your PC to do, if there's no flow, then how are you going to make it do that?

You could tap it into the power_good line of the PSU, but it'll shut down the PC without warning.

You could simulate a tach signal (sample circuit has been posted here before) and feed it through the CPU fan header, causing a softer shutdown.

Many options.

Don't forget, you have to get the computer to start too.
No flow, no start! You need some kind of delay to get the computer started w/o flow, but what happens when there is a power outage or worse a monentary glitch. If the delay doesn't reset, the pc may start w/o flow.

[TerraMex]

if he does it properly, the circuit would kick in if no flow is detected, after boot.
the computer can live for 5min without flow .

[dsptech]

The same guy I bought my sensor from on ebay has another one listed.
http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWA:IT

He probably has a few of them.
If anyone else is looking for one, here's your chance to get one cheap.
Starting bid is $4.99 with less than two days left on a 7 day auction.
I'm still waiting on mine.
Hopefully Monday.

[dsptech]

I finally got this taken apart.
The star wheel has magnets embedded in each point.
There is a sensor inserted in the top of the housing to pick up the rotation.
I'm not sure what type of sensor it is, maybe a Hall Effect?
If it is, then it should be possible to wire it for RPM reading?

There are two chips on the board.
One is a Fairchild CD4538BC, Dual Precision Monostable.
The other is a Onsemi MC14013B Dual Type D Flip-Flop.
I have no clue about these.

The relay is a Aromat (now owned by Panasonic) DF2E-DC24V DF Series Dual Coil DPDT 24V 300mA Latching Relay.
Maybe this can be replaced with a 12V relay?

A potentiometer was glued to the top of the relay.
It is used to set the the trigger point for the relay.
From what I understand, if the rotional speed drops below the set point the relay will be triggered.
This seems to suggest that the sensor can determine rotational speeds, not just that it's turning.

What I'd like to do is modify the circuit to give out rpm speeds to be connected to a fan header.
Use the onboard relay to shutdown the system if the rotation stops due to the pump failing and the systems fails to shut itself off.
Maybe set off an warning alarm also.

I need the real tech gurus to help me with the electronics side of things.
I can solder, etch my own boards but I'm not an engineer.

Anybody feel like helping me out?

Here are the data sheets for the chips and relay...
http://home.earthlink.net/~dsptech1/rfs-2500/1462.pdf
http://home.earthlink.net/~dsptech1/...0/CD4538BC.pdf
http://home.earthlink.net/~dsptech1/...0/MC14013B.pdf

Data sheets for the RFS-2500...
http://home.earthlink.net/~dsptech1/rfs-2500/RFS.pdf
http://home.earthlink.net/~dsptech1/...0/RFS-2500.pdf

Some images....
http://home.earthlink.net/~dsptech1/rfs-2500/Board.JPG
http://home.earthlink.net/~dsptech1/rfs-2500/Board1.JPG
http://home.earthlink.net/~dsptech1/rfs-2500/Sensor.JPG
http://home.earthlink.net/~dsptech1/...r-location.JPG

[TerraMex]

What I'd like to do is modify the circuit to give out rpm speeds to be connected to a fan header.

i had logical circuits 7 years ago .
but i think the circuit doesnt work as you think.

My reading of it (looking at the circuit) is that there's a timer circuit with a variable step (monostable) that maintains a down (or high, can work both ways) signal as long as the capacitor doesn't discharge completly. When you ajust the potentiometer , it ajusts the step. What happens is if the flow drops, the time between bursts from the hall sensor becomes larger than the time needed for the step to remain down, and it goes up, and it changes state on the flip-flop, just like a shmitt trigger circuit (i think). However it must have a small histerisis or it would be going on/off all the time on the designated setpoint.

Anyway, if you have the sensor itself, you can build a circuit to read the hall signal, there's a few circuits out there, you don't actually need the flowswitch circuit. Try searching for hall effect circuits (and reading).
I don't know any, but i'll see if i can find out.
In last resort, try using a fan circuit, they have a hall sensor and they already have a tach output -> desolder the hall from the fan, connect wires from flowsensor. But be careful because of voltage considerations, i dont know if they are interchangeable.
(remember this? http://www.overclockers.com/tips642/ )
I could be wrong.

[Ls7corvete]

I just grabbed one of these as well, I have a sacrificed TT fan that im thinking of hooking up to this thing.

Is there any markings on the hall sensor? I cant seem to get mine out.

If all else fails, the hall sensor from the fan may be able to pick up the signal from the sensor correct?

[dsptech]

I've ripped apart around six different fans and have yet to find one with a 3 pin hal sensor.
Mine all have 4 pin ICs or more.

Anyone know of a fan model with a hal sensor?

[Ls7corvete]

Originally Posted by dsptech

I've ripped apart around six different fans and have yet to find one with a 3 pin hal sensor.
Mine all have 4 pin ICs or more.

Anyone know of a fan model with a hal sensor?

I pulled apart a tt 120mm and found a small 3 pin hall sensor.

[dsptech]

I made some progress on this.
It can be powered from +12V.
I ordered a DF2E-DC12V relay from Digikey to replace the 24V one.
It is a direct replacement.
I put it in and it worked just fine.
The other ICs have a wide voltage range so no problem there.

The way this thing works is like this...
While the water is flowing the sensor detectes the wheel spinning.
While it is spinning the LED stays lit and the relay latches.
If it stops spinning the LED goes out and the relay releases.

Now I need to figure out a circuit to have the relay to do something useful.

I also ordered a ULN2003D Darlington Array.
This chip is similar to the ULN2803 used here...
http://forums.procooling.com/vbb/showthread.php?t=10969

The difference is it has 7 outputs and is way smaller and will fit inside the body nicley.
I'm going to tap into the sensor to see if I can get RPM output.
Not sure if I should power the whole thing from a fan header or use the fan supply just for the rpm circuit.
I think that the relay will draw too much from a fan header.
Maybe someone could chime in on this?

[AngryAlpaca]

Don't you just hate how this question always comes up right after we purchase something? It's an awful system, really.