Is my just aquired Flow Meter Any good?

[Ls7corvete]

Originally Posted by 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?

Did you happen to get more than one? shipping is gonna turn a 70 cent IC into a 10$ IC if I have to ship just one.....

[TerraMex]

... and you could have asked for samples from several companies (web). they're pretty much free.
... and dont use fan headers from the motherboard. they have a nasty tendency to toast.
... and again, timer circuits for control purposes (lots out there, ref before).

[dsptech]

Did you happen to get more than one? shipping is gonna turn a 70 cent IC into a 10$ IC if I have to ship just one.....

I know, the $5 surcharge on top of shipping sucks.
I couldn't find the chip anywhere else so I just forked over the cash.
It's still a good deal overall considering the retail price of the flow sensor.
I did order two chips and I also bought the relay wich was another $5.
I bought a second chip to use in my pump.

... and again, timer circuits for control purposes (lots out there, ref before)

I know, I've looked at them but I'm a hack at best and most of that stuff is over my head.
I was hoping someone would make this easier with a little hand holding.
I'll study them some more and figure something out eventually.