Liquid Flow detection sensor

Just wondering if anyone has seen or come across a 1 way flow direction sensor. I've found hall effect flow sensors but I'm really just looking for a sensor that gives me a relay closure or logic signal if there is flow in the positive direction and a logic low of relay open if the flow has stopped or reversed. I've found this but it really is overkill and a lot more software to go get it to work for my needs http://www.seeedstudio.com/depot/g12-water-flow-sensor-p-635.html

Thank you in advance.

I am using the sensor you linked. It works very well and it's very easy to use. Using interrupt you do not have to write a lot of code. the only problem is that it can only detect flow going in one direction or if the system is stopped. But a quick way to solve your problem is adopting 2 sensor like that one (the're also cheap). Put them in serial mirrored connection so une will detect one sense flow, the oder the opposite one. After attach the to two INT pin, for example int 0 and 1.

Cantore do you have example code you can post?

I have worked with - http://www.conrad.de/ce/de/product/150189/DFM-MESSING-ANSCHLUSS-R-1 - expensive but worked like a charm.

It gave a nice pulse which I counted in an IRQ routine (RISING edge only) => 45 pulses per liter (or ~166 per gallon). == steps of 22 milliLiter

I did not need it but you could do an IRQ on CHANGE to get a resolution that's twice as high in theory (see my foottext).

Rob

stealthtransam:
Cantore do you have example code you can post?

I have sent you an example via mail. Pay attention you must connect the yellow wire to an input pin supporting interrupt, for example pin 2.