Flow Sensor?

[Archades]

Hi. I was wondering if the OSPI + mobile app had support for the flow sensors? Couldn’t find a way to search on the site so I apologize if this has been asked before.

[Ray]

There is a recent post here:
https://opensprinkler.com/forums/topic/flow-sensor-working/
about getting flow sensor to work with the microcontroller-based OS. I know that RPi supports interrupt pins, so the same approach should work for OSPi, but it’s yet to be tested.

[Archades]

Ok, Thanks.

I am looking around for flow sensors at the moment. What kind of pulse rate should I be looking for to avoid the issue you describe with regard to the interrupt pin?

[Ray]

That really depends on RPi — what’s the highest frequency of interrupt its pins can handle. I assume it should handle at least a few kilo-hertz.

[Archades]

A quick google seems to suggest around 5-20mhz for GPIO on the rpi, not sure about interupts.

I am looking at a flow sensor here in Australia, here are the specs

Specifications
Measurement range              1.0 – 60 LPM
Calibration      Flow(LPM)      = f(H2) x
23.8 (should be a divide by bar above the 23.8 so it looks like f(H2) x OVER 23.8)
Repeatability   <= 1%
Accuracy                                   <=2.5% of FULL SCALE
Protection class                       IP65
Max uid temperature            60  C
Max ambient temp range      0  C – +60 C
Max uid pressure                    1.5 Mpa
Operating voltage                    +5V
Output                                        frequency square wave

I’m unsure of what the (h2) and x is in the calibration. Would something like this work ok though?

[Author]

Posts