Hall Effect Sensor connected to GPIO pins - How can I could pulses per minute?

Hi all,

I have a hall effect sensor connected to my Pi GPIO pins and the pulses are coming in fine. It's a water flow meter connected to an irrigation system for a community.

However, I have no idea as to how best (or even how full stop) to count the pulses per minute (to monitor the flow). My main aim is to alert if a pipe is leaking but I'd like to also monitor usage.

Last year, we had a pipe which leaked for over a month and cost us €15k in water charges - which we had no choice but to pay !!!

The node node-red-contrib-msg-speed can tell you how many messages arrived in a given period.

A flow like this might work to display usage and detect leaks:


Hi again,

I am monitoring the flow of water to a irrigation system for an apartments complex. I have used the MSG-SPEED node as suggested.

I have this working somewhat nicely but I have a small issue. The count appears to be HIGHER when my flow rate is lower
The high peak is Zone 7 which used about 70 litres per minute, whereas the starting peak to 100 is Zone 1 which used about 81 litres per minute.

My main aim is twofold - A) mainly to monitor that something has not failed and that we don't have water escaping when we should not and B) to monitor if a Zone is using more water than expected indicating a burst pipe or broken sprinkler valve.

I resolved my issue by setting "Debounce" to ZERO

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