Max minus min value after a quantity of msg.payload (people counter)

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1

Hello.
We have a people counter that sends 4 messages every 4 hours with an increasing number each time.
I've made a flow that takes, after four messages, the largest value minus the smallest between two points in time: From the last time it updated to the current time.

The result is a payload that contains three elements:
1 Number of passages (payload.number)
2 Current time (payload.now)
3 Last time (payload.last)

The very first message will get an error because the latest time doesn't exist yet...

I'm clearly not a code expert and most of this is copy-paste from others, which certainly shows. But I hope someone can use this for their projects!

You need to install the date/time formatter “node-red-contrib-moment”.

FlowC
FlowC1104Ă—179 43.2 KB

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2

Confused here is that 1 msg every 4 hours or is that 4 message every 4 hours, Can we see a debug of these 4 messages to be sure.

Your flow looks a little over complicated.
may be this example will help

1 message every 4 hours.

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4 messages every 4 hours

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1 Like
3

Tanks a lot!
Because my lack of knowledge of code I could never have done that :slight_smile:

The people counter is a Senlab PIR-Sensor that sends the payload every 4th hour.
So everytime it updates I get four payloads within one second and I don´t want to receive 4 mails.
I consider to even change the "Join-node" to wait for 12 msg, to receive one mail every 12 hours that tells me how many people have passed through the last 12 hours.

Or even better: one mail every 12 hours containing 12 lines where I can see passings each hour.
That can be my next learning project :slight_smile:

Thanks again for your improvement!