Hello; I'm testing this project on my Raspberry Pi 3B: https://pexpeppers.com/blogs/pepper-growing/diy-greenhouse-control
It's thanks to this project that I discovered the power of Node-RED. This project works very well, but I need to modify a few things for it to work on my greenhouse project. My setup uses opening windows controlled by switches that only need a pulse (push button). I want the DHT22 to send this pulse. But I can't configure the project I'm using to send a pulse instead of the continuous operating time (like a fan). I've been trying to fix this myself for several days, but I lack the necessary knowledge. Could you help me? Thank you.
How are you controlling the DHT? Can't you just send ON followed by OFF a fraction of a second later?
You can do that with a Trigger node.
Thanks for your super quick reply 
I haven't been able to get this configuration working with the "trigger" node. I'm a beginner and I still need to improve. Regarding the "trigger" node, when I use it, it remains constantly active because the temperature stays at 1.
There is also a filter node you can set to pass once until the value changes
[edit] not sure this is a hardware problem, seems more to be general
If you configure a Trigger node like this
Then every time you send it a message it will send 1 then 250ms later it will send 0. Is it something like that that you need to do?
I've already tried that solution, but it doesn't stop the control contactor. Because the temperature continues to send the signal, the control contactor remains engaged all the time.
So under what conditions do you want to send the pulse?
I want the signal to be sent for about 2 seconds when the temperature exceeds the programmed threshold. And that's what I'm having trouble with. I don't know which nodes to use for this.
Try this
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Thanks for your help. I'll test your solution in a few days. I'll keep you posted.
