Send Limit Alerts while humidity<30%

Hey! It's been about 2 months i'm using NodeRED
i'm about to use FRED for my small project
The project is to monitor soil humidity.
I didn't know how to sends alerts in notification dashboard when the humidity <30%

Does anyone know how to create the flow?
I'm using mqtt protocol with NodeMCU V3 and YL-69 moisture sensor

Thank you!!

You want to send alerts to ?
The dashboard won't send alerts (although you could somehow create it) unless you mean the notification in the dashboard itself.

You already have mqtt, so create the alert in the node-red editor with a flow.

do you know the flow configuration for creating an alert in the editor?

How do you want to receive the alert? email ? Telegram ? In the dashboard ?
It would be nice if you could explain what you want to achieve and what your flow looks like.

Take a look at the cookbook, examples in there such as this should get you started

Here's a link to a soil moisture project that some of my IoT students tackled last September.
It might give you some ideas to get you started.

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In its simplest form, you want to create and "alert" when a value is > a "limit" right?

So add a switch node and set the comparison type to > and the value to 30 (or whatever equates to 30%) then feed that to a switch node that sets payload to a suitable string e.g. "humidity is greater than 30%" and feed that to a notification node.

In basic terms...
Sensor (MQTT input) :arrow_forward: switch node (test the value) :arrow_forward: change node (set payload to your notification message) :arrow_forward: notification node (so that you get an alert)

Notes: this is pretty useless to be fair. You'd be better off sending an email or telegram so you don't have to sit with your eyes pinned to a dashboard.

Better still, you would feed this "alarm" to a system that controlls the humidity (perhaps stop water flow or an air conditioner to reduce humidity) and have the system look after itself :sunglasses: