which unit of measurement to use for V_RAINRATE?

[garubi]

I have a simple rain detector sensor bulti using those cheap plate like this

It sends the usual "analog read" values from 0 to 1023 to Home assistant as V_RAINRATE

It's all good, I can read the values in HA but in the entity card's history they are shown as "discrete values":

I'd like to see them as a line, like the temperature is:

I think that the problem is that for the rain rate isn't set a unit of measurement.
What do you suggest I put in V_UNIT_PREFIX so to have the data displayed as a line?

[electrik]

In https://github.com/mysensors/MySensors/blob/master/core/MyMessage.h#L135
S_RAIN is used. As prefix I guess you can use whatever you want, eg mm/h

[skywatch]

You can't do what you want using that sensor - The sensor is just a simple on/off type sensor that tells you if the sensor plate is wet or not, it does not measure how much rain is falling. Even if you timed how long it was activated how would you know between heavy rain and a light shower?

You need a 'tipping bucket' type sensor to give you an estimate of how much rain there has been, but even then you need to do some work with experimentation to get reasonable accuracy.