Velux Component - KLF 200 - Rain Sensor

Would be great to add the feature of getting the state of the “rain sensor” to the Velux integration (KFL 200). I would like to use the state of the rain sensor to prevent some automations from being triggered.

+1 for me on this

Also +1 from me.
Today I noticed a possible workaround: When the windows are closed because of the rain sensor, the position shows 10%. Therefore it does not show the state “closed”, this is only shown at position 0%.
Is it possible to add an additional status: “Closed (rain)” at 10%? That would be enough for me…

For now I just configured my Lovelace dashboard, that it shows the 10% position (Closed rain) in blue, so that I can at least see if the Windows are really open or actually closed die to rain.

For automations it is not enough, e.g. I would love to open the Windows again once the rain Sensor cleared. So big support for this feature request.

this I don’t think it can work in a consistent way: windows goes in 10% position if they are open and close themselves due to rain.

if they are at 0% and start to rain they keep 0% as value.

Said this having a rain sensor as output would be great: not sure if this is published through api though


the easy way is to put an Fibaro FGBS-222 Smart Implant cheap zwave device with open/close sensor channel ( there is 2 channel , named I5 and I6) . You plug 2 wire on negative an positive wire of KLF200 input (there is a relay into with box with rain detector) , you should link negative implant to negative supply

You just have to get state of channel with an automation and use it for anything
I done it , it fully fonctionnal


would you mind to post detailed instructions how you configured that in the KLF 200? I would like to try an analogous setup with the Homematic IP HMIP-SCI (which literally has batteries included, so no need for a power supply).

Thank you!

I just solved this problem for myself with a Fibaro Smart Implant (FGBS-222) – thanks to @manuroup for the inspiration – but directly on the sensor; so this solution circumvents the KLF 200 gateway altogether.

My rain sensor is a Velux 3LA A02 WW on a CVP skylight (of the series which was shut down in 2021, there is a new CVP series now). The sensor cable enters into a plastic distribution box with two levels “upstairs” …

… and “downstairs” which are connected with a pair of 3-pole Molex connectors (MOLEX 39014030/39014036):

The wires are grey, purple and black and described here in German. I found a constant 19V DC voltage (power supply for the heating of the sensor) between grey (+) and purple (–), and the sensor toggles a switch with between purple and black (open=“sensor dry”, closed=“sensor wet”).

[There is also an independent 19V DC power supply brown (+) / white (–) which I didn’t use.]

I connected the sensor wires with T-taps as follows (Velux rain sensor on the left, Fibaro Smart Implant on the right):

  grey --- P
purple --- GND
 black --- IN1

This is the 3-wire analog sensor connection scheme in the Smart Implant manual

The cleanest solution for the three T-taps probably would be an intermediate extension cable with the Molex connectors where you crimp each tap wire together with the tapped wire, and stow the extension cable in the “downstairs” compartment of the distribution box (there is very little space “upstairs”).

But I don’t have experience how to crimp these (and no special tools either), so I opted for heat-shrinking soldering connectors (AWG 26-24 “white”):

  • Cut each of the three wires of the rain sensor s.t. you have enough free space to maneuver.
  • Drill one end of each tapped sensor wire with a thin tap cable leading to the Smart Implant. Insert this into one side of the connector.
  • Insert the other end of the tapped sensor wire into the other side of the connector.
  • Take care that all wire ends end up together under the soldering ring.
  • Heat-shrink (beware not to deform the plastic of the distributor box!).
  • Stow the distributor box.
  • Test the rain sensor (drip some water onto it).

I cut the sensor cable on the “sensor side” (in the “upstairs” compartment) because I didn’t want to mess with the “house side” of the cable. If anything went wrong, I could just buy a new sensor and plug it in via the Molex connector again. The Smart Implant resides “downstairs”, it fits very nicely in my distribution box.

The tap wires must be thin enough to fit through the hole where the Molex connector resides. The Smart Implant wires are thin enough. I did not connect them directly because I didn’t want to run the risk to have to touch the soldering connectors again for rewiring. Instead, I used unneeded wires which I just cut off; no worries, this is a standard JST 8-pin 1.0 mm connector which you can get off eBay or AliExpress for pennies), and used 2-pole Wago 221 clamps (you need to crimp the wires white wire terminals) to connect the tap wires to the Smart Implant wires. The Wago clamps just fit right in, too.

The Smart Implant parameter 20 “Input 1 – Operating mode” must be set to “4 – Analog input without internal pull-up (Sensor Multilevel)”.

With the Z-Wave JS integration, you end up with a numeric sensor “Voltage (3)” which is around 1V or below when the sensor is wet and around 4V when it is dry. The following template sensor does the job to transform the analog signal to a binary sensor:

  - binary_sensor:
      - name: regensensor_lichtkuppel_flur_is_wet
        state: >
          {{ 0 < states("sensor.regensensor_lichtkuppel_flur_voltage_3") | float(0) < 2 }}
        availability: >
          {{ not is_state('sensor.regensensor_lichtkuppel_flur_voltage_3', 'unavailable') }}
        icon: >
          {{ is_state("regensensor_lichtkuppel_flur_is_wet", "on") | iif("mdi:weather-pouring", "mdi:circle-outline") }}
        unique_id: fbe43771ee234abbedd9bbc35ebc33bcbb8faca0

Is there more info on the rain sensor ?