Move to HomeMatic

After a while I was a bit unhappy with the reliability of the FS20 <-> io-homecontrol® system I had created. I was looking for alternatives and found it in the HM-LC-SW4-PCB, which is a HomeMatic 4 channel switch. If you buy it as a kit it is available for 29,95 € per unit. The soldering was no problem at all with the included instructions. The principle is quite the same as with the F20 switches, I always connected two Velux remotes to one HomeMatic switch.


As HomeMatic is using a bi-directional protocol the reliability of the whole system increased significantly.

Now the shutters are being closed automatically at sun-set and are opened up at sun-rise. If the sun rises before 07:00 CE(S)T the shutters will stay closed until 07:00, this helps getting enough sleep during the summer period.

IMPORTANT NOTE: do not open the shutters in the bedroom on weekends automatically, trust me!

Control Velux io-homecontrol® products via FS20

I always wanted to connect my Velux electrical shutters with my HomeAutomation system. The solution Velux proposes is as follows; buy a KLF 100 (250 €) per electrical shutter (in fact you could also build some groups, but who wants to limit the flexibility) and don’t forget you also need an actuator from your HomeAutomation system to steer the KLF interface.

7 * KLF 100  (250 € each) = 1750,00 €                                                                                    4 * FS20 EM4 (18,95 € each) = 75,80 €

Obviously this is a bit expensive, there must be a different way. For every electrical shutter I already have a Velux KUX 100 (the basis electric control unit) in place, which comes with a small remote control. So I decided to use those remotes together with the above mentioned FS20 EM4 as the basis for my tinkering.


The whole installation has found its place in an ikea plastic box.

I stripped the remotes from their casings, modded them to run with an external power source and connected both pins from the up / down butt contacts with cables which will be used to solder it to the FS20 module.

FS20 EM4 connected to Velux remote control

Each FS20 EM4 module is capable to control 2 Velux remote controls if you only want to control the up and down button. Why this is sufficient will be explained in a second.

The remote knows two operational modi:

  1. short press on the button, the shutter moves into the desired direction until it reaches the final position
  2. constant press on the button, the shutter moves into the desired direction until it reaches the final position or until the button is released

The emulation of the 1st modus has turned out not to be sufficiently reliable, therefore I decided to switch the buttons on for 50 seconds (the shutter will need between 45 and 48 seconds from final position open to final position closed and vice versa). To stop in between the final positions I simply switch off the button and the shutter stops. One of the further advantages of this approach is that the use of the remote controls stop button is not required.

Supply lines on the back side

On the back side of the box I placed the supply lines:

  • 5 Volt for the FS20 Modules
  • 3 Volt for the Velux remote controls

In a next step I also want to connect to Somfy remote controls following the same principle.