Light cover for HM-Sec-Sco

thingiverse

If you're having trouble with a Homematic Window-/ Door-Contact "HM-Sec-Sco" that's not detecting opening and closing correctly, here's something that might help. First, check if the contact is properly working by ensuring there are no obstacles blocking its view of the window/door. If everything looks good from this end, then it's probably the issue with the light reflection inside the housing of the contact. This often happens when you put a white cover on the contact - using a brown one might solve the problem. Some people online suggest painting the inside of the cover black to fix the issue, but this didn't work for me. I found that a simple solution was to use a cover for the sending & receiving LED unit. This prevents light reflection and solves the problem. To install it, just open your contact, remove the transparent cover, and place the new cover over the send/receive unit (the little black spot with two LEDs). It's recommended to print this in black.