Looking for cheap knx switch-interface

Hardware Home Automation
1

Hi,
is there a way to get a cheap knx switch interface?

I know, i can connect ordinary wall switches with knx binary inputs and so i can switch lights or do something like this.

But binary inputs are expensive. KNX-Sensors are much more expensive.

So if there is a cheap way to get a small knx interface behind a wall switch, this would be great? Something small like tpuart-interface maybe?

2

The cheapest way is the hardest way (yes, german native :wink: ) http://selfbus.myxwiki.org/xwiki/bin/view/Geräte/Taster/TasterBJ about 8EUR per wall switch, plus hours of happy soldering…

3

That´s it! But sad, that you can´t buy it completely soldered…

Is there anyone whon sells ready-to-use selfbus items?

4

Since several months have passed, I was curious about what you (or others here) ultimately chose? I too am looking for something to interface “traditional” switches and buttons.

My priorities include:

  • Reliable
  • Low latency
  • Ease of long-term maintenance
  • Some short of shielding/isolation between said I/O and Ethernet (or other interface)
  • OH2 integration
  • Costs

To achieve this, I am willing to pull wires wherever this helps. My ducts don’t have room to pull all the existing light switch wires to a single central location. However, as thinner cabling is used for the signal-only wires, I should be able to have all wires converge to only two locations. These already have DIN rails, a separate low-voltage area and Ethernet.

I too did consider a set of small distributed KNX or (Z-Wave or ZigBee) I/O boxes, but that is ending up to be quite expensive, and I am not sure about the maintenance in all those different places, one or more decades from now.

So right now I am increasingly looking at something like the Moxa ioLogik E1210 (description, PDF), which has 16 inputs for $185 (price from industrialnetworking.com).