Hi Pieter, Eric and others,
I've been trying the Lumotech mains dimmable LED driver (nowadays sold by Klemko) with a Marmitek plug in lamp module. It seems to be generally working ok (but see below); at least no difference with the Xanura DAIX module.
What I'm worried about seeing the diagram, is the type of LED lights you (Eric) would like to use. You are talking about 12V LED lights, but note that the Lumotech driver is only suitable for powerleds working at a constant current of 350 or 700 mA. Voltage is then a function of the dim level/led type, according to the P = V * I that we all knew in our younger years

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So please be careful with the type of LEDs you are going to use to make it all work. Make sure that these are powerleds (if the LED lights contain 6 to 12 or so individual leds in the fixture, you can be pretty sure these are not going to be powerleds).
Suitable LED lights might be Lumotech (or Klemko) Luxor fixtures, in combination with the IP67 outdoor in-ground housing. Nice feature is that the LED fixtures can be put at an angle in the housing to light certain objects in your garden.
See
http://www.klemko.nl/user_files/LED%20artikel01.pdf for more information on these fixtures/housing.
Also read this topic for more info on LED dimming:
http://www.domoticaforum.eu/topic.asp?TOPIC_ID=626
Another point of care: I've been using small power LED fixtures (Lumotech Luxi and Luzern) connected to Lumotech dimmable LED drivers at two more places in our house, and it seems that the flickering effect I descibed in
http://www.domoticaforum.eu/topic.asp?TOPIC_ID=182 is somewhat worse in these two installations; it occurs at different dim levels (but can always be fixed by increasing/decreasing the dim level a little bit). Using Marmitek or Xanura is not making any difference here, so it seems to be the LED drivers itself in combination with the load (certain loads are not stable?) Or both Xanura and Marmitek are not the ideal choice for dimming the Lumotech driver? Or maybe the 350 mA channel of the driver is more stable than the 700 mA channel?
I'll neeed to experiment some more (by varying the number of LEDs, connecting them to the 350 mA channel of the driver, etc.) and also need to check if certain dim levels are always non-flickering, so I can have Homeseer adjust the dim level to exactly these levels, given bright/dim commands.
Another option would be to switch to DMX for controlling these LED fixtures, using either a DMX -> 0-10 V signal -> 0-10 V dimmable LED driver or a directly DMX controlled powerled driver, both being offered by [url]
http://www.dmx4u.nl[/url[.
Sigh, so many things to find out and so little tim

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I hope this helps...
Lennart