The spotlight has a self learning receiver which can be programmed to a number of transmitters, the supplied remote control or the NetHomeServer for example. It is this receiver we are after.
Ok, time to take it apart. Below the surface is a nice little circuit board. You can see the antenna to the right and the LED:s in the middle. When I flip the circuit board it becomes more interesting.
To the right are the HF receiver parts. I guess the lower right and the far left circuits are some kind of power drivers for the LED:s and the top right is probably the receiver signal decoder. There is one connection that looks like a good candidate for being the decoded on/off-signal.
I have scraped off the coating on it to be able to solder a connector there (at the blue arrow). Measuring the voltage there shows that the level is close to 0 when the light is off and about 90% of full voltage when the lights are on. Ok – we have a receiver! Now all that is left is to remove the LED:s and remove the board from the housing.