Having designed the mechanical prototype using FreeCad, I finished building and assembling the hardware during the last two days. I have milled the fan's casing, servo parts and the lamellae from birch plywood using my CNC router. The bearings for holding the lamellae in place were milled from POM (Acetal). All parts are available via my GitHub account. Although my first intention was to build the whole device from acrylic glass I found it much cheaper and more convenient to build the first prototype from wood. After cutting the glass fiber rods I assembled everything using (a lot of) superglue:

As can be seen from the image above and the screenshot below, the mechanical setup is really simple. The horizontal and vertical lamellae are connected to the corresponding servo motors. Hence, the servos linearily control either the horizontal or vertical direction of air flow.

In order to test the mechanics, I hooked up the servos to a spare RC receiver controlling the servos via an RC remote. The mechanics seem to work really well. I will upload a video soon.

Next step will be to hook up the servos to the Raspberry Pi and start coding...