Freetronics temperature and humidity sensor mount

When building a heat extraction system I needed to measure the temperature and humidity of the air being extracted from a room. The air vents I was using had a neat little hole in the middle, covered by a plastic plug that just popped out. I designed this to fit in the hole at the back of the vent and hold the Freetronics sensor board. The board mounts with the sensor facing towards the air hole.

The small squarish plug beside the holder mounts on the outside of the vent to neaten up the appearance of the hole once the original cover was removed (it had rather rough edges)