- appropriate stick (I used a wooden spade handle 4 centimetres in diameter — enough for me),
- strong enough rope,
- thinner cord to attach...
- ...a piece of rubber ribbon,
- fix bolt (2 PCS).
The bar is hanged on the two pieces of rope. On each side the constrictor knot is used to attach the middle of the rope to the end of the bar. Then the bowline knot loop is made with the two ends of the rope together. Lengths should be adjusted so that freely hanging bar is on its place.
Then the lifting mechanism. A piece of rubber ribbon (anything that stretches may be used) is attached to the middles of vertical ropes so that when there is no load, the construction lifts up. In this position the ropes and rubber ribbon form a '>---<' figure. When you pull the bar down, the rubber stretches and lets all go down to '|---|'.
I have concrete walls, so I used fix-bolts like this. You may see that there is also kind of a ledge under the ceiling so the bar is almost hidden in the upper position.
There is a sketch of another variant of lifting mechanism. It is a bit more complicated, but the space above the bar becomes free (e.g. for making turns). You'll need more cord and a place where to attach the stretching part. Note that the bar will stay horizontal while going down and up even if pulled at the side.