When I was still at school, I made one almost like this, but it was motorized:
The motor was attached to the board and had some kind of hub fitted to its shaft. It was positioned near one of the wheels so that the hub exerted just enough pressure on the wheel to make it spin - you'll have to carefully adjust it to get just the right pressure. You may find that the drum tends to move to one side and even hop off. If that happens, you can attach a bracket or something at one end of the board to stop the drum moving too far. Mine rotated in only one direction, but that was no problem with either Ciba or color prints from negatives. If you prefer, you can set it up with an electronic timer that periodically changes the direction - there are many instructions on the web for that.
