I recently hooked up my large dust collector to a central pipe system that can be hooked up permanently to the table saw and miter saw. This is great for convenience since the tools will be always hooked up. Each tool needs it's own blast gate so that the suction can be focused on the tool in use. However, there wasn't a great location for the blast gates to be mounted since the pipes ran along the wall and were out of reach.
So I made these - cable driven blast gates. They allowed me to mount the blast gate high on the ceiling and out of the way, yet still open and close them from a convenient spot with the handle. Check out the video below to see more detail on how I built them.
I designed both a 4" version (for use on 4" PVC sewer drain pipe) and a 2" version (for use on 2" ABS drain pipe).
If you are interested in building one yourself, you can download the model on my Downloads page.
Main video on 4" blast gate & details on design:
Second video on 2" version of the design: