in general, you need a tank to hold the smoke oil, a pump of some sort to pump it, either electrical or powered by the engine, and then in most cases a valve controlled by a servo that will let you start/stop and hopefully also meter the flow.

that said, there is a thread over in the gas forum IIRC where a guy constructed one powered by pressurized air in a air horn cylinder. no remotely adjustable valves, just a needle valve that is started before flight.