I use an injector that I bought at Academy sports, its designed to inject stuff into meat.
That trash can setup looks like it would work fine. The only thing its missing is water, its best to have a bowl of water on top of the wood ships... it boils and evaporates as the meat cooks, and does two things, one is to keep the meat moist, and the second is to flavor the meet... you add a fair amount of what you otherwise would have used to marinate the meat to the water, as it evaporates it imparts this flavor to your meat.
also, there is no need to change the wood chips. I used to do this, but ran out one day, and found that it made virtually no difference. The first batch of wood chips, if soaked in water, smoke for about an hour or so before they are ashes... and it seems that this is plenty to give the meat all the flavor you want.
And the water really is important, ive tried it with and without. With water mades the meat much, much moister.