A Carpenter Bee trap is easy to make. Use any wood you have laying around. I used a 2x4 rough cut Cedar, and cut off pieces 4 1/2" long. Drill a 1" dia hole (which will be the bottom) about 3" deep in the center of one side. Then use a 1/2" drill to go at a 45 deg angle to come out in the one inch hole. Put some kind of clear container on the one inch hole to catch the bees. You can drill as many 1/2" holes as you have room to depending on the size of wood you use. More holes give more opportunities for bees to enter the trap.
They fly around looking for a dark spot on wood, which is the hole from their previous presence. They see the small hole in the trap and enter. They go up in the 45 deg angle, get into the 1" hole and go down. Now they are in the clear container, and caught.