OP
I have two Carpenter Bee traps that I use, made of untreated pine wood, a rectangular shaped box with a 1/2" diameter hole drilled into each side, with a clear empty Gatorade bottle attached at the bottom. I hang the traps, one at each end of my house.The Carpenter bee finds the hole, crawls inside, sees daylight at the bottom and flies into bottle. Bottle fills up with dead carpenter bees, replace bottle with new one.
But I must say, papajohn's Bug-a-salt looks like more fun.
Built one like yours and hung it on my porch all summer.......Caught 1 bee....Apparently doesn't work everywhere. Glad it works for you.