Four Spray Humidifier Module DIY Humidifier Control Board Atomizer Drive Board Four Way Ultrasonic Drive Board

I suspect this board and piezo emitters are designed for some existing commercial product, as they aren't really sized for DIY use, but it does work. Because the power is USB-C, the board isn't potted, and the buttons you need to control it are soldered to the board, though, it's a pain to really integrate into anything.

This is a neat kit of parts, but fragile. I damaged one unit during assembly. The rest work. Longer wires would help the hamfisted like myself do better. I like to think of the possibilities with these parts but have not committed to any yet. I'm thinking Halloween props.

The emitter works really well and I was impressed by how much most you can get out of it. Even just one running for a few seconds created a visible fog in the pot I had it in. I took off 1 star for two issues. First. The power board is not water proof, so you’ll need to find someway to keep it dry or this is going to be a short lived device. Second, the leads on the emitters are very short. You could extend them in various ways, but as shipped it is hard to work with. And with the board bot being waterproof, the board ends up very close to all the water you’re throwing in the air.