There is no evidence that negative reinforcement with ultrasonic audio works to train an animal. Just because you can't hear it doesn't mean it annoys them. Even if it does annoy them, (like a choke collar or yelling at the dog), it doesn't mean it trains them. My neighbor yells at his dog every day and it does the same thing. There is strong evidence that negative reinforcement only makes dogs aggressive instead of obedient.
You can train a dog with positive reinforcement and link that with a clicker so the dog eventually feels rewarded with a click - a random honk (even a honk in the ultrasonic) is not going to get a dog to stop barking.... but who am I to be untrusting of an expert on YouTube?
Now, continue with your project.