Novelty! - Fart detector!

There really is everything, as long as there is demand, there will be a market, and someone will create it. Have you heard of a fart controller? Damn... In fact, it was created for the purpose of having clean air, and this kind of thing actually exists... Surprisingly, it does:

As soon as the detector senses methane gas in the air, it will emit an alarm sound. Hehe, using it to tease people would be quite amusing :)