Comment by pedalpete | Hacker News Reader

Comment by pedalpete | Hacker News Reader

Parent Full thread

About 7 years ago I was toying with making an open-source raspberry pi with a decibel meter you could stick to your window and it would listen for loud noises and tweet the police department to say that a loud noise (likely motorcycle groups that ride up and down my street) had been located at X location.

I had a few friends who said they would also put them in their windows, so we could have a few devices coordinate to confirm it wasn't just a loud neighbour or something.

I built a prototype, but when I started measuring how loud the motorcycles were, it was often within the legal limits (I think 80db or something).

Partly, this is because it was inside my apartment, but they sure sounded loud.

I spoke to a police officer friend about what to do, and he said the police just didn't care. I pointed out how easily they could use a decibel meter on their phone to measure how loud, but it was a complete non-interest for them.

Good to see NYC taking action on this. Hopefully more cities follow suit.

>use a decibel meter on their phone to measure how loud

Phone microphones are not calibrated for this and the apps just spit out completely wrong numbers. They show relative noise changes fine but one phone could show the same sound at a higher or lower db rating just because the mic is a little more amplified or something.

The Apple Watch actually is calibrated for this and has a built in app which shows noise levels quite accurately.

> I spoke to a police officer friend about what to do, and he said the police just didn't care. I pointed out how easily they could use a decibel meter on their phone to measure how loud, but it was a complete non-interest for them.

Ostensibly this is because the incentives aren't aligned properly. The reason why many areas over-enforce traffic violations is because of quotas and incentive structures that encourage people to hand-out tickets. If you did the same thing with noise, you could actually encourage departments to try to enforce this.

I had a neighbor with a Dodge Charger with no muffler. I talked to a police officer about it. He basically told me that he himself drove a loud car, and his neighbors complained to him about it because he leaves for work at 5:00 AM, and that's the nature of sports cars and you just have to get used to it.

You could sue him in small claims court.

So much wrong with this...

80db is a measure of relative sound level, not the absolute level.

And vehicle noise levels must be measured at a specific distance to be useful.

Reply on news.ycombinator.com