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Autocorrelation rocks for Engine RPM

Started by Robert Scott June 10, 2013
Den tirsdag den 11. juni 2013 00.12.29 UTC+2 skrev Robert Scott:
> A while ago I posted a question about how to extract pitch information > > from the messy sound of an engine. It was for an iPhone app I have > > developed which displays the RPM of an engine based on the sound it > > makes. Vladimir and other suggested autocorrelation as used in pitch > > detection in speech. Thanks, guys! After a long time struggling with > > various ad hoc ways to qualify peaks in the FFT and match them up with > > harmonics of the fundamental pitch of the engine, the autocorrelation > > method beats them all by a long shot. I finally got it all > > implemented into my app, which also displays a real-time graph of the > > autocorrelation function. I have tested it on lawnmowers, string > > trimmers, generators, motorcycles, industrial earthmoving equipment, > > and single-engine airplanes. In almost every case the graph was clear > > and the RPM calculation was solid. I wish I had known about this > > three years ago when I first released my app. I could have avoided a > > lot a bad reviews. Thanks again. This is a new tool in my toolbox. > > > > Robert Scott > > Hopkins, MN
kinda related or at least interesting :) http://www.youtube.com/watch?feature=player_embedded&v=MtrSNFjkGdU#at=97 -Lasse
On Thu, 27 Jun 2013 13:59:13 -0700 (PDT), langwadt@fonz.dk wrote:

>Den tirsdag den 11. juni 2013 00.12.29 UTC+2 skrev Robert Scott: >> A while ago I posted a question about how to extract pitch information >> >> from the messy sound of an engine. It was for an iPhone app I have >> >> developed which displays the RPM of an engine based on the sound it >> >> makes. Vladimir and other suggested autocorrelation as used in pitch >> >> detection in speech. Thanks, guys! After a long time struggling with >> >> various ad hoc ways to qualify peaks in the FFT and match them up with >> >> harmonics of the fundamental pitch of the engine, the autocorrelation >> >> method beats them all by a long shot. I finally got it all >> >> implemented into my app, which also displays a real-time graph of the >> >> autocorrelation function. I have tested it on lawnmowers, string >> >> trimmers, generators, motorcycles, industrial earthmoving equipment, >> >> and single-engine airplanes. In almost every case the graph was clear >> >> and the RPM calculation was solid. I wish I had known about this >> >> three years ago when I first released my app. I could have avoided a >> >> lot a bad reviews. Thanks again. This is a new tool in my toolbox. >> >> >> >> Robert Scott >> >> Hopkins, MN > >kinda related or at least interesting :) > >http://www.youtube.com/watch?feature=player_embedded&v=MtrSNFjkGdU#at=97 > > >-Lasse
Nice example. ;) I've seen that guy's vids before and he's really good at mimicing the sounds. Also, looking forward to the new engines next year! Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com
Den fredag den 28. juni 2013 00.10.31 UTC+2 skrev Eric Jacobsen:
> On Thu, 27 Jun 2013 13:59:13 -0700 (PDT), langwadt@fonz.dk wrote: > > > > >Den tirsdag den 11. juni 2013 00.12.29 UTC+2 skrev Robert Scott: > > >> A while ago I posted a question about how to extract pitch information > > >> > > >> from the messy sound of an engine. It was for an iPhone app I have > > >> > > >> developed which displays the RPM of an engine based on the sound it > > >> > > >> makes. Vladimir and other suggested autocorrelation as used in pitch > > >> > > >> detection in speech. Thanks, guys! After a long time struggling with > > >> > > >> various ad hoc ways to qualify peaks in the FFT and match them up with > > >> > > >> harmonics of the fundamental pitch of the engine, the autocorrelation > > >> > > >> method beats them all by a long shot. I finally got it all > > >> > > >> implemented into my app, which also displays a real-time graph of the > > >> > > >> autocorrelation function. I have tested it on lawnmowers, string > > >> > > >> trimmers, generators, motorcycles, industrial earthmoving equipment, > > >> > > >> and single-engine airplanes. In almost every case the graph was clear > > >> > > >> and the RPM calculation was solid. I wish I had known about this > > >> > > >> three years ago when I first released my app. I could have avoided a > > >> > > >> lot a bad reviews. Thanks again. This is a new tool in my toolbox. > > >> > > >> > > >> > > >> Robert Scott > > >> > > >> Hopkins, MN > > > > > >kinda related or at least interesting :) > > > > > >http://www.youtube.com/watch?feature=player_embedded&v=MtrSNFjkGdU#at=97 > > > > > > > > >-Lasse > > > > Nice example. ;) > > > > I've seen that guy's vids before and he's really good at mimicing the > > sounds. > > > > Also, looking forward to the new engines next year! >
yes it will be really interesting, getting the KERS, TERS and engine to work together and not least provide power and braking in a way that the drivers can control will be incredibly complex The 2014 Le Mans LMP1 has the potential to be even more technically interesting, They will have a fuel flow limit plus a fuel allocation per lap, but the rest is much more free, no limits on cubic capacity, number of cylinders, variable geometry turbos etc. and up to 8MJ ERS per lap -Lasse