Post by thread:PIC based frequency measurement for musical tunes

Is there any PIC based project on the net to measure (main) frequency of a musical instrument's sound to determine which note it play? Any suggestion how to do a fast-responce musical tuner ? spam_OUTalbertgoodwillTakeThisOuTgeocities.com __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com

probably the best way is to excite the strings, using the strings as part of the feedback loop so they are determining the frequency. Then use some form of frequency counter, probably by measuring the period of oscillation. There was an item on a science program in the UK recently where someone is developing a box to do this, but it went the whole hog and had motors to drive the tuning pegs on a guitar so it would auto tune it for you.

Albert Goodwill wrote: > Is there any PIC based project on the net to measure (main) frequency of > a musical instrument's sound to determine which note it play? > > Any suggestion how to do a fast-responce musical tuner ? Strobe wheel tuners are 'fast' (instantaneous). Basically a 6" disk spinning at a fixed rate (synchronous motor) and a neon bulb driven by the audio. They worked well because the harmonics of a tone didn't need to be filtered out. You can still find them in some music store's junk rooms. If you really want to do it electronically I would suggest using a zero crossing approach and 'pic' the longest period you find as your fundamental. A voltage controlled bandpass filter might be a nice addition to get you higher accuracy. If you want overkill, how about a FFT with adjustable sample rate so you can optimize the resolution?

Did you call it the tune-o-matic? Phil. On Monday, June 12, 2000 10:17 AM, Alan B. Pearce [SMTP:.....A.B.PearceKILLspam@spam@RL.AC.UK] wrote: > probably the best way is to excite the strings, using the strings as part of the feedback > loop so they are determining the frequency. Then use some form of frequency counter, > probably by measuring the period of oscillation. > > There was an item on a science program in the UK recently where someone is developing a > box to do this, but it went the whole hog and had motors to drive the tuning pegs on a > guitar so it would auto tune it for you.

Albert.... Your approach could depend upon the duration of each note you seek to tone measure. Do you wish to give a steady tone for 40 to 100 ms for example? A DPLL, digital phase lock loop, with a narrow feedback filter would give you accuracy if you wish to make the measurement with some noise present. Measuring/counting clocks between edges on a ZCD is subject to jittle, but averaging there too might help. Phil Anderson. Sounds like a fun project. On Monday, June 12, 2000 12:34 PM, Robert Rolf [SMTP:Robert.RolfKILLspamUALBERTA.CA] wrote: > Albert Goodwill wrote: > > Is there any PIC based project on the net to measure (main) frequency of {Quote hidden}> > a musical instrument's sound to determine which note it play? > > > > Any suggestion how to do a fast-responce musical tuner ? > > Strobe wheel tuners are 'fast' (instantaneous). > Basically a 6" disk spinning at a fixed rate (synchronous motor) and a > neon bulb driven by the audio. > They worked well because the harmonics of a tone didn't need to be > filtered out. You can still find them in some music store's junk rooms. > > If you really want to do it electronically I would suggest using > a zero crossing approach and 'pic' the longest period you find > as your fundamental. A voltage controlled bandpass filter might > be a nice addition to get you higher accuracy. If you want overkill, > how about a FFT with adjustable sample rate so you can optimize the > resolution?

> >Did you call it the tune-o-matic? > > I did not call it anything, it was just an item I observed on the show. I cannot > recall what name it had. I just know I've got an item about this tucked away on a video tape somewhere. "Things I'd like to have a go at" (ha !!). Which I can't find right now. However, the guitar in question was an item on Australian science program "Beyond 2000". So, a quick trip to http://www.beyond2000.com then a search for "guitar" brought up the item I remembered. The company is Transperformance, their web site site is (surprise surpise) http://www.transperformance.com I didn't linger long so don't know if they have pics of the beastie. If they don't I can tell you that the cavity behind the pickups is one mess of PCBs and screw motors. Very effective it was too. And quick