Hey guys.
I've been working on a Guitar Tuner. I'm using a PIC 16F684.
The analog part of the circuit was lifted from this site:
http://www.schickt.de/index.php?entry=entry080606-004307 which in turn was lifted from another site...
Thing is, i don't have an oscilloscope, so i don't know exactly how the waveform looks like when it reaches the PIC. There are some note stability issues that i think are related to harmonics being generated mostly on the thicker strings.
Does anyone have any experience with anything like this?
This is what i've got so far:
http://www.youtube.com/watch?v=keURkUKPppUThe note recognition is lightning fast, i'm measuring the period and calculating the frequency from that. I'm thinking about doing some simple analysis of the data prior to using it for the calculations but still, i don't really know if the most frequent period is the correct one.
Lets say that i have an analysis phase where from a sample of 20 periods. Just keep the most significant byte, for memory saving purposes and because the slack it gives me will compensate for slight variations that are perfectly acceptable. See what is the most common value and for the data collection phase, basically an average of the values, i would only consider the values that have the most significant byte equal to the most frequent one.
Does this make any sense? Any other suggestions i should consider?
The tuner is usable as is, but because it's for me. Anyone else would be very annoyed that they have to pluck the E string very gently to get a good reading.

I would already have tried this idea if i wasn't so tired, so instead of messing up my code, today i'm just going to ask for fresh ideas.
