guitar tuners?

[Branimir]

hello!

i was google-ing lately, actually i was interested in building a guitar tuner...

why?
dunno, sounds like an exciting and more complex task than distortion boxes and similiar devices, and actually i'm kind low on money right now, but high on components in my basement, so givin 100$ for a pedal or a rack tuner, doesn't sound quite pleasing...

any links, recomendations?
perhaps a TU-2 schematic

cheers!

[Transmogrifox]

Hmmm--I can't think of where I've seen any tuner schematics.  I have taken a couple tuners apart and found pic chips and microprocessors in them.  

The theory is generally based on a multiplication scheme.  If you multiply a signal with one of its own frequency components, you'll get a DC term, so you can use this relationship to identify which frequency components are in a signal.  

Anyway, I thought I'd bump this thread because I'm also curious if anyone has any tuner schematics.  It would be interesting to see the different approaches used to do this.

[Branimir]

yeah, i tried searching these forum regrading tuners and i did stumble upon some PIC related projects.

but none of these seemed mature (project-wise) to try to build them...

guess buying a boutique tuner is still a way to go, huh...

[ethrbunny]

There is a thread (somewhere.. at least once) talking about this (except that I can't find it.. d'oh). Its a PIC project with C code. Once you've bought the PIC programmer and all the bits you'd have spent way more than a stomp tuner ('cept maybe one of the fancy strobe types).

Other than the PIC aspect it wasnt a v difficult project. There were some easy ways to improve it.

[ethrbunny]

Here's one:

http://www.circuitcellar.com/library/designforum/pic/porzio/index.asp

[ethrbunny]

... this is the original one (with source code.. instead of vague references to it)

http://www.myplace.nu/avr/gtuner/index.htm

[nelson]

My idea for building a stompbox tuner was just taking a cheap non stomp box tuner and making it footswitchable in its own enclosure. you would just need to find a suitably sized and suitably well lit tuner. a single DPDT could do the switching, it would act as a mute switch too. would be cheaper than buying a pedal tuner. Its the only "viable" half DIY way I could think of doing it, without delving into PIC.

[MetalGuy]

Couple of monts ago I was asking for guitar tuner schematics because I wanted to build one into my amp. Snce then I tried 2 of them /PIC based/ including the first one from the previous posts but unfortunately none of them worked. The reason was the source code. I gave up. I'm not into the programming at all.
If you have more luck let us know!

Good luck!

[col]

There are a few tuner schematics in the Babani books available in the UK (and elsewhere?) by R A Penfold (I think, I'll check this). I think that they are just tone generators though to give you a note to tune to. I'll check properly tonight.

[James P]

I've always wondered how the old Conn Strobe tuners worked. I think it was a tube based circuit, though i'm not too sure. Try and find one now, they're rare as hens teeth!!

James P

[petemoore]

Strobe Tuner is extremely accurate, as accurate as the 60 cycles per second coming from the wall outlet.
 The string makes the strobe light flash at 'x' frequency, behind the spinning wheel with 'the lines', the wheel speed is exactly determined by the 60 cps. of the AC supply voltage. When the lines' frequency [how many lines pass the center marker per second...] matches the string frequency, the optical illusion makes it look like the lines 'hold still'.
 According to Gibson, guitars cannot be made to play in absolute perfect tune, high strings to low strings, up and down the neck....pretty close is as good as it gets, compromise must be made...if I want a 'perfect' open G chord, the tuning will need to change compared to perfect E tuning...tuners don't 'think' about that.
 IF the guitar is 'perfectly' set up, a strobe tuner will get nearly as good a tuning as a 'perfect pitch ear' tuning...if there are 16 strings/3 different instruments [like two guitars and bass], I recommend checking the tuning by ear after using a tuner on them, at least once...chances are you'll find an 'imperfect' tune on one of the open strings, or a fretted one.
 An Out of tune guitar can sound cool...depending.

[scratch]

I've got a schematic from a Canadian magazine (1980's) article for a guitar tuner based on a TOS chip. Now TOS chips are hard to find, and equivalent replacents can be had, but generally cost in the $30-40 range. I've been trying to replace the TOS chip with a divider made up of regular CMOS digital chips, but haven't finished debugging it ... should only require a couple of programmable decade counters and a gate chip and a pile of diodes. If got some clock bleedthrough in the the tone output so i'm going to re-breadboard the whole thing and cleanup my analog and digital grounds and see if that fixes it ... I've been working on this for months, and my wife has other 'projects' for me ...

[MetalGuy]

This one was looking promising but unfortunately I couldn't to work:
http://mattzz.dyndns.org/twiki/bin/view/Projects/GuitarTuner
I wrote to the guy, he answered that this was an old unmaintained project and finally he said he couldn't help.
It looks like the source code needs some minor tweaking but that's far beyond  my PIC knowledge.

[Samuel]

 According to Gibson, guitars cannot be made to play in absolute perfect tune, high strings to low strings, up and down the neck....pretty close is as good as it gets, compromise must be made...

Anybody interested in this property (of all musical instruments) should go read Temperament by Stuart Isacof (http://www.amazon.com/exec/obidos/tg/detail/-/0375703306/qid=1118788098/sr=8-1/ref=pd_csp_1/002-5103198-4244041?v=glance&s=books&n=507846)  for a good layman's read of how our twelve-tone tuning was arrived upon after decades of input from some of the greatest minds in history...Interesting stuff. In short, our entire tuning system (leaving aside the particular foibles of guitars) is a big compromise...

[tadas]

It's a bit offtopic, but...

My colleague told me about his guitar tuner based on cellphone idea. Almost every modern cellphone has a java virtual machine (java 2 mico edition), sooo that means we can write a software guitar tuner for it and use mobile phone mic for input (but i'm not sure if j2me gives access to microphone).

Could be usefull for acoustic guitar owners  

[col]

One of the Babani books (see FS forum under my name) has a tuner in it based on flashing LEDs that says you can tune to within 0.25Hz. The other book I have with one in is simply a tone generator.