Re: [sdiy] Tuning indicator

Fri Nov 15 17:59:22 CET 2002

Hah... I remember that better than you....

we had a different version in the states... but it uses
an up/down counter... the guitar gets squared up and causes the
counter to go up, the reference makes the counter count down...

when the frequencies are close the LED steps at the beat frequency
rate.

There was another flop-flop at the overflow... that latches the direction of the count... so if you are way off it indicates 
'too high' or 'too low'....

An alternate design from EDN or Electronic Design (late 70's maybe
early 80's) used four LEDs to achieve the same effect.

I too... lost it all except the TOG chip ;^P

You might use a bicolor LED driven between two op-amps ... one
for reference and one for unknown frequency... and watch the
color change. In beat, they should change very slowly...

H^) harry

>
>>Here's how I would do it...  (and most of you know that I almost never
>>do things the normal way).
>>[...]
>>I'm surprised nobody makes tuners like this.  It would be so much
>>better than those cheezy digital tuners.  Sure it'd be expensive,
>>you'd need one of these displays for each of the 12 chromatic notes,
>>but it would be so nice to use.
>>
>>  -- Don
>Hi Don,
>I have seen (and built from a kit) something very similar.
>I don't remember all the details, but it worked with a counter
>(4017 ?) instead of a bargraph, and the LEDs were arranged
>in a circle. So when the the guitar tone was too high, the LED
>light would circle in clockwise direction, and when it was too
>low, in ccw direction. This was very nice too look at, and
>if also was very intuitive because you had to turn the screw
>on your guitar head in opposite direction of the LED point.
>I have thrown this box away when I had given up to learn
>the guitar, and after I canibalized it for theTOS chip.
>The kit was presented in a German electronics magazine,
>I guess Elrad or maybe Elektor.
>JH.