Tuner 0.1

The Tuner is an old project, inspired by the tuner sub-circuit proposed by LMNC in his amazing Performance VCO.

This is an older version. Please, check the latest informations here.

The software I use is the one written by Jos Bouten and can be found at https://github.com/josbouten/Tune-O-Matic.
He also describes his own implementation of LMNC circuit at https://lookmumnocomputer.discourse.group/t/tune-o-matic-tuner/36.

MyModularJourney also made his own version and can be found at https://github.com/MyModularJourney/Tuna.

The circuit and the software are pretty basic and can struggle sometimes finding the actual note. But globally, it’s a very useful tool, which should be installed in any system.

In my version, I use an Arduino Nano. It is responsible for both calculating the tuning and displaying the result.
I chose to not use an opamp, in order to keep the component count low. The Arduino input is nevertheless protected by a Zener diode D5, behind an AC coupling capacitor C2 and a protection resistor R6.
The 7 segment display can be either Common Cathode (CC) or Common Anode (CA) and the jumper S1 selects which type of display is installed.
The 4 jack sockets are passively connected. This way, you can insert your signal on any connector, and get 3 (passive) outputs. So, even if you don’t use the tuner feature, the module can still be used as a simple 1 to 3 passive multiple.

3D view of the front of the PCB

3D view of the rear of the PCB


You can buy the partial kit, with the main PCB and the front panel on ko-fi.com.

2 thoughts on “Tuner 0.1

  1. Hello, im interested in the Tuner 0.1, I wonder if it can be set to tune to A=442 Hz (or other frequencya reference) since I play along acoustic Harmonica, which alays come in A 442 and cannot be changes.

    1. Hello Juan,
      You question brought my attention to a bunch of bugs in the original code. The frequency table states if a given frequency corresponds to a note, and how far from ideal it is. Well that table had a lot of incorrect values. This resulted in weird behavior.
      So I created a script that generates (I hope) correct values. And in the same time, to answer your request, I gave to the script the ability to select any frequency reference for A4.

      The code has been updated here: https://github.com/josbouten/Tune-O-Matic
      The script for updating the frequency table can be found here: https://github.com/josbouten/Tune-O-Matic/blob/master/freqs_ranges.rb
      Other bugs are investigated too, and there might be some improvements in a very near future.

      Also, I’ll redesign/upgrade soon the hardware of the Tuner and release a V1.0

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