Here a tuner and frequency logger project I just completed.
The tuner uses yin algorithm from the teensy audio library, fft frequency estimation from here (had to edit cpu defines for T4), a bubble-display library from here, serial command library from here and my own led and button libraries. Also I put together some code for reading a wacky mechanical rotary encoder, similar to this code, with polling, so no interrupts (see attached files), it debounces fine.
The tuner can act as a device for musicians (it also has a metronome) and measures battery voltage: as soon as voltage drops it writes it's settings to eeprom. Various settings can be tuned via the serial interface and saved into eeprom. See screen shots for details and serial output of yin and fft.
left: first version with T3.6, middle T3.6 without display (will be used as a frequency logger for a project musicians and physicians are working on), right T4 with speaker, rotary encoder and lipo-charger.
voltage = 4.1V
T4 with transparent plastic cover
PCB designed in kicad
serial output of yin and fft
tuning the settings via serial
code files: View attachment tuner.zip
The tuner uses yin algorithm from the teensy audio library, fft frequency estimation from here (had to edit cpu defines for T4), a bubble-display library from here, serial command library from here and my own led and button libraries. Also I put together some code for reading a wacky mechanical rotary encoder, similar to this code, with polling, so no interrupts (see attached files), it debounces fine.
The tuner can act as a device for musicians (it also has a metronome) and measures battery voltage: as soon as voltage drops it writes it's settings to eeprom. Various settings can be tuned via the serial interface and saved into eeprom. See screen shots for details and serial output of yin and fft.
left: first version with T3.6, middle T3.6 without display (will be used as a frequency logger for a project musicians and physicians are working on), right T4 with speaker, rotary encoder and lipo-charger.
voltage = 4.1V
T4 with transparent plastic cover
PCB designed in kicad
serial output of yin and fft
tuning the settings via serial
code files: View attachment tuner.zip
Last edited:
reading the guitar tuner in counts of Hz, not notes and off-cents? Super cool project, thanks for sharing.