Project Ideas

​​Tuning features of this device will interface with virtually any musical instrument in one of three ways: a MEMS microphone, a direct line input (1/4" mono input), or a piezoelectric transducer (both integrated and an external clip-on). Each signal will require pre-amplification, adaptive filtering, and analog-to-digital conversion before being passed to an MCU.[1] To address remaining noise components in the signal, additional filtering can be applied digitally through the MCU. The processed signals frequency will then be measured by comparing the waveform versus time. The result will be displayed on an OLED display, where the input signal can be compared to software defined values that reflect the pitch, i.e., the frequency of a specific note, that the input signal is closest to, represented in cents, i.e., a logarithmic measurement between two chromatic notes, known as semi-tones. [2][3] This feature allows users to correct the pitch of their instrument, whether it be stringed or otherwise, to be in tune with a musical standard. The standard can be adjusted in two ways, the first being temperament, the second being reference pitch calibration. Temperament is a standard that alters the intervals between notes in a variety of different ways, and is most useful in regard to historical music or Eastern tuning systems that differ from the 12-Tone Equal Temperament system most commonly used in music created after the 18th century. [4] Some examples of other temperaments include: Pythagorean Tuning, Just Intonation, and Meantone. Reference pitch calibration allows users to adjust the fundamental frequency of the reference pitch. In 12-Tone Equal Temperament, this is A4, which is 440 Hz. Calibration allows this frequency to be adjusted up or down, which in turn alters the fundamental frequencies of each semi-tone higher and lower than the reference, with respect to the mathematical standard of the selected temperament.

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Metronome and Tone Generator features of this device can use either the MCU or a 555 timer or VCO, integrator, and amplifier to produce signals at different frequencies and intervals.[5][6][7] The metronome will primarily use signals passed at specified intervals and output them as either sound using a speaker or a mechanical wave using a vibration motor. The tone generator will provide a number of features such as the option to select the frequency that is played, a tone that plays in response to an input signal and outputs the tone closest on the selected temperament/calibration parameters with respect to the input signal, and additional features for ear training, rhythm training, and theory training exercises. Training material will initially consist of simple exercises such as: chord and scale lessons and ear and rhythm training exercises.

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Recording features will allow users to record, store, playback, and download audio recorded at 44.1 kHz / 16-bit, all stored on an SD card integrated to the device using SPI.[8]

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User interfaces will include: an OLED display controlled with a rotary encoder for easy navigation of menus, item selection, and parameter adjustments; and a power and menu button.

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A buffered 1/4" output is provided to lower the impedance of the output signal (only used for electric instruments such as guitar and bass) using a 1:1 amplifier to prevent signal loss and degradation.

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The power supply of this device will utilize the USB-C port of the MCU, while also using a battery charging circuit to store energy in a Li-ion or LiPo battery for extended use.