This button is connected to one of the digital inputs and will be scanned every time the display is refreshed.Vivu Video is an application to create videos from photos and music with infinite customizable capabilities. Each time you press, the display mode will move to the next mode and finally reset to the default mode. Use the buttons here to change the display mode. You can easily modify/create different modes. The program has five display modes, which can basically be achieved by turning on / off the LEDs in different positions in each column. The amplitude of each frequency band is mapped between 0 and 8, depending on the amplitude corresponding to the number of LEDs in each column.
The library provides functions to turn on / off any number of LEDs in the column being used in the program. The MD_MAX72xx library makes display controls very easy. The display used in this project is a 32-column x 8-row LED matrix. But the 128 samples of the Arduino TFT library are very slow, so I stick to the best and highest 64 samples. The ArduinoFFT library can perform FFT on samples between 16 and 128, which can be configured in the program. The prototype is configured to take 64 samples and perform FFT on these samples. I found this library easy to use and provided the best accurate output for the project. The ArduinoFFT library is the core of the code, which converts the input analog signal into a frequency spectrum.
Audio spectrum visualizer program code#
The 512 caused by the DC offset is then subtracted from the code so that the reading represents the actual input signal change. With this DC bias, the ADC will produce 512 in the output even if the input signal is disconnected. Use two resistors R1 and R2 to divide the same 3.3V stable voltage, and then feed it into the analog input to obtain DC bias. This ensures that the ADC output does not limit the negative period of the input signal. When the analog signal oscillates above and below zero voltage level, we need to apply a DC bias to the analog input of the ADC. In this project, the reference voltage comes from a 3.3V stable voltage source on the Arduino board. The ADC is configured to use an external reference voltage. You can use an audio splitter cable to feed the same music to the spectrum analyzer and another amplifier (if needed). Therefore, the left and right audio channels are mixed together and fed into the A0 analog input of the ADC. The 38.64Khz sampling frequency means that digital sampling can reproduce up to 19.32Kz (Nyquist theorem) input frequency, which is enough to meet the requirements of audio signals.Īs I mentioned at the beginning, the intended purpose of the project is to display the spectrum of audio music signals. This can be achieved by configuring the ADC Prescaler to 32. The ADC is configured to sample the input signal at a clock frequency of 38.46khz.
The Arduino development board (ATmega328P) has a built-in analog-to-digital converter (ADC) that can be used to convert the input audio signal to digital samples.
The different voltages mentioned in the schematic are approximate and may be slightly different in your system. For the LED display power supply, it is powered by the 5v pin on the Arduino board. The Arduino development board can be powered through the USB port or 5v charger socket.
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