32 频段 Arduino 音频频谱分析仪：线性与伪对数双模式

零部件与物料

所需工具

• 电烙铁

软件与在线服务

• Arduino IDE

项目简介

作者首个 Arduino 音频电子项目。参考 Shajeeb 的音频可视化器，扩展为 32 频段线性模式与 11 频段伪对数模式。在 Excel 建立自定义对数映射表烧录固件，按键切换显示模式，适合表演或实验现场切换。

欢迎魔改固件/硬件适配你的创意项目。

源代码

32_Band_LED_Spectrum_Analyzer-009.ino

// Modified by Christian Suryanto, based on (c) 2019 Shajeeb TM // HAZI TECH
#include <arduinoFFT.h>
#include <MD_MAX72xx.h>
#include <SPI.h>
#include <EEPROM.h>

#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
#define CLK_PIN 13
#define DATA_PIN 11
#define CS_PIN 10
#define SAMPLES 64
#define MAX_DEVICES 4
#define xres 32
#define yres 8
#define PREV 0xFF02FD
#define NEXT 0xFFC23D
#define PWR 0xFFA25D

int audio_response = 35;
double vReal[SAMPLES];
double vImag[SAMPLES];
char data_avgs[xres];
int yvalue, displaycolumn, displayvalue;
int peaks[xres];
const int buttonPin = 6;
int state = HIGH, previousState = LOW, displaymode;
unsigned long lastDebounceTime = 0, debounceDelay = 50;
int MY_ARRAY[] = {0, 128, 192, 224, 240, 248, 252, 254, 255};
bool EQ_ON = true;
byte eq1[32] = {40, 45, 50, 60, 65, 70, 75, 95, 110, 110, 110, 110, 110, 110, 110, 110, 130, 130, 130, 130, 130, 130, 130, 130, 145, 155, 170, 180, 215, 220, 245, 255};
byte eq2[11] = {40, 70, 75, 110, 110, 140, 145, 220, 220, 230, 250};

MD_MAX72XX mx = MD_MAX72XX(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);
arduinoFFT FFT = arduinoFFT();

void setup() {
  EEPROM.update(1,1);
  displaymode = EEPROM.read(1);
  ADCSRA = 0b11100101; // ADC 预分频 32，自由运行
  ADMUX = 0b00000000;  // 参考 AVCC，通道 0
  pinMode(buttonPin, INPUT);
  mx.begin();
  mx.control(MD_MAX72XX::INTENSITY, 0);
  delay(50);
}

void loop() {
  int numData; double rSum;
  for (int i=0; i peaks[i]) peaks[i] = yvalue;
    yvalue = peaks[i];
    displayvalue = MY_ARRAY[yvalue];
    if (displaymode == 1) {
      displaycolumn = 31 - i;
      mx.setColumn(displaycolumn, displayvalue);
    } else {
      displaycolumn = 31 - (3*i);
      mx.setColumn(displaycolumn-1, displayvalue);
      mx.setColumn(displaycolumn, displayvalue);
    }
  }
  displayModeChange();
}

void displayModeChange() {
  int reading = digitalRead(buttonPin);
  if (reading == HIGH && previousState == LOW && millis() - lastDebounceTime > debounceDelay) {
    if (displaymode == 1) {
      displaymode = 2; mx.clear(); delay(200); EEPROM.update(1,2);
    } else {
      displaymode = 1; mx.clear(); delay(200); EEPROM.update(1,1);
    }
    lastDebounceTime = millis();
  }
  previousState = reading;
}

原理图