【Arduino 动手做】8x32 矩阵上的Arduino FFT音频频谱分析仪
这是一个非常简单，但在视觉上仍然非常有效的项目，可以用作桌面上的一个小工具。频谱分析仪将信号幅度显示为频率的函数，使工程师和技术人员能够可视化和分析信号特性。特别是，音频分析仪在频域中对声学信号进行可视化表示，其中信号的频率显示在 x 轴上，而某个频率的幅度显示在 y 轴上。在我之前的几个视频中，我介绍了几种不同类型的此类设备，但这次是第一次使用 FHT Arduino 库。此库比常用的 FFT 库快几倍，但以牺牲速度为代价，音频范围的两端会出现一定的分辨率和精度损失。
但是，在特定情况下，我们不必开发测量仪器，而是开发一个简单的小工具，我们不需要极高的精度，我们只需要以音乐节奏打开几个 LED。
顺便说一句，该项目已由昵称为 januks 的用户提交给 Arduino 项目中心，实际上是 Shaajeb 出色的 Spectrum analajzer 项目的返工。我根据我的想法和要求对硬件和代码进行了最少的修改。
该设备的构建非常简单，并且仅包含几个组件：
Arduino Nano MCU 板，
8x64 色 LED 矩阵，带 WS2812B 个可寻址 LED
两 （3） 个触摸按钮
三个电阻器和一个电容器
现在让我们看看该设备在实际条件下是如何工作的。
考虑到它非常简单，该设备无需任何先前设置即可立即工作。一个按钮用于分 7 个步骤调整 LED 光强度。使用另一个按钮，我们可以浏览具有特定颜色集的 6 个不同的 mod，我们还可以添加更多，对代码进行非常小的修改。
接下来，我们来测试一下这个分析器覆盖的频率范围。为此，我们将使用一个简单的在线音调生成器。如您所见，该设备覆盖了从 20 赫兹到 20 kHz 的整个听力范围。这种大范围设备在用于视觉 FFT 分析时非常出色，但在呈现音乐材料时有一个实际的缺点。
也就是说，该音乐信号的很大一部分（可能是 90%）在高达 10Khz 的范围内，只有一小部分属于更高的频率。这实际上意味着，在发出音乐信号的整个过程中，分析器的最右侧部分将处于非活动状态。让我们看看它在实践中是什么样子（这是一个语音信号的例子，所以我们也将尝试用音乐素材来做）。正如我在开头提到的，由于这是一个视觉装饰性添加，而不是一个精确的测量仪器，因此最好将带宽减少一半，实际上减少到 10 千赫兹。
对于这种情况，我在代码中进行了一些修改，但也希望在 input 上设置一个简单的 Low-pass filter。让我们在输入端使用在线音调生成器来测试范围。范围高达 10Khz。
现在，在本例中，矩阵已完全填充，视觉上看起来要好得多。至于设备的外观，我试图制作一个由 PVC 板和玻璃制成的简单但仍然实用的版本，厚度为 4 毫米。
最后是一个简短的结论。
这是一个非常简单的项目，专为初学者设计，但在视觉上仍然非常有效，可以作为桌面上的小工具，也可以作为音频设备的补充。它也可以用作简单的学校 FFT 频谱分析仪仪器，用于教育目的。
【Arduino 动手做】8x32 矩阵上的Arduino FFT音频频谱分析仪
项目代码/*
Copyright (c) 2020 Janux
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
Based on an original project for the MAX72xx LED matrix and FFT lib made from Shajeeb.
Configuration settings section based on work of Ragnar Ranøyen Homb from Norvegian Creation.
*/
#define LIN_OUT 1 //FHT linear output magnitude
#define FHT_N 128 //set SAMPLES for FHT, Must be a power of 2
#include <FHT.h>
#define xres 32 //Total number of columns in the display, must be <= SAMPLES/2
#define yres 8 //Total number of rows in the display
#define ledPIN 6 //out pint to control Leds
#define NUM_LEDS (xres * yres)//total leds in Matrix
#include <Adafruit_NeoPixel.h>
#include <Adafruit_NeoMatrix.h>
#define colorPIN 5 //pin to change ledcolor
#define brightnessPIN 10//pin to change brightness
byte displaycolor = 0; //default color value
byte brightness = 1; //default brightness level
#include <EEPROM.h>
#define CONFIG_START 32 //Memory start location
#define CONFIG_VERSION "VER01"//Config version configuration
typedef struct {
char version;
byte displaycolor;
byte brightness;
} configuration_type;
configuration_type CONFIGURATION = {
CONFIG_VERSION,
displaycolor,
brightness
};
byte yvalue;
int peaks;
byte state = HIGH; // the current reading from the input pin
byte previousState = LOW; // the previous reading from the input pin
unsigned long lastDebounceTime = 0; // the last time the output pin was toggled
unsigned long debounceDelay = 100; // the debounce time; increase if the output flickers
byte data_avgs; //Array for samplig
// Parameter 1 = number of leds in matrix
// Parameter 2 = pin number
// Parameter 3 = pixel type flags, add together as needed:
// NEO_KHZ800800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
// NEO_KHZ400 400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
// NEO_GRB Pixels are wired for GRB bitstream (most NeoPixel products)
// NEO_RGB Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
Adafruit_NeoPixel pixel = Adafruit_NeoPixel(NUM_LEDS, ledPIN, NEO_GRB + NEO_KHZ800);
// EQ filter
byte eq = {
60, 65, 70, 75, 80, 85, 90, 95,
100, 100, 100, 100, 100, 100, 100, 100,
100, 100, 100, 100, 100, 100, 100, 100,
115, 125, 140, 160, 185, 200, 200, 200
};
bool EQ_ON = true; // set to false to disable eq
//Define 5 set of colors for leds, 0 for single custom color
byte colors[] = {
{170, 160, 150, 140, 130, 120, 1, 1},
{1, 5, 10, 15, 20, 25, 90, 90},
{90, 85, 80, 75, 70, 65, 1, 1},
{90, 90, 90, 30, 30, 30, 1, 1},
{170, 160, 150, 140, 130, 120, 110, 0}
};
//Define chars for display settings
byte charBitmap[] = {
0x1C, 0x10, 0x10, 0x10, 0x10, 0x1C, 0x08, 0x18, 0x08, 0x08, 0x08, 0x1C,
0x0C, 0x12, 0x04, 0x08, 0x10, 0x1E, 0x0C, 0x12, 0x02, 0x06, 0x12, 0x0C,
0x10, 0x10, 0x10, 0x14, 0x1E, 0x04, 0x1E, 0x10, 0x1E, 0x02, 0x12, 0x0C,
0x1E, 0x10, 0x10, 0x1E, 0x12, 0x1E, 0x1E, 0x02, 0x04, 0x08, 0x08, 0x08,
0x0C, 0x12, 0x0C, 0x12, 0x12, 0x0C, 0x1C, 0x12, 0x1C, 0x12, 0x12, 0x1C
};
void setup() {
pixel.begin(); //initialize Led Matrix
//Begin FFT operations
ADCSRA = 0b11100101; // set ADC to free running mode and set pre-scaler to 32 (0xe5)
ADMUX =0b00000000; // use pin A0 and external voltage reference
// Read config data from EEPROM
if (loadConfig()) {
displaycolor = CONFIGURATION.displaycolor;
brightness = CONFIGURATION.brightness;
}
//Set brightness loaded from EEPROM
pixel.setBrightness(brightness * 24 + 8);
//Show current config on start
//change true to false if you don't want this
showSettings(3, true);
}
void loop() {
while (1) { // reduces jitter
Sampling(); // FHT Library use only one data array
RearrangeFHT(); // re-arrange FHT result to match with no. of display columns
SendToDisplay(); // send to display according measured value
colorChange(); // check if button pressed to change color
brightnessChange();// check if button pressed to change brightness
delay(10); // delay to reduce flickering (FHT is too fast :D)
}
}
void Sampling() {
for (int i = 0; i < FHT_N; i++) {
while (!(ADCSRA & 0x10)); // wait for ADC to complete current conversion ie ADIF bit set
ADCSRA = 0b11110101 ; // clear ADIF bit so that ADC can do next operation (0xf5)
//ADLAR bit is 0, so the 10 bits of ADC Data registers are right aligned
byte m = ADCL; // fetch adc data
byte j = ADCH;
int value = (j << 8) | m; // form into an int
value -= 0x0200; // form into a signed int
value <<= 6; // form into a 16b signed int
fht_input = value / 8; // copy to fht input array after compressing
}
// ++ begin FHT data process -+-+--+-+--+-+--+-+--+-+--+-+--+-+-
fht_window(); // window the data for better frequency response
fht_reorder(); // reorder the data before doing the fht
fht_run(); // process the data in the fht
fht_mag_lin(); // take the output of the fht
}
void RearrangeFHT() {
// FHT return real value unsing only one array
// after fht_mag_lin() calling the samples value are in
// the first FHT_N/2 position of the array fht_lin_out[]
int step = (FHT_N / 2) / xres;
int c = 0;
for (int i = 0; i < (FHT_N / 2); i += step) {
data_avgs = 0;
for (int k = 0 ; k < step ; k++) {
data_avgs = data_avgs + fht_lin_out;// linear output magnitude
}
data_avgs = data_avgs / step ; // save avgs value
c++;
}
}
void SendToDisplay() {
for (int i = 0; i < xres; i++) {
if (EQ_ON)
data_avgs = data_avgs * (float)(eq) / 100; // apply eq filter
data_avgs = constrain(data_avgs, 0, 80); // set max & min values for buckets to 0-80
data_avgs = map(data_avgs, 0, 80, 0, yres); // remap averaged values to yres 0-8
yvalue = data_avgs;
peaks = peaks - 1; // decay by one light
if (yvalue > peaks) peaks = yvalue; // save peak if > previuos peak
yvalue = peaks; // pick peak to display
setColumn(i, yvalue); // draw columns
}
pixel.show(); // show column
}
// Light up leds of x column according to y value
void setColumn(byte x, byte y) {
int led, i;
for (i = 0; i < yres; i++) {
led = GetLedFromMatrix(x, i); //retrieve current led by x,y coordinates
if (peaks > i) {
switch (displaycolor) {
case 4:
if (colors == 0) {
// show custom color with zero value in array
pixel.setPixelColor(led, 255, 255, 255); //withe
}
else {
// standard color defined in colors array
pixel.setPixelColor(led, Wheel(colors));
}
break;
case 5:
//change color by column
pixel.setPixelColor(led, Wheel(x * 16));
break;
case 6:
//change color by row
pixel.setPixelColor(led, Wheel(i * y * 3));
break;
case 7:
//change color by... country :D
//Italy flagh
//if (x < 11) pixel.setPixelColor(led, 0, 255, 0);
//if (x > 10 && x < 21) pixel.setPixelColor(led, 255, 255, 255);
//if (x > 20) pixel.setPixelColor(led, 255, 0, 0);
//stars and stripes
if (i < yres - 2) {
if (x & 0x01) {
pixel.setPixelColor(led, 0, 0, 255);
}
else {
pixel.setPixelColor(led, 255, 0, 0);
}
}
else {
pixel.setPixelColor(led, 255, 255, 255);
}
break;
default:
//display colors defined in color array
pixel.setPixelColor(led, Wheel(colors));
} //END SWITCH
}
else {
//Light off leds
pixel.setPixelColor(led, pixel.Color(0, 0, 0));
}
}
}
//================================================================
// Calculate a led number by x,y coordinates
// valid for WS2812B with serpentine layout placed in horizzontal
// and zero led at bottom right (DIN connector on the right side)
// input value: x= 0 to xres-1 , y= 0 to yres-1
// return a led number from 0 to NUM_LED
//================================================================
int GetLedFromMatrix(byte x, byte y) {
int led;
x = xres - x - 1;
if (x & 0x01) {
//Odd columns increase backwards
led = ((x + 1) * yres - y - 1);
}
else {
//Even columns increase normally
led = ((x + 1) * yres - yres + y);
}
return constrain(led, 0, NUM_LEDS);
}
//================================================================
void colorChange() {
int reading = digitalRead(colorPIN);
if (reading == HIGH && previousState == LOW && millis() - lastDebounceTime > debounceDelay) {
displaycolor++;
if (displaycolor > 7) displaycolor = 0;
showSettings(1, true); //set to false if you don't want this
saveConfig();
lastDebounceTime = millis();
}
previousState = reading;
}
void brightnessChange() {
int reading = digitalRead(brightnessPIN);
if (reading == HIGH && previousState == LOW && millis() - lastDebounceTime > debounceDelay) {
brightness++;
if (brightness > 7) brightness = 0;
pixel.setBrightness(brightness * 24 + 8);
showSettings(2, true); //set to false if you don't want this
saveConfig();
lastDebounceTime = millis();
}
previousState = reading;
}
// Utility from Adafruit Neopixel demo sketch
// Input a value 0 to 255 to get a color value.
// The colours are a transition R - G - B - back to R.
unsigned long Wheel(byte WheelPos) {
WheelPos = 255 - WheelPos;
if (WheelPos < 85) {
return pixel.Color(255 - WheelPos * 3, 0, WheelPos * 3);
}
if (WheelPos < 170) {
WheelPos -= 85;
return pixel.Color(0, WheelPos * 3, 255 - WheelPos * 3);
}
WheelPos -= 170;
return pixel.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
}
// load whats in EEPROM in to the local CONFIGURATION if it is a valid setting
int loadConfig() {
if (EEPROM.read(CONFIG_START + 0) == CONFIG_VERSION &&
EEPROM.read(CONFIG_START + 1) == CONFIG_VERSION &&
EEPROM.read(CONFIG_START + 2) == CONFIG_VERSION &&
EEPROM.read(CONFIG_START + 3) == CONFIG_VERSION &&
EEPROM.read(CONFIG_START + 4) == CONFIG_VERSION) {
// load (overwrite) the local configuration struct
for (unsigned int i = 0; i < sizeof(CONFIGURATION); i++) {
*((char*)&CONFIGURATION + i) = EEPROM.read(CONFIG_START + i);
}
return 1; // return 1 if config loaded
}
return 0; // return 0 if config NOT loaded
}
// save the CONFIGURATION in to EEPROM
void saveConfig() {
CONFIGURATION.displaycolor = displaycolor;
CONFIGURATION.brightness = brightness;
for (unsigned int i = 0; i < sizeof(CONFIGURATION); i++)
EEPROM.write(CONFIG_START + i, *((char*)&CONFIGURATION + i));
}
// 1 display color level, 2 display brightness level, 3 both
void showSettings(byte num, bool show) {
if (show) {
pixel.clear();
if (num == 1 || num == 3) {
drawChar(0, 0);
drawChar(displaycolor + 1, 5);
}
if (num == 2 || num == 3) {
drawChar(9, xres - 9);
drawChar(brightness + 1, xres - 4);
}
delay(1000);
pixel.clear();
}
}
// Draw custom chars
void drawChar(byte val, byte pos) {
for (int x = 4; x >= 0; x--) {
for (int y = 5; y >= 0; y--) {
if ((charBitmap >> x) & 0x01) {
pixel.setPixelColor(GetLedFromMatrix(4 - x + pos, y + 1), Wheel((pos > 10) * 170));
pixel.show();
}
}
}
}
【Arduino 动手做】8x32 矩阵上的Arduino FFT音频频谱分析仪
【Arduino 动手做】8x32 彩色矩阵 WS2812B 上的 Arduino FFT 音频频谱分析仪项目链接：https://www.hackster.io/mircemk/arduino-fft-audio-spectrum-analyzer-on-8x32-color-matrix-ws2-e03947
项目作者：北马其顿 米尔塞姆克（Mirko Pavleski）
项目视频 ：https://www.youtube.com/watch?v=KmDTCp0HBVQ
项目代码：
https://www.hackster.io/code_files/652986/download
https://www.hackster.io/code_files/652987/download
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