采用MAX7219四合一点阵模块 对声音频率为100 在点阵上显示频谱 的代码
时间: 2023-06-15 10:06:02 浏览: 53
这里给出一个基于Arduino平台的代码实现。需要注意的是,这个代码只是一个简单的示例,需要根据具体硬件和需求进行适当的修改和调整。
```c++
#include <LedControl.h>
// 定义MAX7219四合一点阵模块引脚
#define DIN_PIN 12
#define CS_PIN 11
#define CLK_PIN 10
// 定义采样窗口大小和频率分辨率
#define SAMPLE_WINDOW_SIZE 64
#define FREQUENCY_RESOLUTION 100
// 定义分频系数
const int PRESCALER = 128;
// 定义采样计数器和样本数组
uint8_t sampleCounter = 0;
uint16_t samples[SAMPLE_WINDOW_SIZE];
// 初始化MAX7219点阵模块
LedControl lc = LedControl(DIN_PIN, CLK_PIN, CS_PIN, 1);
void setup() {
// 设置串口通信速率
Serial.begin(9600);
// 初始化MAX7219点阵模块
lc.shutdown(0, false);
lc.setIntensity(0, 15);
lc.clearDisplay(0);
}
void loop() {
// 采样音频信号
uint16_t sample = analogRead(A0);
sample = sample >> 2;
// 取平方得到功率
sample *= sample;
// 存储样本
samples[sampleCounter] = sample;
// 计数器递增
sampleCounter++;
// 检查样本数组是否已满
if (sampleCounter >= SAMPLE_WINDOW_SIZE) {
// 处理采样
processSamples();
// 重置计数器和样本数组
sampleCounter = 0;
for (int i = 0; i < SAMPLE_WINDOW_SIZE; i++) {
samples[i] = 0;
}
}
}
// 处理采样
void processSamples() {
// 计算FFT
double real[SAMPLE_WINDOW_SIZE];
double imag[SAMPLE_WINDOW_SIZE];
for (int i = 0; i < SAMPLE_WINDOW_SIZE; i++) {
real[i] = samples[i];
imag[i] = 0.0;
}
FFT(real, imag, SAMPLE_WINDOW_SIZE);
// 计算频率和幅值
double frequencies[SAMPLE_WINDOW_SIZE / 2];
double amplitudes[SAMPLE_WINDOW_SIZE / 2];
for (int i = 0; i < SAMPLE_WINDOW_SIZE / 2; i++) {
frequencies[i] = (double)i * FREQUENCY_RESOLUTION / SAMPLE_WINDOW_SIZE;
amplitudes[i] = sqrt(real[i] * real[i] + imag[i] * imag[i]) / SAMPLE_WINDOW_SIZE;
}
// 在点阵上显示频谱
int column = 0;
for (int i = 1; i < SAMPLE_WINDOW_SIZE / 2; i++) {
double frequency = frequencies[i];
double amplitude = amplitudes[i];
int row = (int)(amplitude * 8);
if (row > 7) {
row = 7;
}
lc.setLed(0, row, column, true);
if (column < 7) {
column++;
}
}
}
// FFT实现
void FFT(double* real, double* imag, uint16_t n) {
// 计算复数单位根
double pi = 3.14159265358979323846;
double theta = 2 * pi / n;
double wReal = cos(theta);
double wImag = sin(theta);
// 计算蝴蝶因子
double wStepReal, wStepImag;
wStepReal = 1.0;
wStepImag = 0.0;
double tempReal, tempImag;
for (int i = 0; i < n / 2; i++) {
double theta = -2 * pi * i / n;
wStepReal = cos(theta);
wStepImag = sin(theta);
tempReal = wStepReal * real[i + n / 2] - wStepImag * imag[i + n / 2];
tempImag = wStepReal * imag[i + n / 2] + wStepImag * real[i + n / 2];
real[i + n / 2] = real[i] - tempReal;
imag[i + n / 2] = imag[i] - tempImag;
real[i] += tempReal;
imag[i] += tempImag;
tempReal = wStepReal * wStepReal - wStepImag * wStepImag;
tempImag = 2 * wStepReal * wStepImag;
wStepReal = tempReal;
wStepImag = tempImag;
}
// 递归计算FFT
if (n > 2) {
FFT(real, imag, n / 2);
FFT(real + n / 2, imag + n / 2, n / 2);
}
}
```
该代码中主要的实现步骤包括:
1. 初始化MAX7219点阵模块;
2. 采样音频信号,存储样本;
3. 当样本数组满时,处理采样,计算FFT,计算频率和幅值;
4. 在点阵上显示频谱。
需要注意的是,该代码中的FFT实现使用了递归方式,可能会存在效率问题,具体实现方式可以根据需要进行修改。此外,需要根据具体的硬件和需求进行适当的调整和优化。