/*------------------------------------------------------------------------------
02/11/2020
Author: Cisco • A C R O B O T I C
Platforms: ESP32
Language: C++/Arduino
File: vu_meter.ino
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Description:
Code for YouTube video tutorial demonstrating how to build a Volume Unit (VU)
meter using an ESP32, a pair of NeoPixel/WS2812B LED sticks, and a MAX9814 mic.
The audio signal is read from the mic, and a set of LEDs proportional to the
amplitude lights up using a wide range of colors:
https://youtu.be/xvG_kvhBECc
------------------------------------------------------------------------------
Do you like my work? You can support me:
https://patreon.com/acrobotic
https://paypal.me/acrobotic
https://buymeacoff.ee/acrobotic
------------------------------------------------------------------------------
Please consider buying products and kits to help fund future Open-Source
projects like this! We'll always put our best effort in every project, and
release all our design files and code for you to use.
https://acrobotic.com/
https://amazon.com/shops/acrobotic
------------------------------------------------------------------------------
License:
Please see attached LICENSE.txt file for details.
------------------------------------------------------------------------------*/
#include<FastLED.h>
#include<MegunoLink.h>
#include<Filter.h>
// define necessary parameters
#define N_PIXELS 30 //led灯珠数量
#define MIC_PIN A0 //音频采集模块接口
#define LED_PIN 6 //led灯带接口
// the following parameters can be tweaked according to your audio levels
#define NOISE 500
#define TOP (N_PIXELS+2) // allow the max level to be slightly off scale
#define LED_TYPE WS2811
#define BRIGHTNESS 100 // a little dim for recording purposes
#define COLOR_ORDER GRB
// declare the LED array
CRGB leds[N_PIXELS];
// define the variables needed for the audio levels
int lvl = 0, minLvl = 0, maxLvl = 40; // tweak the min and max as needed
// instantiate the filter class for smoothing the raw audio signal
ExponentialFilter<long> ADCFilter(5,0);
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
// initialize the LED object
FastLED.addLeds<LED_TYPE,LED_PIN,COLOR_ORDER>(leds,N_PIXELS).setCorrection(TypicalLEDStrip);
FastLED.setBrightness(BRIGHTNESS);
}
void loop() {
// put your main code here, to run repeatedly:
// read the audio signal and filter it
int n, height;
n = analogRead(MIC_PIN);
// remove the MX9614 bias of 1.25VDC
n = abs(1023 - n);
// hard limit noise/hum
//n = (n <= NOISE) ? 0 : abs(n - NOISE);
// apply the exponential filter to smooth the raw signal
ADCFilter.Filter(n);
lvl = ADCFilter.Current()-743;
// plot the raw versus filtered signals
//Serial.println(n);
//Serial.print(" ");
Serial.println(lvl);
// calculate the number of pixels as a percentage of the range
// TO-DO: can be done dynamically by using a running average of min/max audio levels
height = TOP * (lvl - minLvl) / (long)(maxLvl - minLvl);
if(height < 0L) height = 0;
else if(height > TOP) height = TOP;
// turn the LEDs corresponding to the level on/off
for(uint8_t i = 0; i < N_PIXELS; i++) {
// turn off LEDs above the current level
if(i >= height) leds[i] = CRGB(0,0,0);
// otherwise, turn them on!
else leds[i] = Wheel( map( i, 0, N_PIXELS-1, 30, 150 ) );
}
FastLED.show();
}
CRGB Wheel(byte WheelPos) {
delay(5);
// return a color value based on an input value between 0 and 255
if(WheelPos < 85)
return CRGB(WheelPos * 3, 255 - WheelPos * 3, 0);
else if(WheelPos < 170) {
WheelPos -= 85;
return CRGB(255 - WheelPos * 3, 0, WheelPos * 3);
} else {
WheelPos -= 170;
return CRGB(0, WheelPos * 3, 255 - WheelPos * 3);
}
}
