The code below is the Ampli-Tie modification. It does not use a peak dot. With my microphone, I had noise issues, so the noise level is rather high. You can adjust values in the code to suit your project.
/* LED "Color Organ" for Adafruit Trinket and NeoPixel LEDs.
Hardware requirements:
- Adafruit Trinket or Gemma mini microcontroller (ATTiny85).
- Adafruit Electret Microphone Amplifier (ID: 1063)
- Several Neopixels, you can mix and match
o Adafruit Flora RGB Smart Pixels (ID: 1260)
o Adafruit NeoPixel Digital LED strip (ID: 1138)
o Adafruit Neopixel Ring (ID: 1463)
Software requirements:
- Adafruit NeoPixel library
Connections:
- 5 V to mic amp +
- GND to mic amp -
- Analog pinto microphone output (configurable below)
- Digital pin to LED data input (configurable below)
Written by Adafruit Industries. Distributed under the BSD license.
This paragraph must be included in any redistribution.
*/
#include <Adafruit_NeoPixel.h>
#include <avr/power.h>
#define N_PIXELS 19 // Number of pixels you are using
#define MIC_PIN 1 // Microphone is attached to Trinket GPIO #2/Gemma D2 (A1)
#define LED_PIN 0 // NeoPixel LED strand is connected to GPIO #0 / D0
#define DC_OFFSET 0 // DC offset in mic signal - if unusure, leave 0
#define NOISE 100 // Noise/hum/interference in mic signal
#define SAMPLES 60 // Length of buffer for dynamic level adjustment
#define TOP (N_PIXELS +1) // Allow dot to go slightly off scale
// Comment out the next line if you do not want brightness control or have a Gemma
#define POT_PIN 3 // if defined, a potentiometer is on GPIO #3 (A3, Trinket only)
byte
peak = 0, // Used for falling dot
dotCount = 0, // Frame counter for delaying dot-falling speed
volCount = 0; // Frame counter for storing past volume data
int
vol[SAMPLES], // Collection of prior volume samples
lvl = 10, // Current "dampened" audio level
minLvlAvg = 0, // For dynamic adjustment of graph low & high
maxLvlAvg = 512;
Adafruit_NeoPixel strip = Adafruit_NeoPixel(N_PIXELS, LED_PIN, NEO_GRB + NEO_KHZ800);
void setup() {
// This is the auto-speed doubler line, keep it in, it will
// automatically double the speed when 16Mhz is selected!
if (F_CPU == 16000000) clock_prescale_set(clock_div_1);
memset(vol, 0, sizeof(vol));
strip.begin();
}
void loop() {
uint8_t i;
uint16_t minLvl, maxLvl;
int n, height;
n = analogRead(MIC_PIN); // Raw reading from mic
n = abs(n - 512 - DC_OFFSET); // Center on zero
n = (n <= NOISE) ? 0 : (n - NOISE); // Remove noise/hum
lvl = ((lvl * 7) + n) >> 3; // "Dampened" reading (else looks twitchy)
// Calculate bar height based on dynamic min/max levels (fixed point):
height = TOP * (lvl - minLvlAvg) / (long)(maxLvlAvg - minLvlAvg);
if(height < 0L) height = 0; // Clip output
else if(height > TOP) height = TOP;
if(height > peak) peak = height; // Keep 'peak' dot at top
// if POT_PIN is defined, we have a potentiometer on GPIO #3 on a Trinket
// (Gemma doesn't have this pin)
uint8_t bright = 255;
#ifdef POT_PIN
bright = analogRead(POT_PIN); // Read pin (0-255) (adjust potentiometer
// to give 0 to Vcc volts
#endif
strip.setBrightness(bright); // Set LED brightness (if POT_PIN at top
// define commented out, will be full)
// Color pixels based on rainbow gradient
for(i=0; i<N_PIXELS; i++) {
if(i >= height)
strip.setPixelColor(i, 0, 0, 0);
else
strip.setPixelColor(i,Wheel(map(i,0,strip.numPixels()-1,30,150)));
}
strip.show(); // Update strip
vol[volCount] = n; // Save sample for dynamic leveling
if(++volCount >= SAMPLES) volCount = 0; // Advance/rollover sample counter
// Get volume range of prior frames
minLvl = maxLvl = vol[0];
for(i=1; i<SAMPLES; i++) {
if(vol[i] < minLvl) minLvl = vol[i];
else if(vol[i] > maxLvl) maxLvl = vol[i];
}
// minLvl and maxLvl indicate the volume range over prior frames, used
// for vertically scaling the output graph (so it looks interesting
// regardless of volume level). If they're too close together though
// (e.g. at very low volume levels) the graph becomes super coarse
// and 'jumpy'...so keep some minimum distance between them (this
// also lets the graph go to zero when no sound is playing):
if((maxLvl - minLvl) < TOP) maxLvl = minLvl + TOP;
minLvlAvg = (minLvlAvg * 63 + minLvl) >> 6; // Dampen min/max levels
maxLvlAvg = (maxLvlAvg * 63 + maxLvl) >> 6; // (fake rolling average)
}
// Input a value 0 to 255 to get a color value.
// The colors are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
if(WheelPos < 85) {
return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
} else if(WheelPos < 170) {
WheelPos -= 85;
return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
} else {
WheelPos -= 170;
return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
}
}
Page last edited October 07, 2013
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