Installing Arduino libraries is a frequent stumbling block. If this is your first time, or simply needing a refresher, please read the All About Arduino Libraries tutorial.
If the library is correctly installed (and the Arduino IDE is restarted), you should be able to navigate through the “File” rollover menus as follows:
File→Sketchbook→Libraries→Adafruit_NeoPixel→strandtest
// SPDX-FileCopyrightText: 2017 Limor Fried for Adafruit Industries
//
// SPDX-License-Identifier: MIT
#include <Adafruit_NeoPixel.h>
#define N_PIXELS 12 // Number of pixels you are using
#define MIC_PIN A1 // 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
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() {
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
// 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);
}
}
From the Tools→Board menu, select the device you are using:
- Adafruit Gemma M0
- Adafruit Gemma 8 MHz
Connect the USB cable between the computer and your device. The original Gemma (8 MHz) need the reset button pressed on the board, then click the upload button (right arrow icon) in the Arduino IDE. You do not need to press the reset on the newer Gemma M0.
When the battery is connected, you should get a light show from the LEDs. All your pixels working? Great! You can take apart this prototype and get ready to put the pixels in the collar. Refer to the NeoPixel Uberguide for more info.
Text editor powered by tinymce.
