LED Matrix Metronome

1#include <Wire.h>
2#include <Adafruit_GFX.h>
3#include "Adafruit_LEDBackpack.h"
4
5//  LED matrix object
6Adafruit_BicolorMatrix matrix = Adafruit_BicolorMatrix();
7
8//  variables associated with to ptm switch
9const int switchPin = 2;
10int switchState  = 0;
11
12// variables associated with potentiometer + smoothing
13const int  numReadings = 10;
14double potReadings[numReadings];
15int readIndex = 0;
16int  potTotal = 0;
17int potAverage = 0;
18
19//variables associated with time keeping
20int  state = 0;
21unsigned long previousTime = 0;
22int interval;
23
24// variables  determining display pattern 
25// 4/4
26const int x0[] = {0,0,4,4,0,0,4,4,0,0,4,4,0,0,4,4};
27const  int y0[] = {0,4,4,0,0,4,4,0,0,4,4,0,0,4,4,0};
28const int z0[] = {2,2,2,2,3,3,3,3,1,1,1,1,0,0,0,0};
29const  int w0[] = {4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4};
30const int h0[] = {4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4};
31
32//  3/4
33const int x1[] = {2,0,4,2,0,4,2,0,4,2,0,4};
34const int y1[] = {0,4,4,0,4,4,0,4,4,0,4,4};
35const  int z1[] = {2,2,2,3,3,3,1,1,1,0,0,0};
36const int w1[] = {4,4,4,4,4,4,4,4,4,4,4,4};
37const  int h1[] = {4,4,4,4,4,4,4,4,4,4,4,4};
38
39// 6/8
40const int x2[] = {0,0,4,4,0,0,0,0,4,4,0,0};
41const  int y2[] = {4,0,4,0,4,0,4,0,4,0,4,0};
42const int z2[] = {1,1,1,3,3,3,2,2,2,0,0,0};
43const  int w2[] = {4,8,4,4,8,4,4,8,4,4,8,4};
44const int h2[] = {4,4,4,4,4,4,4,4,4,4,4,4};
45
46//  pointers to current display pattern 
47const int *xp = x0;
48const int *yp = y0;
49const  int *zp = z0;
50const int *wp = w0;
51const int *hp = h0;
52
53// number of  iterations of display pattern
54int stateLimit = 16;
55
56// default and number  of display patterns 
57int TimeSig = 0;
58int TimeSigLimit = 3;
59
60//variables  associated with piezo 
61const int piezoPin = 8;
62int modulo = 4; // accent the  first beat of the bar 
63
64
65void setup() {
66  Serial.begin(9600);
67  Serial.println("8x8  LED Matrix Test");
68  
69  matrix.begin(0x70);  // pass in the address
70  matrix.setRotation(3);  // rotate so pins are at 0th row 
71  
72  pinMode(switchPin, INPUT);
73  
74  // initialise all pot readings to 0
75  for (int thisReading = 0; thisReading  < numReadings; thisReading++) {
76    potReadings[thisReading] = 0;
77  } 
78}
79
80
81void  loop() {
82  
83  //potentiometer smoothing 
84  potTotal = potTotal - potReadings[readIndex];  //subtract the last reading 
85  potReadings[readIndex] = analogRead(A0); 
86  potTotal = potTotal + potReadings[readIndex]; //add current reading to total 
87  readIndex = readIndex + 1; //advance to next position in array 
88  // if we're  at the end of the array...
89  if (readIndex >= numReadings) {
90    // ...wrap  around to the beginning:
91    readIndex = 0;
92  }
93  potAverage = sqrt(potTotal/numReadings)  * 100; //take the square root to get a non linear tempo response, multiply by 100  to increase the sensitivity of map (which can only handle integers). 
94  delay(1);  // delay in between reads for stability 
95
96  // map the pot average to an interval  (bpm = 1000/interval * 60). 
97  interval = map(potAverage,0,3200,1500,200); //bpm  can be set between 45bpm (1500 ms interval) and 300bpm (200ms interval). Must be  mapped in reverse to encode non linear tempo mapping. 
98  Serial.println(interval);
99
100  //check whether the button has been pressed to change time sig 
101  switchState  = digitalRead(switchPin);
102  if(switchState == HIGH){
103    // move to next time  signature
104    TimeSig += 1; 
105    // if the time signature limit is reached  go back to start 
106    if (TimeSig == TimeSigLimit){
107      TimeSig = 0;
108    }
109    // update the display pattern based on the time signature 
110    switch(TimeSig){
111    // 4/4
112    case 0:
113    xp = x0;
114    yp = y0;
115    zp = z0;
116    wp  = w0;
117    hp = h0;
118    stateLimit = 16;
119    modulo = 4;
120    break;
121    // 3/4
122    case 1:
123    xp = x1;
124    yp = y1;
125    zp = z1;
126    wp  = w1;
127    hp = h1;
128    stateLimit = 12;
129    modulo = 3;
130    break;
131    // 6/8
132    case 2:
133    xp = x2;
134    yp = y2;
135    zp = z2;
136    wp  = w2;
137    hp = h2;
138    stateLimit = 12;
139    modulo = 6;
140    break;
141    }  
142    // reset the state counter 
143    state = 0;
144    // clear the  display
145    matrix.clear();
146    matrix.writeDisplay();
147    // delay to  allow button time to unpress
148    delay(250);
149  }
150
151  // update matrix  with new pattern 
152  matrix.fillRect(xp[state],yp[state],wp[state],hp[state],zp[state]);
153
154  //how much time has passed since the last beat?
155  unsigned long currentTime  = millis();
156  
157  // if is time for the next beat
158  if (currentTime - previousTime  > interval){
159    // reset time keeping
160    previousTime = currentTime;
161    // update matrix display
162    matrix.writeDisplay();
163    // if is the first  beat of the bar play tone an octave higher (A at 880hz)
164    if(state % modulo  == 0){
165      tone(piezoPin,880,20);
166    }
167    // else play an A at 440  hz
168    else{
169      tone(piezoPin,440,20);
170    }
171    // increase state
172    state += 1; 
173    // reset state to 0 once it has reached state limit
174    if(state == stateLimit){
175      state = 0;
176    }
177  }
178}
179