Clapping music with Arduino
This exercise relies on the following topics in C:
- variable types (int, char)
- character arrays (strings)
- loops
- nested loops
Hello world.c
Arduino is C!
#include <stdio.h>
main ()
{
printf("hello world\n");
}
Blink music
void setup() {
pinMode(8, OUTPUT);
for (int i=0; i<1000; i++) {
digitalWrite(8, HIGH);
delay(1);
digitalWrite(8, LOW);
delay(1);
}
}
void loop () {}
change the argument to the delay...
for my refined control, try delayMicroseconds
void setup() {
int x;
// initialize the digital pin as an output:
pinMode(8, OUTPUT);
for (int i=0; i<1000; i++) {
digitalWrite(8, HIGH);
delayMicroseconds(250);
digitalWrite(8, LOW);
delayMicroseconds(250);
}
}
void loop () {}
tone
- http://www.arduino.cc/en/Tutorial/Tone
- Starting point is the Example > Digital > toneMelody
Important: tone is a unique command in that it is asynchronous, meaning that when you call the function it starts playing the tone, but immediately returns control to your program. In Bash terms, it's like starting the program with the '&' character at the end -- the command runs "in the background". This is important to know, because you need to use the delay command to play consecutive tones, otherwise each call to tone undoes the previous ones.
So, the wrong way would be:
int speakerPin = 13;
void setup() {
tone(speakerPin, 500, 100);
tone(speakerPin, 600, 100);
tone(speakerPin, 700, 100);
tone(speakerPin, 800, 100);
tone(speakerPin, 900, 100);
}
void loop() {}
And the right way is instead:
int speakerPin = 13;
void setup() {
tone(speakerPin, 500, 100);
delay(100);
tone(speakerPin, 600, 100);
delay(100);
tone(speakerPin, 700, 100);
delay(100);
tone(speakerPin, 800, 100);
delay(100);
tone(speakerPin, 900, 100);
delay(100);
}
void loop() {}
Clapping music.c
Now, using a C string with the Clapping music pattern.
The clapping pattern might be imlemented using tone in the following way:
int speakerPin = 13;
int thedelay = 100;
char pat[] = "xxx xx x xx ";
int patlen = strlen(pat);
void setup() {}
void loop () {
if (pat[0] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[1] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[2] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[3] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[4] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[5] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[6] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[7] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[8] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[9] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[10] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
if (pat[11] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
delay(thedelay*10); // pause between repetitions
}
int speakerPin = 13;
int thedelay = 100;
char pat[] = "xxx xx x xx ";
int patlen = strlen(pat);
void setup()
{
}
void loop ()
{
int i = 0;
while (i<patlen) {
if (pat[i] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
i = i+1;
}
// the above could also be written in "shorthand" using the for statement...
/*
for (i=0; i<12; i+=1) {
if (pat[i] == 'x') tone(speakerPin, 400, 10);
delay(thedelay);
}
*/
delay(thedelay*10);
}
int speakerPin = 13;
int thedelay = 100;
// char keycode = 'x';
char pat[] = "x xx xxx xxxx xxxxx ";
int patlen = strlen(pat);
void setup()
{
}
void loop ()
{
int i = 0;
int i2 = 0;
while (i<patlen) {
i2 = i+5;
if (i2 >= patlen) i2 = i2 - patlen;
// maybe the % modulo operator could help!
if (pat[i] == 'x') tone(speakerPin, 400, 10);
delay(10);
if (pat[i2] == 'x') tone(speakerPin, 800, 10);
delay(thedelay);
i = i+1;
}
delay(thedelay*10);
}