Exercise 1: Make a Processing Etch A Sketch
In this recitation, we finally started to combine what we learned about Arduino and Processing together to make two small projects! Overall, there were two challenges I faced. First, sometimes I forgot how to connect the circuit since we did not practice for a really long time. Second, how to combine the code from Arduino and Processing together. Thanks to the sample code, it saved a lot of work for me to make it run.
I built a circuit with two potentiometers, which were separated connected to pin A0 and A1. With the help of Katie, I corrected some of my mistakes in code. Nevertheless, the track of the ellipse was not so stable that I expected. I tried to switch the direction, it became a little better.
Sketch:
Video:
Code:
void setup() {
Serial.begin(9600);
}
void loop() {
int sensor1 = analogRead(A0);
int sensor2 = analogRead(A1);
// keep this format
Serial.print(sensor1);
Serial.print(“,”); // put comma between sensor values
Serial.print(sensor2);
Serial.println();
delay(100);
}
import processing.serial.*;
String myString = null;
Serial myPort;
int NUM_OF_VALUES = 2; /** YOU MUST CHANGE THIS ACCORDING TO YOUR PROJECT **/
int[] sensorValues; /** this array stores values from Arduino **/
float x;
float y;
void setup() {
size(500, 500);
background(0);
setupSerial();
}
void draw() {
updateSerial();
printArray(sensorValues);
x = map(sensorValues[0], 0, 1023, 0, width);
y = map(sensorValues[1], 0, 1023, 0, height);
noStroke();
ellipse(x, y, 10, 10);
// use the values like this!
// sensorValues[0]
// add your code
//
}
void setupSerial() {
printArray(Serial.list());
myPort = new Serial(this, Serial.list()[4], 9600);
myPort.clear();
// Throw out the first reading,
// in case we started reading in the middle of a string from the sender.
myString = myPort.readStringUntil( 10 ); // 10 = ‘\n’ Linefeed in ASCII
myString = null;
sensorValues = new int[NUM_OF_VALUES];
}
void updateSerial() {
while (myPort.available() > 0) {
myString = myPort.readStringUntil( 10 ); // 10 = ‘\n’ Linefeed in ASCII
if (myString != null) {
String[] serialInArray = split(trim(myString), “,”);
if (serialInArray.length == NUM_OF_VALUES) {
for (int i=0; i<serialInArray.length; i++) {
sensorValues[i] = int(serialInArray[i]);
}
}
}
}
}
Exercise 2: Make a musical instrument with Arduino
In this exercise, first I built a circuit with a buzzer connecting to pin 9 and the ground. I also designed to use the mouse to control the sound of the buzzer. Thus, the frequency and duration should reflect the position of mouseX and mouseY. So when I moved the “paw” on my screen, the sound of the buzzer also changed.
Moreover, Eric also reminded me that it is not possible to generate tones lower than 31Hz. So I had to map the frequency to make sure that it sounds right.
Sketch:
Video:
Code:
#define NUM_OF_VALUES 2 /** YOU MUST CHANGE THIS ACCORDING TO YOUR PROJECT **/
/** DO NOT REMOVE THESE **/
int tempValue = 0;
int valueIndex = 0;
/* This is the array of values storing the data from Processing. */
int values[NUM_OF_VALUES];
void setup() {
Serial.begin(9600);
pinMode(13, OUTPUT);
pinMode(9, OUTPUT);
}
void loop() {
getSerialData();
int freq = map(values[0], 0, 500, 31, 500000);
tone(9, freq, values[1]);
}
//recieve serial data from Processing
void getSerialData() {
if (Serial.available()) {
char c = Serial.read();
//switch – case checks the value of the variable in the switch function
//in this case, the char c, then runs one of the cases that fit the value of the variable
//for more information, visit the reference page: https://www.arduino.cc/en/Reference/SwitchCase
switch (c) {
//if the char c from Processing is a number between 0 and 9
case ‘0’…’9′:
//save the value of char c to tempValue
//but simultaneously rearrange the existing values saved in tempValue
//for the digits received through char c to remain coherent
//if this does not make sense and would like to know more, send an email to me!
tempValue = tempValue * 10 + c – ‘0’;
break;
//if the char c from Processing is a comma
//indicating that the following values of char c is for the next element in the values array
case ‘,’:
values[valueIndex] = tempValue;
//reset tempValue value
tempValue = 0;
//increment valuesIndex by 1
valueIndex++;
break;
//if the char c from Processing is character ‘n’
//which signals that it is the end of data
case ‘n’:
//save the tempValue
//this will b the last element in the values array
values[valueIndex] = tempValue;
//reset tempValue and valueIndex values
//to clear out the values array for the next round of readings from Processing
tempValue = 0;
valueIndex = 0;
break;
//if the char c from Processing is character ‘e’
//it is signalling for the Arduino to send Processing the elements saved in the values array
//this case is triggered and processed by the echoSerialData function in the Processing sketch
case ‘e’: // to echo
for (int i = 0; i < NUM_OF_VALUES; i++) {
Serial.print(values[i]);
if (i < NUM_OF_VALUES – 1) {
Serial.print(‘,’);
}
else {
Serial.println();
}
}
break;
}
}
}
import processing.serial.*;
int NUM_OF_VALUES = 2; /** YOU MUST CHANGE THIS ACCORDING TO YOUR PROJECT **/
Serial myPort;
String myString;
// This is the array of values you might want to send to Arduino.
int values[] = new int[NUM_OF_VALUES];
void setup() {
size(500, 500);
background(0);
printArray(Serial.list());
myPort = new Serial(this, Serial.list()[ 4 ], 9600);
myPort.clear();
// Throw out the first reading,
// in case we started reading in the middle of a string from the sender.
myString = myPort.readStringUntil( 10 ); // 10 = ‘\n’ Linefeed in ASCII
myString = null;
}
void draw() {
background(255);
paw(mouseX, mouseY);
// changes the values
for (int i=0; i<values.length; i++) {
values[0] = mouseX; /** Feel free to change this!! **/
values[1] = mouseY;
}
// sends the values to Arduino.
sendSerialData();
echoSerialData(200);
}
void paw(float x, float y) {
pushMatrix();
translate(x, y);
noStroke();
fill(30,100);
ellipse(70, 90, 80, 55);
ellipse(25, 60, 20, 30);
ellipse(55, 40, 20, 30);
ellipse(85, 40, 20, 30);
ellipse(115, 60, 20, 30);
popMatrix();
}
void sendSerialData() {
String data = “”;
for (int i=0; i<values.length; i++) {
data += values[i];
//if i is less than the index number of the last element in the values array
if (i < values.length-1) {
data += “,”; // add splitter character “,” between each values element
}
//if it is the last element in the values array
else {
data += “n”; // add the end of data character “n”
}
}
//write to Arduino
myPort.write(data);
}
void echoSerialData(int frequency) {
//write character ‘e’ at the given frequency
//to request Arduino to send back the values array
if (frameCount % frequency == 0) myPort.write(‘e’);
String incomingBytes = “”;
while (myPort.available() > 0) {
//add on all the characters received from the Arduino to the incomingBytes string
incomingBytes += char(myPort.read());
}
//print what Arduino sent back to Processing
print( incomingBytes );
}
