Remove everything from the breadboard and let’s make CIRCUIT #1
Copy the code from the manual.
Now make it blink faster!
Blinking 2 LEDs
int L1 = 13; // LED connected to digital pin 13
int L2 = 12; // LED connected to digital pin 12
// The setup() method runs once, when the sketch starts
void setup() {
// initialize the digital pin as an output:
pinMode(L1, OUTPUT);
pinMode(L2, OUTPUT);
}
// the loop() method runs over and over again,
// as long as the Arduino has power
void loop()
{
digitalWrite(L1, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(L2, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(L1, LOW); // set the LED off
delay(1000); // wait for a second
digitalWrite(L2, LOW); // set the LED off
delay(1000);
}
Make them blink at the same time and alternated.
Blinking 3 LEDs
Now 3 LEDs!
int L1 = 13; // LED connected to digital pin 13
int L2 = 12; // LED connected to digital pin 12
int L3 = 11; // LED connected to digital pin 11
// The setup() method runs once, when the sketch starts
void setup() {
// initialize the digital pin as an output:
pinMode(L1, OUTPUT);
pinMode(L2, OUTPUT);
pinMode(L3, OUTPUT);
}
// the loop() method runs over and over again,
// as long as the Arduino has power
void loop()
{
digitalWrite(L1, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(L2, HIGH); // set the LED on
delay(1000); // wait for a second
digitalWrite(L3, HIGH); // set the LED off
delay(1000); // wait for a second
digitalWrite(L1, LOW); // set the LED off
digitalWrite(L2, LOW); // set the LED off
digitalWrite(L3, LOW); // set the LED off
delay(1000);
}
Exercise 1.
Using all of your red LEDs, make a circuit that reproduces KITT’s flashing light pattern from Knight Rider.
Upload a video of your working circuit on YouTube and post the link on the blog. Include your Arduino code.
To upload code into the blog, we are using the WP-Syntax WordPress plugin. To embed code in your post, switch to the “HTML” view tab in the WordPress editor, and then wrap your code with the following tags:
Exercise 2
Get working “Circuit #3” (RGB LED) from the SIK GUIDE book. The code for this sketch is available at http://www.sparkfun.com/sikcode
/*
SparkFun Inventor's Kit
Example sketch 03
RGB LED
Make an RGB LED display a rainbow of colors!
Hardware connections:
An RGB LED is actually three LEDs (red, green, and blue) in
one package. When you run them at different brightnesses,
the red, green and blue mix to form new colors.
Starting at the flattened edge of the flange on the LED,
the pins are ordered RED, COMMON, GREEN, BLUE.
Connect RED to a 330 Ohm resistor. Connect the other end
of the resistor to Arduino digital pin 9.
Connect COMMON pin to GND.
Connect GREEN to a 330 Ohm resistor. Connect the other end
of the resistor to Arduino digital pin 10.
Connect BLUE to a 330 Ohm resistor. Connect the other end
of the resistor to Arduino digital pin 11.
This sketch was written by SparkFun Electronics,
with lots of help from the Arduino community.
Visit http://learn.sparkfun.com/products/2 for SIK information.
Visit http://www.arduino.cc to learn about the Arduino.
Version 2.0 6/2012 MDG
*/
// First we'll define the pins by name to make the sketch
// easier to follow.
// Here's a new trick: putting the word "const" in front of a
// variable indicates that this is a "constant" value that will
// never change. (You don't have to do this, but if you do, the
// Arduino will give you a friendly warning if you accidentally
// try to change the value, so it's considered good form.)
const int RED_PIN = 9;
const int GREEN_PIN = 10;
const int BLUE_PIN = 11;
// This variable controls how fast we loop through the colors.
// (Try changing this to make the fading faster or slower.)
int DISPLAY_TIME = 100; // In milliseconds
void setup()
{
// Here we'll configure the Arduino pins we're using to
// drive the LED to be outputs:
pinMode(RED_PIN, OUTPUT);
pinMode(GREEN_PIN, OUTPUT);
pinMode(BLUE_PIN, OUTPUT);
}
void loop()
{
// In this sketch, we'll start writing our own functions.
// This makes the sketch easier to follow by dividing up
// the sketch into sections, and not having everything in
// setup() or loop().
// We'll show you two ways to run the RGB LED.
// The first way is to turn the individual LEDs (red, blue,
// and green) on and off in various combinations. This gives you
// a total of eight colors (if you count "black" as a color).
// We've written a function called mainColors() that steps
// through all eight of these colors. We're only "calling" the
// function here (telling it to run). The actual function code
// is further down in the sketch.
mainColors();
// The above function turns the individual LEDs full-on and
// full-off. If you want to generate more than eight colors,
// you can do so by varying the brightness of the individual
// LEDs between full-on and full-off.
// The analogWrite() function lets us do this. This function
// lets you dim a LED from full-off to full-on over 255 steps.
// We've written a function called showSpectrum() that smoothly
// steps through all the colors. Again we're just calling it
// here; the actual code is further down in this sketch.
showSpectrum();
}
// Here's the mainColors() function we've written.
// This function displays the eight "main" colors that the RGB LED
// can produce. If you'd like to use one of these colors in your
// own sketch, you cancopy and paste that section into your code.
void mainColors()
{
// Off (all LEDs off):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Red (turn just the red LED on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Green (turn just the green LED on):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Blue (turn just the blue LED on):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
// Yellow (turn red and green on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, LOW);
delay(1000);
// Cyan (turn green and blue on):
digitalWrite(RED_PIN, LOW);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
// Purple (turn red and blue on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, LOW);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
// White (turn all the LEDs on):
digitalWrite(RED_PIN, HIGH);
digitalWrite(GREEN_PIN, HIGH);
digitalWrite(BLUE_PIN, HIGH);
delay(1000);
}
// Below are two more functions we've written,
// showSpectrum() and showRGB().
// showRGB() displays a single color on the RGB LED.
// You call showRGB() with the number of a color you want
// to display.
// showSpectrum() steps through all the colors of the RGB LED,
// displaying a rainbow. showSpectrum() actually calls showRGB()
// over and over to do this.
// We'll often break tasks down into individual functions like
// this, which makes your sketches easier to follow, and once
// you have a handy function, you can reuse it in your other
// programs.
// showSpectrum()
// This function steps through all the colors of the RGB LED.
// It does this by stepping a variable from 0 to 768 (the total
// number of colors), and repeatedly calling showRGB() to display
// the individual colors.
// In this function, we're using a "for() loop" to step a variable
// from one value to another, and perform a set of instructions
// for each step. For() loops are a very handy way to get numbers
// to count up or down.
// Every for() loop has three statements separated by semicolons:
// 1. Something to do before starting
// 2. A test to perform; as long as it's true,
// it will keep looping
// 3. Something to do after each loop (usually
// increase a variable)
// For the for() loop below, these are the three statements:
// 1. x = 0; Before starting, make x = 0.
// 2. x < 768; While x is less than 768, run the
// following code.
// 3. x++ Putting "++" after a variable means
// "add one to it". (You can also use "x = x + 1")
// Every time you go through the loop, the statements following
// the loop (those within the brackets) will run.
// And when the test in statement 2 is finally false, the sketch
// will continue.
void showSpectrum()
{
int x; // define an integer variable called "x"
// Now we'll use a for() loop to make x count from 0 to 767
// (Note that there's no semicolon after this line!
// That's because the for() loop will repeat the next
// "statement", which in this case is everything within
// the following brackets {} )
for (x = 0; x < 768; x++)
// Each time we loop (with a new value of x), do the following:
{
showRGB(x); // Call RGBspectrum() with our new x
delay(10); // Delay for 10 ms (1/100th of a second)
}
}
// showRGB()
// This function translates a number between 0 and 767 into a
// specific color on the RGB LED. If you have this number count
// through the whole range (0 to 767), the LED will smoothly
// change color through the entire spectrum.
// The "base" numbers are:
// 0 = pure red
// 255 = pure green
// 511 = pure blue
// 767 = pure red (again)
// Numbers between the above colors will create blends. For
// example, 640 is midway between 512 (pure blue) and 767
// (pure red). It will give you a 50/50 mix of blue and red,
// resulting in purple.
// If you count up from 0 to 767 and pass that number to this
// function, the LED will smoothly fade between all the colors.
// (Because it starts and ends on pure red, you can start over
// at 0 without any break in the spectrum).
void showRGB(int color)
{
int redIntensity;
int greenIntensity;
int blueIntensity;
// Here we'll use an "if / else" statement to determine which
// of the three (R,G,B) zones x falls into. Each of these zones
// spans 255 because analogWrite() wants a number from 0 to 255.
// In each of these zones, we'll calculate the brightness
// for each of the red, green, and blue LEDs within the RGB LED.
if (color = 512 // zone 3
{
redIntensity = (color - 512); // red off to on
greenIntensity = 0; // green is always off
blueIntensity = 255 - (color - 512); // blue on to off
}
// Now that the brightness values have been set, command the LED
// to those values
analogWrite(RED_PIN, redIntensity);
analogWrite(BLUE_PIN, blueIntensity);
analogWrite(GREEN_PIN, greenIntensity);
}
Code to slowly fade from one random color to another:
// This program blends smoothly (linearly)
// from one random color, to another,
// over the course of a period of 1000 milliseconds
const int RED_PIN = 9;
const int GREEN_PIN = 10;
const int BLUE_PIN = 11;
int rp,gp,bp; // the P (previous) color
int rn,gn,bn; // the N (next) color
int prevChangeTime;
int period = 1000;
//---------------------------------------------
void setup() {
pinMode (RED_PIN, OUTPUT);
pinMode (GREEN_PIN, OUTPUT);
pinMode (BLUE_PIN, OUTPUT);
prevChangeTime = 0;
int rp = random (0,255);
int gp = random (0,255);
int bp = random (0,255);
int rn = random (0,255);
int gn = random (0,255);
int bn = random (0,255);
}
//---------------------------------------------
void loop() {
int curTime = millis();
int elapsed = curTime - prevChangeTime;
if (elapsed > period){
prevChangeTime = curTime;
rp = rn;
gp = gn;
bp = bn;
rn = random (0,255);
gn = random (0,255);
bn = random (0,255);
}
int rc = map (elapsed, 0, period, rp, rn);
int gc = map (elapsed, 0, period, gp, gn);
int bc = map (elapsed, 0, period, bp, bn);
analogWrite (RED_PIN, rc);
analogWrite (GREEN_PIN, gc);
analogWrite (BLUE_PIN, bc);
}
Your Arduino kits have been designed and provided by Ben Peoples of BirdBrain Labs, Pittsburgh’s very own travelling Arduino salesman. The kits consist of a Sparkfun Inventor’s Kit base, along with a small handful of extra goodies. The total cost will be just about exactly $100:
// Circular motion
void setup() {
size(300, 300);
}
void draw() {
smooth();
// comment or uncomment background to leave trails.
//background(127);
float centerX = 150;
float centerY = 150;
float amplitude = 50.0;
float period = 0.003;
// Circular motion linked to the (time-varying) millis() function.
// Note that millis() gets large fast (1000 per second!),
// so we have to multiply it by a small number to work well.
float xPos = centerX + amplitude * sin(millis()*period);
float yPos = centerY + amplitude * cos(millis()*period);
ellipse(xPos, yPos, 20, 20);
}
// Zeno's interpolated motion
float xPos;
float yPos;
void setup(){
size(300,300);
xPos = width/2;
yPos = height/2;
}
void draw(){
// on each frame, move 5% towards the target (mouse) in X,
// and move 2% towards the target (mouse) in Y
xPos = 0.95*xPos + 0.05*mouseX;
yPos = 0.98*yPos + 0.02*mouseY;
ellipse(xPos, yPos, 20,20);
}
Drunk Walk:
// Drunk walk! A random offset on each frame.
// It creates a feedback, using the global variables xPos and yPos:
// Their current values are related to their previous values.
float xPos;
float yPos;
void setup(){
size(300,300);
xPos = width/2;
yPos = height/2;
}
void draw(){
background(127);
// my current position is a small random offset from my previous position.
xPos = xPos + random(-3,3);
yPos = yPos + random(-3,3);
ellipse(xPos, yPos, 20,20);
}
Variables, Iteration, Blocks A reminder of the basics.
Recap of variables (The multiple-lines example)
for loops (The multiple-lines example, generalized)
Side note: Variables are scoped with respect to { } blocks.
Diagnosing your code How can you inspect the value which some variable holds?
Printing the values of variables to the console
Constructing simple strings through concatenation.
Displaying strings by drawing text() to the canvas
Discussion topics for Monday 9/24:
Basic mathematics and order of operations;
Variables: integers vs. floats
integer vs. float mathematics
brief mention of char, byte, String, boolean variables
random()
New Topics for Wednesday 9/26:
Towards greater sophistication.
translate(), scale(), rotate()
map(), constrain()
Mouse Interaction Interactions based on continuous cursor data.
Printing out the mouse values
A ball linked to the mouse directly
A ball mathematically related to the mouse value
A ball linked to the mouse by inverse relationships
A ball linked to the mouse by an intermediate variable
Conditional Testing and Interaction The if{} structure, with discrete and continuous mouse data.
Introduction to conditional testing. if (mouseX > val)
Interactions based on discrete mouse data: if (mousePressed)
The mousePressed() method
A latch, which calls draw() only after mousePressed().
Readings:
Getting Started with Processing: Chapter 4 (pp. 37-50)
Processing: A Handbook, the following sections:
Data 1: Variables;
Math 1: Arithmetic;
Control 2: Repetition;
Data 2: Text;
Math 4: Random;
Transform 1: Translate, Matrices
Transform 2: Rotate, Scale
For Loop Example
In this example, a for{} loop is used to govern the (A) vertical position and (B) stroke color, of a set of horizontal lines.
// For Loop Example
size (300, 300);
background (255, 200, 200);
strokeWeight (3);
stroke(0, 0, 0);
fill (155, 255, 255);
smooth();
float leftEdge = 30;
float rightEdge = 200;
float mySpacing = 20;
int nLines = 14;
for (int i=1; i <= nLines; i=i+1) {
float greyVal = map(i, 1, nLines, 0, 255);
stroke (greyVal);
float yPosition = i*mySpacing;
line (leftEdge, yPosition, rightEdge, yPosition);
ellipse (rightEdge, yPosition, 13, 13);
}
For Loop With Random Numbers
In this example, a for{} loop is used to control the (A) fill color and (B) horizontal position of a set of circles. What happens if the line which declares and assigns the float variable “ry” is pulled outside of the for{} loop?
// For Loop With Random Numbers
size (300, 300);
background (255, 200, 200);
strokeWeight (2);
smooth ();
line (0,150, width,150);
for (int i=0; i < 10; i++) {
float rx = i*30 + 15;
float ry = random(140, 160); // Y positions are randomized within 140..160
float rGray = random(0, 255); // Gray values are randomized within 0...255
fill (rGray);
ellipse (rx, ry, 20, 20) ;
}
Live interaction with iteration (for loop):
This code demonstrates how a for{} loop can be used to draw a structure which responds in real-time to interactive input.
// Live interaction with iteration (for loop)
void setup() {
size (400, 300);
}
void draw() {
background(255, 200, 200);
strokeWeight(3);
smooth( );
for (int i=1; i<20; i++) {
if (i == 8) { // Equality test. Note the "double-equals" ( == ) !!!!
stroke(255, 0, 0);
line (width/2, 0, mouseX, mouseY);
}
else {
stroke (0, 0, 0);
ellipse(i*20, mouseY-50, 25, 25);
}
}
}
Embedded Iteration
This is the classic “nested for{} loop”, in which one loop (controlling vertical position and green-ness) is nested inside an outer loop (which controls horizontal position and redness).
