Session 2: Programming
Dave Pelowitz
pelowitz@pelowitz.com
Tim Hamlin
tim.hamlin@gmail.com
Overview
 Roughly three months of 3 to 5 hours per week for all this material.
 Help people get the programming environment installed and working






on their system,
Load a simple program and run it (“blink” from the examples
provided), with some discussion of the code (line by line),
Discussion on what the arduino is, including input and output
capability,
Some discussion on what the C programming language is,
Write/load/run the simple edge trigger software enabling the minisumobot to run around on a competition field without going off the
edge,
Discuss what inputs/outputs are available for other sensors (opponent,
rear sensor, side sensors, etc.),
Overview next class/meeting.
Programming Environment
 www.arduino.cc/download
 UI to convert C to machine
 High level vs Machine
 Interpreted vs Compiled
 Elements of the UI
 Menu
 Icons
 Edit window
 Set Board and Port
 Uno
 Plug in USB to Uno and Computer
 Port (dependent on system)
Programming Environment (cont)
 ICONS
 Verify -- Checks your code for errors.
 Upload -- Compiles your code and uploads it to the
Arduino I/O board. See uploading below for details.
 New -- Creates a new sketch.
 Open -- Presents a menu of all the sketches in your
sketchbook. Clicking one will open it within the current
window.
 Save -- Saves your sketch.
 Serial Monitor -- Opens the serial monitor.
Simple Program
 Load blink into UI (file / examples / basics / blink)
 Compile and Upload into your arduino
Simple Program (cont.)
 Verify led is flashing
 Modify to print “on” and “off”
 Serial.begin(9600) in setup();
 Serial.println(“on”); after line with HIGH and
Serial.println(“off”); after line with LOW
 Leave off one of the “;”
 Compile without loading into Arduino
 Fix the error
 Compile and load into Arduino
 Open “Serial Monitor”
 Watch for “on” and “off” messages
The Arduino
 8 bit Micro-controller
 Arduino can sense the environment by receiving input from a
variety of sensors and can affect its surroundings by controlling
lights, motors, and other actuators. The microcontroller on the
board is programmed using the Arduino programming language
(based on Wiring) and the Arduino development environment
(based on Processing). Arduino projects can be stand-alone or
they can communicate with software running on a computer
(e.g. Flash, Processing, MaxMSP).
 ATmega328P, 32K bytes FLASH, 1K bytes EEPROM, 2K bytes
RAM.
 Sketches (programs) and Shields (physical add-on/plug-ins)
The Arduino Uno
http://arduino.cc/en/Main/
ArduinoBoardUno
Input and Outputs
Digital: 0-13
Analog: A0-A5 (10b gnd-5v)
Special Uses
0,1: Serial Communications
2,3: External Interrupts
3,5,6,9,10,11: PWM
A4,A5: I2C
10,11,12,13: SPI
13: LED
Used by Mini-SumoBot
3: buzzer
7: right motor direction
8: left motor direction
9: right motor PWM
10: left motor PWM
12: user push button
A1: optional battery level
4,5,11,A0,A2,A3:
Reflectance(edge sensor)
Arduino Shields
Ethernet, WIFI, Motor, WIFI, Touch Screen, GPS…
www.arduino.cc, www.adafruit.com, www.pololu.com, www.sparkfun.com, …
C Programming Language






“The C Programming Language”, Brian W. Kernighan, Dennis M. Ritchie
General Purpose programming language
Algebraic language: a=b+c, sqrt((a*a) + (b*b)), c=(5/9)(F-32)
Comments: /* this is a comment */ and //this is a comment
http://arduino.cc/en/Reference/HomePage
Variables





Symbolic Constants (manifest constants):




#define LOWER 0
#define UPPER 300
#define STEP 20
Arrays



What is a variable—a reference to a memory location (little endian).
Type: void, boolean, char, unsigned char, byte, int, unsigned int, word, long unsigned long, short, float,
double, string, String, array,
Scope: local, function, global, block {}
Form: case sensitive a != A, must start with a letter, no white space, no “special” characters. ALL variables
must be declared!
int a[100]
char[16]
Reference by value or by reference/de-reference

myInt
&myInt
*myInt
C Programming Language (cont)
 Expression: grammer
 Unary operators: * & - ! ~ prefix++ prefix-- postfix++ postfix--, (type
name)exp, sizeof exp, sizeof(type-name)
 Monadic and Dyadic
 Binary operators: * / % + - << >> < > <= >= == != & ^ | && ||
 Conditional: expressionA ? expressionB : expressionC
 Assignment: = += -= *= /= %= >>= <<= &= ^= |=
 Statements
 Form: “expression;” {}
 Assignment:



int myInt = 0;
myInt += 3;
myInt = myInt + 3;
 Precedence and Associativity (order of evaluation)

3*a/b
C Programming Language (cont)
 Precedence and Associativity (order of evaluation)
 3*a/b
 What if a is
near max int?
 Consider
3*(a/b)
Operator
Associativity
() [] -> .
Left to right
! ~ ++ -- - (type) * & sizeof
Right to left
*/%
Left to right
+-
Left to right
<< >>
Left to right
== !=
Left to right
&
Left to right
^
Left to right
|
Left to right
&&
Left to right
||
Left to right
?:
Left to right
= += -= etc.
Right to left
,
Left to right
C Programming Language (cont)
 Statements (cont)
 if (expression) statement;

if (myInt == 5) Serial.print(“myInt equals 5”);
 if (expression) statement else statement
 if (myInt != 5)
Serial.println(“myInt is not equal to five”);
else
Serial.println(“myInt is equal to five”);
 while (expression) statement
 while (j < 10) {Serial.println(j); ++j;}
 do statement while (expression);
 do j++; while (j < 10);
 do { Serial.println(j); ++j; } while (j < 10);
 do Serial.println(j++); while (j < 10);
 for (expressionAopt; expressionBopt; expressionCopt) statement;
 For (j=10,k=100; j>=0; j--){k++;Serial.print(j);Serial.print(“:”);Serial.println(k};
C Programming Language (cont)
 Statements (cont)
 switch (expression) statement and case constant-expression:
switch (i+k+k) {
case 0: Serial.println(“is zero”); break;
case 1:
case 2: Serial.println(“is either one or two”);break;
default: Serial.println(“no idea other than is not 0, 1, or 2”);
}
 continue; jumps to the end of while, do, or for loops
 goto identifier; identifier: (warning: leads to spaghetti code)
 return; or return expression;
C Programming Language (cont)
 Functions
 In classic c there will be a main()
 void setup()
 void loop()
 To create a function…

ret.type functionName(optional list of type var name )
int printMessage(int iRepeat, char* myMessage)
{
if (iRepeat < 1) return -1;
for (int i=0; i<iRepeat; i++)
Println(myMessage)
return 0;
}
 To call the function…

printMessage(10, “this is my message”);
C Programming Language (cont)
 Common errors…
 “if (a=b)...” instead of “if (a==b)…”.
 “a=b” or “myFunction(b)” without setting b to a value.
 myFunction(a) instead of (myFunction(&a) when the
function needs to change the value stored at a.
 Infinite loop—there are lots of forms. for (unsigned int uI=0;
uI==-1; uI++){…} or for(;;) or while(true){} or …
 Scope errors: e.g. variable with same name in and out of a
block: int i = 5; { int i = 6; println(i);} println(i);
 Missing { or } or both
 char szString[16]; then trying to put 16 chars into it and then
using it as a string. All “strings” terminate with zero byte.
 Where char szString[n] trying to index from 1 instead of 0
C Programming Language (cont)
 Good Practices…
 Comments


“header”
Inline
 Indentation
 Not needed for C but helps prevent errors and understand code
 Consistency
 {} placement of open (see next slide)
 Variable Names
 Hungarian notation (there are many other styles too)
 Scope_TypeName:
 g_uiTimeToComplete
global unsigned int
 m_fTimeToComplete
class member float
 szTimeToComplete
local array of character
Arduino Blink Example Revisited
/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.
This example code is in the public domain.
*/
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000);
// wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(1000);
// wait for a second
}
ZumoBot BorderDetect Software
 Load the Pololu Zumo Shield libraries
 https://github.com/pololu/zumo-shield or
http://www.pelowitz.com/zumo-shield-master.zip
 Download the archive from one of the sites above,
decompress it, and move each library folder (Pushbutton,
QTRSensors, ZumoBuzzer, ZumoExamples, ZumoMotors,
and ZumoReflectanceSensorArray) into the “libraries”
subdirectory inside your Arduino sketchbook directory. You
can view your sketchbook location by selecting
File→Preferences in the Arduino environment; if there is not
already a “libraries” folder in that location, you should create
it yourself.
 After installing the library, restart the Arduino environment
so it can find the Zumo Shield libraries and their examples.
ZumoBot BorderDetect Software
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
}
#include <ZumoBuzzer.h>
#include <ZumoMotors.h>
#include <Pushbutton.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#define LED 13
// this might need to be tuned for different lighting conditions, surfaces, etc.
#define QTR_THRESHOLD 1500 // microseconds
// these might need to be tuned for different motor types
#define REVERSE_SPEED 200 // 0 is stopped, 400 is full speed
#define TURN_SPEED
200
#define FORWARD_SPEED 200
#define REVERSE_DURATION 200 // ms
#define TURN_DURATION 400 // ms
ZumoBuzzer buzzer;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON); // pushbutton on pin 12
#define NUM_SENSORS 6
unsigned int sensor_values[NUM_SENSORS];
ZumoReflectanceSensorArray sensors(QTR_NO_EMITTER_PIN);
void waitForButtonAndCountDown()
{
digitalWrite(LED, HIGH);
button.waitForButton();
digitalWrite(LED, LOW);
// play audible countdown
for (int i = 0; i < 3; i++)
{
delay(1000);
buzzer.playNote(NOTE_G(3), 200, 15);
}
delay(1000);
buzzer.playNote(NOTE_G(4), 500, 15);
delay(1000);
}
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
}
void loop()
{
if (button.isPressed())
{
// if button is pressed, stop and wait for another press to go again
motors.setSpeeds(0, 0);
button.waitForRelease();
waitForButtonAndCountDown();
}
sensors.read(sensor_values);
if (sensor_values[0] < QTR_THRESHOLD)
{
// if leftmost sensor detects line, reverse and turn to the right
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(TURN_SPEED, -TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else if (sensor_values[5] < QTR_THRESHOLD)
{
// if rightmost sensor detects line, reverse and turn to the left
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(-TURN_SPEED, TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else
{
// otherwise, go straight
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
}
ZumoBot BorderDetect Software
#include <ZumoBuzzer.h>
#include <ZumoMotors.h>
#include <Pushbutton.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#define LED 13
// this might need to be tuned for different lighting conditions, surfaces, etc.
#define QTR_THRESHOLD 1500 // microseconds
#include <ZumoBuzzer.h>
#include <ZumoMotors.h>
#include <Pushbutton.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#define LED 13
// this might need to be tuned for different lighting conditions, surfaces, etc.
#define QTR_THRESHOLD 1500 // microseconds
// these might need to be tuned for different motor types
#define REVERSE_SPEED 200 // 0 is stopped, 400 is full speed
#define TURN_SPEED
200
#define FORWARD_SPEED 200
#define REVERSE_DURATION 200 // ms
#define TURN_DURATION 400 // ms
ZumoBuzzer buzzer;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON); // pushbutton on pin 12
#define NUM_SENSORS 6
unsigned int sensor_values[NUM_SENSORS];
ZumoReflectanceSensorArray sensors(QTR_NO_EMITTER_PIN);
void waitForButtonAndCountDown()
{
digitalWrite(LED, HIGH);
button.waitForButton();
digitalWrite(LED, LOW);
// play audible countdown
for (int i = 0; i < 3; i++)
{
delay(1000);
buzzer.playNote(NOTE_G(3), 200, 15);
}
delay(1000);
buzzer.playNote(NOTE_G(4), 500, 15);
delay(1000);
}
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
// these might need to be tuned for different motor types
#define REVERSE_SPEED 200 // 0 is stopped, 400 is full speed
#define TURN_SPEED
200
#define FORWARD_SPEED 200
#define REVERSE_DURATION 200 // ms
#define TURN_DURATION 400 // ms
ZumoBuzzer buzzer;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON); // pushbutton on pin 12
}
void loop()
{
if (button.isPressed())
{
// if button is pressed, stop and wait for another press to go again
motors.setSpeeds(0, 0);
button.waitForRelease();
waitForButtonAndCountDown();
}
sensors.read(sensor_values);
if (sensor_values[0] < QTR_THRESHOLD)
{
// if leftmost sensor detects line, reverse and turn to the right
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(TURN_SPEED, -TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else if (sensor_values[5] < QTR_THRESHOLD)
{
// if rightmost sensor detects line, reverse and turn to the left
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(-TURN_SPEED, TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else
{
// otherwise, go straight
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
}
ZumoBot BorderDetect Software
#define NUM_SENSORS 6
unsigned int sensor_values[NUM_SENSORS];
ZumoReflectanceSensorArray sensors(QTR_NO_EMITTER_PIN);
#include <ZumoBuzzer.h>
#include <ZumoMotors.h>
#include <Pushbutton.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#define LED 13
// this might need to be tuned for different lighting conditions, surfaces, etc.
#define QTR_THRESHOLD 1500 // microseconds
// these might need to be tuned for different motor types
#define REVERSE_SPEED 200 // 0 is stopped, 400 is full speed
#define TURN_SPEED
200
#define FORWARD_SPEED 200
#define REVERSE_DURATION 200 // ms
#define TURN_DURATION 400 // ms
ZumoBuzzer buzzer;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON); // pushbutton on pin 12
#define NUM_SENSORS 6
unsigned int sensor_values[NUM_SENSORS];
ZumoReflectanceSensorArray sensors(QTR_NO_EMITTER_PIN);
void waitForButtonAndCountDown()
{
digitalWrite(LED, HIGH);
button.waitForButton();
digitalWrite(LED, LOW);
void waitForButtonAndCountDown()
{
digitalWrite(LED, HIGH);
button.waitForButton();
digitalWrite(LED, LOW);
// play audible countdown
for (int i = 0; i < 3; i++)
{
delay(1000);
buzzer.playNote(NOTE_G(3), 200, 15);
}
delay(1000);
buzzer.playNote(NOTE_G(4), 500, 15);
delay(1000);
}
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
// play audible countdown
for (int i = 0; i < 3; i++)
{
delay(1000);
buzzer.playNote(NOTE_G(3), 200, 15);
}
delay(1000);
buzzer.playNote(NOTE_G(4), 500, 15);
delay(1000);
}
}
void loop()
{
if (button.isPressed())
{
// if button is pressed, stop and wait for another press to go again
motors.setSpeeds(0, 0);
button.waitForRelease();
waitForButtonAndCountDown();
}
sensors.read(sensor_values);
if (sensor_values[0] < QTR_THRESHOLD)
{
// if leftmost sensor detects line, reverse and turn to the right
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(TURN_SPEED, -TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else if (sensor_values[5] < QTR_THRESHOLD)
{
// if rightmost sensor detects line, reverse and turn to the left
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(-TURN_SPEED, TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else
{
// otherwise, go straight
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
}
ZumoBot BorderDetect Software
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
}
#include <ZumoBuzzer.h>
#include <ZumoMotors.h>
#include <Pushbutton.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#define LED 13
// this might need to be tuned for different lighting conditions, surfaces, etc.
#define QTR_THRESHOLD 1500 // microseconds
// these might need to be tuned for different motor types
#define REVERSE_SPEED 200 // 0 is stopped, 400 is full speed
#define TURN_SPEED
200
#define FORWARD_SPEED 200
#define REVERSE_DURATION 200 // ms
#define TURN_DURATION 400 // ms
ZumoBuzzer buzzer;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON); // pushbutton on pin 12
#define NUM_SENSORS 6
unsigned int sensor_values[NUM_SENSORS];
ZumoReflectanceSensorArray sensors(QTR_NO_EMITTER_PIN);
void waitForButtonAndCountDown()
{
digitalWrite(LED, HIGH);
button.waitForButton();
digitalWrite(LED, LOW);
// play audible countdown
for (int i = 0; i < 3; i++)
{
delay(1000);
buzzer.playNote(NOTE_G(3), 200, 15);
}
delay(1000);
buzzer.playNote(NOTE_G(4), 500, 15);
delay(1000);
}
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
}
void loop()
{
if (button.isPressed())
{
// if button is pressed, stop and wait for another press to go again
motors.setSpeeds(0, 0);
button.waitForRelease();
waitForButtonAndCountDown();
}
sensors.read(sensor_values);
if (sensor_values[0] < QTR_THRESHOLD)
{
// if leftmost sensor detects line, reverse and turn to the right
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(TURN_SPEED, -TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else if (sensor_values[5] < QTR_THRESHOLD)
{
// if rightmost sensor detects line, reverse and turn to the left
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(-TURN_SPEED, TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else
{
// otherwise, go straight
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
}
ZumoBot BorderDetect Software
void loop()
{
if (button.isPressed())
{
// if button is pressed, stop and wait for another press to go again
motors.setSpeeds(0, 0);
button.waitForRelease();
waitForButtonAndCountDown();
}
sensors.read(sensor_values);
#include <ZumoBuzzer.h>
#include <ZumoMotors.h>
#include <Pushbutton.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#define LED 13
// this might need to be tuned for different lighting conditions, surfaces, etc.
#define QTR_THRESHOLD 1500 // microseconds
// these might need to be tuned for different motor types
#define REVERSE_SPEED 200 // 0 is stopped, 400 is full speed
#define TURN_SPEED
200
#define FORWARD_SPEED 200
#define REVERSE_DURATION 200 // ms
#define TURN_DURATION 400 // ms
ZumoBuzzer buzzer;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON); // pushbutton on pin 12
#define NUM_SENSORS 6
unsigned int sensor_values[NUM_SENSORS];
ZumoReflectanceSensorArray sensors(QTR_NO_EMITTER_PIN);
void waitForButtonAndCountDown()
{
digitalWrite(LED, HIGH);
button.waitForButton();
digitalWrite(LED, LOW);
// play audible countdown
for (int i = 0; i < 3; i++)
{
delay(1000);
buzzer.playNote(NOTE_G(3), 200, 15);
}
delay(1000);
buzzer.playNote(NOTE_G(4), 500, 15);
delay(1000);
}
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
}
if (sensor_values[0] < QTR_THRESHOLD)
{
// if leftmost sensor detects line, reverse and turn to the right
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(TURN_SPEED, -TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else if (sensor_values[5] < QTR_THRESHOLD)
{
void loop()
{
if (button.isPressed())
{
// if button is pressed, stop and wait for another press to go again
motors.setSpeeds(0, 0);
button.waitForRelease();
waitForButtonAndCountDown();
}
sensors.read(sensor_values);
if (sensor_values[0] < QTR_THRESHOLD)
{
// if leftmost sensor detects line, reverse and turn to the right
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(TURN_SPEED, -TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else if (sensor_values[5] < QTR_THRESHOLD)
{
// if rightmost sensor detects line, reverse and turn to the left
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(-TURN_SPEED, TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else
{
// otherwise, go straight
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
}
ZumoBot BorderDetect Software
else if (sensor_values[5] < QTR_THRESHOLD)
{
// if rightmost sensor detects line, reverse and turn to the left
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(-TURN_SPEED, TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else
{
// otherwise, go straight
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
}
#include <ZumoBuzzer.h>
#include <ZumoMotors.h>
#include <Pushbutton.h>
#include <QTRSensors.h>
#include <ZumoReflectanceSensorArray.h>
#define LED 13
// this might need to be tuned for different lighting conditions, surfaces, etc.
#define QTR_THRESHOLD 1500 // microseconds
// these might need to be tuned for different motor types
#define REVERSE_SPEED 200 // 0 is stopped, 400 is full speed
#define TURN_SPEED
200
#define FORWARD_SPEED 200
#define REVERSE_DURATION 200 // ms
#define TURN_DURATION 400 // ms
ZumoBuzzer buzzer;
ZumoMotors motors;
Pushbutton button(ZUMO_BUTTON); // pushbutton on pin 12
#define NUM_SENSORS 6
unsigned int sensor_values[NUM_SENSORS];
ZumoReflectanceSensorArray sensors(QTR_NO_EMITTER_PIN);
void waitForButtonAndCountDown()
{
digitalWrite(LED, HIGH);
button.waitForButton();
digitalWrite(LED, LOW);
// play audible countdown
for (int i = 0; i < 3; i++)
{
delay(1000);
buzzer.playNote(NOTE_G(3), 200, 15);
}
delay(1000);
buzzer.playNote(NOTE_G(4), 500, 15);
delay(1000);
}
void setup()
{
// uncomment if necessary to correct motor directions
//motors.flipLeftMotor(true);
//motors.flipRightMotor(true);
pinMode(LED, HIGH);
waitForButtonAndCountDown();
}
void loop()
{
if (button.isPressed())
{
// if button is pressed, stop and wait for another press to go again
motors.setSpeeds(0, 0);
button.waitForRelease();
waitForButtonAndCountDown();
}
sensors.read(sensor_values);
if (sensor_values[0] < QTR_THRESHOLD)
{
// if leftmost sensor detects line, reverse and turn to the right
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(TURN_SPEED, -TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else if (sensor_values[5] < QTR_THRESHOLD)
{
// if rightmost sensor detects line, reverse and turn to the left
motors.setSpeeds(-REVERSE_SPEED, -REVERSE_SPEED);
delay(200);
motors.setSpeeds(-TURN_SPEED, TURN_SPEED);
delay(300);
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
else
{
// otherwise, go straight
motors.setSpeeds(FORWARD_SPEED, FORWARD_SPEED);
}
}
Next Session
 Mechanically adding sensors and other stuff
 Side
 Rear
 Modifying the program for the new sensors
 Available arduino inputs
 Where in the code
 Optimizing the code
 Float vs Int, * vs /, use of arrays[], use of delay()
 Implementing priorities by how you organize the code
 Using the runtime clock instead of delay() function
 New strategies for a winning bot.
 The sky’s the limit within 500 grams and 10 x 10 cm.