Intro Arduino

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NeoPixel by Adafruit
NeoPixel Überguide Installing Arduino Library

Arduino Basics

1. Programs are called sketches and have a file extension of .ino. They must be in a folder named the same as the file.

2. There are two functions in a sketch:
setup() – This function is called when a sketch starts. Use it to initialize pin modes, serial communications, start using libraries, etc.

loop() – After creating a setup() function, which initializes and sets the initial values, the loop() function loops forever. Use this for the main loop of your sketch (program).

3. Once a program/sketch has been uploaded to an Arduino, it stays on it until a new one is loaded. The board can be powered by a battery after the sketch is loaded.

4. Using the Arduino
   - Under Tools menu, check that Board is set to “Arduino/Genuino Uno” or "Arduino/Genuino Mega or Mega 2560" for the larger board.
   - Under Tools menu, the Port usually needs to be set to the highest numbered COM Port
   - Under Help menu, select Reference to see all the commands
   - Under File menu, look at some the Examples

5. Pseudo Random Numbers
   Seed random # generator in setup:    randomSeed(analogRead(0));
   Generate a random # between 0 and 9: random(10);

6. Serial Monitor
This allows you to send data from your board back to your computer. Click on the Serial Monitor icon on the right side of the toolbar.
Initialize serial monitor in setup(): Serial.begin(9600);

Output text:                  Serial.println("Hello World!");
Output numbers/variables:       Serial.println(A);

Sample NeoPixel Ring Code

#include <Adafruit_NeoPixel.h>

int NumPixels = 16; // set this to number of pixels on your ring
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NumPixels, 7); // NumPixels, Pin#

// setup() runs once at the beginning
void setup()
{
   pixels.begin(); // Initialize the NeoPixels

   for (int n=0; n<NumPixels; n++)   // reset board to all pixels off
{
      pixels.setPixelColor(n, pixels.Color(0,0,0));
}
pixels.show();
}

// loop() repeats forever
void loop()
{
   for (int n=0; n<NumPixels; n++)   // set all pixels to red one at a time
{
      pixels.setPixelColor(n, pixels.Color(40,0,0));
      pixels.show();
      delay(250);    // delay a quarter second
}
}

Sample Line Following Robot Code

#include <QTRSensors.h>

// Arduino Mega - connect QTR wires to Analog pins 0 - 7
QTRSensorsRC qtr((char[]) {54, 55, 56, 57, 58, 59, 60, 61}, 8); // Mega code

// Arduino Uno - connect QTR wires to Analog pins 0 - 5
// QTRSensorsRC qtr((char[]) {14, 15, 16, 17, 18, 19}, 6); // Uno code

unsigned int sensor[8];

// connect motor controller pins to Arduino digital pins
int enA = 2; int in1 = 3; int in2 = 4;   // motor 1
int in3 = 5; int in4 = 6; int enB = 7;   // motor 2

void Stop()
{
   digitalWrite(in1, LOW);
   digitalWrite(in2, LOW);
   digitalWrite(in3, LOW);
   digitalWrite(in4, LOW);
}

void Forward (int LeftSpeed, int RightSpeed) // range 0 - 255
{
   digitalWrite(in1, HIGH); // turn on left motor to forward
   digitalWrite(in2, LOW);
   analogWrite(enA, LeftSpeed);
   digitalWrite(in3, HIGH); // turn on right motor to forward
   digitalWrite(in4, LOW);
   analogWrite(enB, RightSpeed);
}

void Reverse (int LeftSpeed, int RightSpeed) // range 0-255
{
   digitalWrite(in1, LOW); // turn on left motor to forward
   digitalWrite(in2, HIGH);
   analogWrite(enA, LeftSpeed);
   digitalWrite(in3, LOW); // turn on right motor to forward
   digitalWrite(in4, HIGH);
   analogWrite(enB, RightSpeed);
}

void setup()
{
   // set all the motor control pins to outputs
   pinMode(enA, OUTPUT);
   pinMode(enB, OUTPUT);
   pinMode(in1, OUTPUT);
   pinMode(in2, OUTPUT);
   pinMode(in3, OUTPUT);
   pinMode(in4, OUTPUT);

   Serial.begin(9600); // used to write to serial monitor

   // pushbutton
   pinMode(53,INPUT_PULLUP);

   while (digitalRead(53) != LOW) // wait for pushbutton to start motors
   {
      //for testing print out sensor value to Serial Monitor
      //qtr.read(sensor);
      //Serial.print(sensor[0]); Serial.print(" "); Serial.print(sensor[1]); Serial.print(" ");
      //Serial.print(sensor[2]); Serial.print(" "); Serial.print(sensor[3]); Serial.print(" ");
      //Serial.print(sensor[4]); Serial.print(" "); Serial.print(sensor[5]); Serial.print(" ");
      //Serial.print(sensor[6]); Serial.print(" "); Serial.print(sensor[7]); Serial.print("\n");
      //delay(500);
   }
   Forward(100,100);
}

void loop()
{
   qtr.read(sensor);

   if (sensor[0]<700)
   {
      Forward(40,200);
   }
   else if (sensor[1]<700)
   {
      Forward(80,200);
   }
   else if (sensor[2]<700)
   {
      Forward(100,200);
   }
   else if (sensor[5]<700)
   {
      Forward(200,100);
   }
   else if (sensor[6]<700)
   {
      Forward(200,80);
   }
   else if (sensor[7]<700)
   {
      Forward(200,40);
   }
   else if (sensor[3] < 700 || sensor[4] < 700)
   {
      Forward(255,255);
   }
   else
      Forward(150,150);
   delay(30);
}