>> ARDUINO - MY FIRST CUSTOM HACK

After tinkering around with the arduino starter kit; I simply had to extend some of the examples and mix and match them to create something unique just for fun. In this case, I took one example using six LEDs and another using the piezo element to create an audibly annoying but visually satisfying hack.

Once you have played with all the samples in the arduino starter kit it should be obvious what changes I made - simply connect six red LED and the piezo elements to the digital connections of the arduino uno. The LEDs are then connected to the ground lines using 220Ω resistors - should be simple figure out based on the other examples provided.

The sketch code is below:

• //
  // simple arduino sketch using six LED's and the piezo element 
  //
  // - design is to have a sequence 0,1,2,3,4,5,5,4,3,2,1,0 repeat
  // - NOTE: double use of LEDs 0 and 5 - this is for nice visual effect
  
  #define ledPINBase    2
  #define ledPINCount   6  // pins 2,3,4,5,6 and 7
  #define piezoPIN      8
  
  // we want to move across the LED pins in approximately a second
  #define delayPeriod   (1000 / ledPINCount)
  
  // we want to play tones an octive up and down from middle C
  #define toneBase      262
  #define toneDiff      ((toneBase * 2) / ledPINCount)
  #define toneDuration  (delayPeriod / 2)
  
  // some global variables
  int g_direction = 1;
  int g_led       = ledPINBase;
  
  // configuration of the arduino 
  void setup()
  {
    // configure the LED pins - turn them all off
    for (int i=ledPINBase; i<(ledPINBase+ledPINCount); i++)
    {
      pinMode(i, OUTPUT);
      digitalWrite(i, LOW);
    }
  }
  
  // called periodically by the arduino core - this is where we do stuff
  void loop()
  {
    int state;
  
    // for visual effect; toggle the state of the LED
    state = digitalRead(g_led);
    if (state == HIGH) digitalWrite(g_led, LOW);
    else               digitalWrite(g_led, HIGH);
      
    // iterate forwards through LEDs
    if (g_direction == 1)
    {
      g_led++;
  
      // have we had a led counter overflow?
      if (g_led == (ledPINBase+ledPINCount)) 
      {
        g_led == (ledPINBase+ledPINCount)-1;
        g_direction = -1;
      }
    }
  
    // iterate backwards through LEDs
    else
    {
      g_led--;
        
      // have we had a led counter underflow
      if (g_led == (ledPINBase-1)) 
      {
        g_led = ledPINBase;
        g_direction = 1;
      }
    }
      
    // play a ticking sound 
    tone(piezoPIN, toneBase + ((g_led-ledPINBase)*toneDiff), toneDuration);
      
    // wait a specific period of time before the next iteration
    delay(delayPeriod);
  }
  

The arduino IDE is extremely simple to use - the "scratchpad" is where you simply write some C++ code and you can verify and deploy to the device when it is connected via USB cable. While the size of arduino applications seems to be limited to 32,256 bytes (assuming, 32kb not including the bootstrap) you can still do a lot with the device once you figure out how to hook up the sensors and components to the breadboard.

I think I will have more fun on these boards once the LCD (240x320) and Gameduino shields I ordered the other day turn up - there is this crazy satisfaction about receiving a small package in the mail and getting that warm fuzzy feeling like it is xmas every day with gadget madness. Must be the inner geek in me screaming to come out!

UPDATE
I implemented a small binary clock using the exact arduino configuration.

• arduino-binary_clock.txt
• arduino-rolling_leds.txt (same code as shown above)