Charliexplexed LED Clock – Arduino

1. A standalone arduino
2. 60 White LEDs – 5mm
3. 9 resistors – 110 Ω
4. WS2812B RGB LED strip – 60 LEDs
5. RTC Module – DS1307
6. Some headers, wires, capacitors, etc
7. 12V – 800mA adapter
8. CP2102 USB-to-TTL (the RST pin on the CP2102 is not for resetting the arduino – you have to solder a wire to the DTR pad on the PCB – which sends a reset signal to program the arduino. This has to be connected to the reset pin through a 104 capacitor) or Arduino to program the standalone processor as discussed in the previous post.

Prepared the above plan to solder the charlie-plexed LEDs using a stripboard: The blue numbers in the above diagram are due to errors while soldering (and what a pain it was…).

The rest of the circuit is simple (see schematic):

1. Pins 3-11 of the arduino to the above circuit
2. Pin 12 to data pin of the LED strip
3. SDA and SCL pins to the RTC module’s SDA and SCL pins.

For more details on creating a standalone arduino please see:

http://dushyant.ahuja.ws/2013/10/standalone-arduin…

#include "Wire.h"
#include "RTClib.h"
#include "FastLED.h"
byte LEDs[][2]={ // Array to define the Charlieplexed LEDs
  {3,4},
  {5,6},
  {7,8},
  {9,10},
  {4,3},    // 5
  {6,5},
  {8,7},
  {10,9},
  {3,5},
  {4,6},    //10
  {7,9},
  {8,10},
  {5,3},
  {6,4},
  {9,7},    //15
  {10,8},
  {3,6},
  {4,7},
  {5,8},
  {9,11},    //20
  {6,3},
  {7,4},
  {8,5},
  {11,9},
  {3,7},    //25
  {4,8},
  {5,9},
  {6,10},
  {4,9},
  {8,4},    //30
  {9,5},
  {10,6},
  {3,8},
  {7,3},
  {5,10},    //35
  {6,11},
  {8,3},
  {9,4},
  {10,5},
  {11,6},    //40
  {3,9},
  {4,10},
  {5,11},
  {9,3},
  {10,4},    //45
  {11,5},
  {3,10},
  {4,11},
  {10,3},
  {11,3},    //50
  {11,4},    
  {4,5},
  {6,7},
  {8,9},
  {10,11},  //55    
  {5,4},
  {7,6},
  {9,8},
  {5,7},
  {6,8}      //60
};

#define NUM_LEDS 60
#define DATA_PIN 12
CRGB leds[NUM_LEDS];
byte lastmin;
RTC_DS1307 rtc;

void setup() {
  // put your setup code here, to run once:
  AllOff();
#ifdef AVR
  Wire.begin();
#else
  Wire1.begin(); // Shield I2C pins connect to alt I2C bus on Arduino Due
#endif
  rtc.begin();
  lastmin=0;
  LEDS.setBrightness(128);
  FastLED.addLeds<WS2812B, DATA_PIN, GRB>(leds, NUM_LEDS);
  //effects();
  //Serial.begin(57600); 
}

void loop() {
  // put your main code here, to run repeatedly:
  DateTime now = rtc.now();
  // Serial.print(now.hour(), DEC);
  if(( now.second() == 0)){
    effects();
  }
  if(now.minute() != lastmin){
    for(int i=0; i<now.minute();i++)
      leds[i] = CRGB::Purple;
    leds[((now.hour())%12)*5] = CRGB::Red;
    FastLED.show();
  }
  LEDOn(now.second());
  delay(900);
  AllOff();
  //leds[((now.hour())%12)*5] = CRGB::Black;
  //leds[now.minute()] = CRGB::Black;
  //FastLED.show();
  delay(100);
  //}
}

void LEDOn(byte n){
  AllOff();
  pinMode(LEDs[n][0],OUTPUT);
  pinMode(LEDs[n][1],OUTPUT);
  digitalWrite(LEDs[n][0],HIGH);
  digitalWrite(LEDs[n][1],LOW);
}

void AllOff(){
  for(int i=3;i<=11;i++){
    pinMode(i,INPUT);
  }
}

const int colorWheelAngle = 360 / NUM_LEDS;

void effects(){
    uint8_t color[3];
  for (int i = 0; i < 360; i++) { 
    for (int j = 0; j < NUM_LEDS; j++) {
      getRGB((i + (j * colorWheelAngle)) % 360, 255, 150, color);
      leds[j]=CRGB(color[0], color[1], color[2]);
    }
    FastLED.show();
    delay(1);
  }
  for (int i = 0; i < NUM_LEDS; i++) {
     leds[i] = CRGB::Black;
  }
  FastLED.show();
}

// Gamma values used to convert HSV to RGB
PROGMEM const byte dim_curve[] = {
 0, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3,
 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4,
 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6,
 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8,
 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11,
 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 15,
 15, 15, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 20,
 20, 20, 21, 21, 22, 22, 22, 23, 23, 24, 24, 25, 25, 25, 26, 26,
 27, 27, 28, 28, 29, 29, 30, 30, 31, 32, 32, 33, 33, 34, 35, 35,
 36, 36, 37, 38, 38, 39, 40, 40, 41, 42, 43, 43, 44, 45, 46, 47,
 48, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62,
 63, 64, 65, 66, 68, 69, 70, 71, 73, 74, 75, 76, 78, 79, 81, 82,
 83, 85, 86, 88, 90, 91, 93, 94, 96, 98, 99, 101, 103, 105, 107, 109,
 110, 112, 114, 116, 118, 121, 123, 125, 127, 129, 132, 134, 136, 139, 141, 144,
 146, 149, 151, 154, 157, 159, 162, 165, 168, 171, 174, 177, 180, 183, 186, 190,
 193, 196, 200, 203, 207, 211, 214, 218, 222, 226, 230, 234, 238, 242, 248, 255,
};

/*
 * Code taken from <a href="http://www.kasperkamperman.com/blog/arduino/arduino-programming-hsb-to-rgb/" rel="nofollow"> http://www.kasperkamperman.com/blog/arduino/ardui...</a>
 * hue ranges from 0 to 360
 * sat is from 0 to 255
 * val is from 0 to 255
 */
void getRGB(int hue, uint8_t sat, uint8_t val, uint8_t colors[3]) { 
 /* convert hue, saturation and brightness ( HSB/HSV ) to RGB
 The dim_curve is used only on brightness/value and on saturation (inverted).
 This looks the most natural. 
 */

 val = pgm_read_byte(&dim_curve[val]);
 sat = 255 - pgm_read_byte(dim_curve[255-sat]);
 int r;
 int g;
 int b;
 int base;

 if (sat == 0) { // Acromatic color (gray). Hue doesn't mind.
 colors[0]=val;
 colors[1]=val;
 colors[2]=val; 
 } else { 
    base = ((255 - sat) * val)>>8;
    switch(hue/60) {
    case 0:
        r = val;
        g = (((val-base)*hue)/60)+base;
        b = base;
    break;

    case 1:
        r = (((val-base)*(60-(hue%60)))/60)+base;
        g = val;
        b = base;
    break;

    case 2:
        r = base;
        g = val;
        b = (((val-base)*(hue%60))/60)+base;
    break;

    case 3:
        r = base;
        g = (((val-base)*(60-(hue%60)))/60)+base;
        b = val;
    break;

    case 4:
        r = (((val-base)*(hue%60))/60)+base;
        g = base;
        b = val;
    break;

    case 5:
        r = val;
        g = base;
        b = (((val-base)*(60-(hue%60)))/60)+base;
    break;
    }
    colors[0]=(uint8_t) r;
    colors[1]=(uint8_t) g;
    colors[2]=(uint8_t) b; 
  }  
}