BinBoo – Binary Clock

Abstract

Binary + Bamboo = BinBoo.  This project is my first attempt at making a laser-cut enclosure.  Ponoko was used to cut the project which holds itself together.  The LEDs are driven by an Arduino-based clock that incorporates a RTC1307, FTDI chip, ATmega328, and TLC5940.

Electronics

• (12) – Bright Blue 5mm LEDs
• (13) – Jumper Wires
• (1) – BinBoo Controller Board with:
  • (1) – ATmega328
  • (1) – TLC5940
  • (1) – FTDI 232
  • (Various) Decoupling capacitors
  • USB Mini-B Port

Schematic:

Firmware

The code is based on the TimeRTC example from the Arduino Time Library.  In order to set the time, a serial monitor must be used.  The syntax is simplistic:  “T<seconds since epoch>”.  The UNIX time library provides this value rather easily. Code was added for: startup effect, fading between time changes, determining the BCD of the time, and getting time from the RTC. The startup effect is useful because it helps to identify wiring mistakes since it fades the LEDs in sequence. Code as of 5/19/2012:

/*
 *
 *  BinBooV2
 *  Created by:  James C Lewis. [email protected]
 *  www.baldengineer.com
 *
 * BinBoo is a Binary clock made out of bamboo materials. The electrical hardware includes
 * a ATmega328, DS1307 RTC, and a TLC5940. These chips are connected to 11 LEDs.
 *
 * from bash:  date +%s (for number of seconds)
 * CDT offset: -18000
 * CST offset: -21600
 */
#include <Time.h>
#include <Wire.h>
#include <DS1307RTC.h>
#include <Tlc5940.h>

#define EPOCH_OFFSET -18000
#define TIME_MSG_LEN   11
#define TIME_HEADER 'T'
#define TIME_REQUEST 7
#define WAIT_INTERVAL 5000

#define DAY_BRITE 512
#define NIGHT_BRITE 128

unsigned long waitMillis;

void setup() {
  Serial.begin(9600);
  Serial.println(F("BinBoo Release 0.2 - James Lewis ([email protected])"));
  Serial.println(F("Use date +%s to get current time in seconds"));
  setSyncProvider(RTC.get);  // grab time from the RTC
  if(timeStatus()!= timeSet)
    Serial.println("Unable to sync with the RTC");  // not really sure who is going to see this one.. ;)
  else
    Serial.println("RTC has set the system time");  

  Tlc.init();
  Tlc.clear();
  Tlc.update();

  waitMillis = millis() + 1000;   // setup first crossing point
  startUpSequence();
}

void loop() {
  int previousTime=0;
  int currentTime=0;
  while(1) {      // want to avoid making currentTime/previousTime global
    if (Serial.available())
      processSyncMessage();
    if ((long)(millis() - waitMillis) >= 0) {     // need to cast to signed math...
      printTimeDate();
      currentTime = calculateTimeBits();
       setTLCtime(previousTime, currentTime);
      previousTime = currentTime;
      waitMillis += WAIT_INTERVAL;  //sit around for another second.
    }
  }
}

void setTLCtime(int previousTime, int currentTime ) {

  if (previousTime == currentTime)    // time hasn't changed, so don't do anything
    return;

  int bright = 0;    // what is the max brightness, based on the time.
  if ((hour() >= 6) && (hour() <= 18))
    bright = DAY_BRITE;
  else
    bright = NIGHT_BRITE;

  for (int i=0; i<=bright; i++) {
    int fadeAmount = 0;  // each look of the bright for, will be to fade up/down the leds
    for (int j=0; j<12; j++) {   // this loop determines which direction and intensity of fade
      switch (bitRead(previousTime, j) - bitRead(currentTime,j)) {
      case 0:  // no change, the led alone
        if bitRead(currentTime,j)
          fadeAmount = bright;
        else
          fadeAmount = 0;
        break;
      case -1: // turn the led on
        fadeAmount = i;
        break;
      case 1: // turn the led off
        fadeAmount = bright - i;
        break;
      }
      Tlc.set(j, fadeAmount);
    }
    Tlc.update();
    delay(1);
  }
}

int calculateTimeBits() {
  int hours = hourFormat12();
  int minutes = minute();
  int timeLEDs=0;

  timeLEDs = hours;
  timeLEDs = hours << 8;

  timeLEDs += (minutes/10)<<4;
  timeLEDs += minutes%10;

  if (isPM())
    bitSet(timeLEDs, 11);

  return timeLEDs;
}

void printTimeDate() {
  printTime();
  Serial.print(" ");
  printDate();
  Serial.println("");
}

void printTime() {
  Serial.print(hourFormat12());
  printDigits(minute());
  printDigits(second());
  Serial.print(" ");
  if (isAM())
    Serial.print("AM");
  else
    Serial.print("PM");
}

void printDate() {
  Serial.print(month());
  Serial.print("/");
  Serial.print(day());
  Serial.print("/");
  Serial.print(year());
}

void printDigits(int digits){
  // utility function for digital clock display: prints preceding colon and leading 0
  Serial.print(":");
  if(digits < 10)
    Serial.print('0');
  Serial.print(digits);
}

void startUpSequence() {
  for (int j=0; j<12; j++) {
    Tlc.clear();
    for (int i=0; i<(DAY_BRITE+1); i=i+32) {
      Tlc.set(j, i);
      Tlc.update();
      delay(10);
    }
    for (int i=DAY_BRITE; i > 0; i=i-32) {
      Tlc.set(j,i);
      Tlc.update();
      delay(10);
    }

  }
}

void processSyncMessage() {
  // if time sync available from serial port, update time and return true
  if (Serial.available() >=  TIME_MSG_LEN ) {  // time message consists of a header and ten ascii digits
    char c = Serial.read() ; 

    if( c == TIME_HEADER ) {
      Serial.print(c);
      time_t pctime = 0;
      for(int i=0; i < TIME_MSG_LEN -1; i++){
        c = Serial.read();
        if( c >= '0' && c <= '9'){
          pctime = (10 * pctime) + (c - '0'); // convert digits to a number
        }
      }
      pctime = pctime EPOCH_OFFSET;  // the define has a math sign in it
      Serial.print(" - ");
      Serial.println(pctime);
      RTC.set(pctime);
      setTime(pctime);   // Sync Arduino clock to the time received on the serial port
      waitMillis += 100;
    }
  }
}

Demonstration

Acknowledgments

(Links to be added) 1. Arduino Project 2. Macetech’s ChronoDot 3.  My first Arduino TLC5940 Project Page