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
BinBoo-v1 PCB
- (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:
The core design came from the Arduino Duemilanove schematic. There were changes to the FTDI chip in order to make it work correctly.
LED Panel:
BinBoo – LED Panel Front
How BinBoo’s LED Matrix is Wired
The LED panel is constructed with all Anodes connected to VCC. The cathodes each connect to an output of the TLC5940. Due to a design change (from straight binary to BCD), the BinBoo Controller board does not have enough outputs connected to header pins.
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
Acknowledgements
(Links to be added)
1. Arduino Project
3. My first Arduino TLC5940 Project Page
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