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Topic: 2 foot by 4 foot LED Clock (Read 1 time) previous topic - next topic


Dec 29, 2008, 03:32 am Last Edit: Dec 29, 2008, 03:48 am by b94cast Reason: 1
I built a 2 x 4 foot LED clock for my wife for Christmas.  I used the Seeeduino for the brain, the MAX7221 for the 7 segment driver.  

I did a video of the steps as a kind of 1month+ of building in less than 5 minutes viewing type of movie with music.  

Thought I would share the results - due to the nature of the finished product, it is hard for me to catch it very well on camera - with the flash on, you see through the frosted front, with the flash off, you miss quite a bit of detail - but at any rate - here it is :)

Video http://www.vimeo.com/2656717

some pics of it hung on the wall in my wifes study


Very nice work and great design. I liked how you made the digits - and the background. Nice video too!
"Data is not information, information is not knowledge, knowledge is not understanding, understanding is not wisdom."
~ Clifford Stoll



I LOVE what you've done and woud be very interested in seeing how your arduino code works. Any chance of sharing the code?


Dec 31, 2008, 02:05 am Last Edit: Dec 31, 2008, 02:07 am by b94cast Reason: 1
Thanks!  :D  
The code is really nothing special at this point (outside of the great code already available) - it is this code:
and this code
munged together.  I didnt really do anything special with either piece, but I can clean up the mess and post it if you still want :)
Was in a time crunch (a few hours before christmas kind of time crunch) so I never cleaned the mess of the code up... ;)


Thanks for your reply.

I would love to see your merged code as I have been having a lot of trouble getting my  attempt to work properly. I think seeing your effort would be very useful.


Here the code is - not very cleaned up at all :)
The only thing I would recommend watching out for is the scanlimit section - make sure these settings correspond properly if  you use it.

Code: [Select]
#include <DateTime.h>
#include <DateTimeStrings.h>
//We always have to include the library
#include "LedControl.h"
#define START_TIME  1230393840  // set this to the Unix start time you want (0 is midnight Jan1 1970 UTC)
/*  Now we need a LedControl to work with.
***** These pin numbers will probably not work with your hardware *****
pin 12 is connected to the DataIn
pin 11 is connected to the CLK
pin 10 is connected to LOAD
We have only a single MAX72XX.
LedControl lc=LedControl(12,11,10,1);

/* we always wait a bit between updates of the display */
unsigned long delaytime=500;
unsigned long delaytime1=50;
int countones=0;
int counttens=0;
int counthuns=0;
int countthos=0;
byte hours1;
char minutes = '0';
char seconds = '0';
int secondstens = 0;
int secondsones = 0;
int hoursones = 0;
int hourstens = 0;
int minutesones = 0;
int minutestens = 0;

void setup(){
  The MAX72XX is in power-saving mode on startup,
  we have to do a wakeup call
 /* Set the brightness to a medium values */
 /* and clear the display */
 pinMode (minbutton, INPUT);
 pinMode (minbuttonm, INPUT);
 pinMode (hourbutton, INPUT);
 pinMode (hourbuttonm, INPUT);


void  loop(){
 unsigned long  prevtime;

void showcurtime(){

 byte hours2;
 hours1 = 0;
 hours1 = (DateTime.Hour);
 hours2 = hours24To12(hours1);
 hoursones = hours2 % 10;
 hourstens = hours2;

 if (hourstens > 9) {
   hourstens = hourstens / 10;
 else {
   hourstens = 0;
 secondsones = (DateTime.Second) % 10;
 secondstens = (DateTime.Second);
 if (secondstens > 9) {
   secondstens = secondstens / 10;
 else {
   secondstens = 0;
 minutesones = (DateTime.Minute) % 10;
 minutestens = (DateTime.Minute);
 if (minutestens > 9) {
   minutestens = minutestens / 10;
 else {
   minutestens = 0;
 if (hourstens == 0) {
 else lc.setChar(0,3,hourstens,false);

byte hours24To12(byte hours){
 if( hours == 0 )
   return 12; // 12 midnight
 else if( hours  > 12)
   return hours - 12 ;
   return hours ;


I dont have buttons active at this point for the time adjust, I had salvaged some buttons off of some other stuff, and they were bad.  So for the time being, I set the START_TIME in code to be current time, and update the system.  I have buttons on order - but I am looking at using the metal pieces on the front for touch sensors for time adjust.  


Thanks a million for posting your code. I'm sure I'll find it very helpful and hope to post my finished LED clock sometime soon.

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