Help with binary clock conversion from 24hr to 12hr

Projects Programming
1

Hi,
My wife bought me a binary clock shield that fits onto an Arduino Uno for Christmas last year. The binary clock works great but it is in the 24Hr. format. I would like to have it display only 12Hr. format. I contacted the author and designer of the shield and back in January, he told me he would be able to convert the code to 12Hr. format in a couple weeks. After several more e-mails, promises of a couple weeks I still don't have the code for a 12Hr. format. I have spent hours trying to figure out how to convert it but I am not a programmer. Below is the link to the code on Github.
If anyone can help, I would really appreciate it.

Thank You,

Ron

2

Just a shot in the dark, but try to find and replace this function with this code:

void getAndDisplayTime() 
{
    // Read time from RTC  
    t = RTC.get();
    // Convert time to binary format and display     
    int hours = hour(t);
    if (hours > 12) hours -= 12;
    convertDecToBinaryAndDisplay(second(t), minute(t), hours);
}

No idea, but it's worth a try.

3

After this part:

void convertDecToBinaryAndDisplay(int bottomRow, int middleRow, int upperRow) 
{  
    bool oneBit;

Put:

  // Switch from 24-hour time to 12-hour time
  if (upperRow > 12)
    upperRow -= 12;
4

That will probably fix the display, but doesn't address user interface for setting time and alarms. Might also want to repurpose MSB LED of hours for AM/PM Indicator since only need 4 bits for that now. Will probably take several iterations to get it completely right.

5

Slight variation on that:

int hour = hour(t);
if (hour == 0) {
  hour = 12; // 12 midnight
}else if( hour > 12) {
  hour = hour - 12;
}

Midnight is 12 o'clock in the 12-hour system.
You could also add a flag to indicate AM/PM and use it to turn on some indicator:

int hour = hour(t);
bool pm;
if (hour == 0) {
  hour = 12; // 12 midnight
  pm = false;
}else if( hour > 12) {
  hour = hour - 12;
  pm = true;
}
if (pm) .....

Not sure whether I would do that in void convertDecToBinaryAndDisplay() or getAndDisplayTime(), but I suppose either could work for the display at least, but in the case of the latter you might want to pass the pm indicator to the former.

7

Thank you for the response. I added the code and it did convert to 12hr. Thank You. When I set the time, and scroll thru the hours at 12 o'clock, none of the LED light but then I scroll all thru the time (1,2,3...)and get back to 12 o'clock, the 12 is displayed. It displays every other 12 o'clock. Any ideas how to fix that. I am so happy that I don't have 24Hr. clock anymore. Thank you

8

Sounds like the midnight problem I mentioned. When you get to 23:59:59 on the 24hr clock it then rolls over to 00:00:00 so you won't get any LEDs light up. That's why I suggested an additional line to deal with that. Just add the following to johnwasser's example:

if (upperRow == 0)
  upperRow = 12;

It should then roll over to 12:00:00

9

That did it!!!! Thank you so much for all of the suggestions. This has been on my mind since last Christmas.

Thanks to all again,

Ron

10

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