Who needs a Software Real Time Clock?

Thanks for the feedback. I have uploaded the new code to the playground. Please do give it a try and also verify if the directory structure for the example works for you.

mem:

I will try the new DateTimeStrings.cpp, but with the older version commented out as you suggested my sketch still freezes after running a short time and then jumps to some new random time. The other sketch you asked me to try runs for 24 hours without problems. I am using a Mac for development. This is all still on 0011

Hi hotcarrier, Let me know how you get on with the DateTimeStrings code in the playground. It should be ok with either 0011 or 0012

mem, i checked and it's ok!

mem:
I tried the latest libraries from the Playground and the behavior in the same sketch is the same. Runs for while, freezes and jumps to new random time restart.

Hotcarrier, did you check that the latest version is being compiled?

Go to the DateTimeStrings library directory on your computer and open the file DateTimeStrings.cpp to verify that it has a comment indicating Version 1.0b 12 Nov 2008

Delete the DateTimeStrings.o file so that the code will be rebuilt and recompile your sketch and try again.

mem:
Good news. I had done what you suggested and it still did not run on 0011. But I moved to 0012 and it just ran correctly overnight! I will investigate and see if I see anything further on 0011, but probably just
move to 0012 for this project. Thanks for your help.

mem:
After an absence I got back to this project and this time was able to get it working on a different mac with no problem on arduino 11. It runs for days with no problems. Now I cannot get it to compile on arduino 12 as it consistently is giving stdlib.h errors. I have tried the newest playground files. Anything you could point me to would be appreciated.

Hi hotcarrier, the code in the playground compiles without problem under 0012 on my machine. Have you tried to compile the playground example sketch? If that compiles ok then perhaps post your sketch, it maybe something there causing the problem.

Good Luck!

I am sure that I am doing something dumb here... but I am running into a mental block or some such craziness trying to get the hour component to show up in 12hr increments rather than the 24hr setup.
The Date Time code is working quite well - so I know it is something I am not doing right - I have tried to assign the DateTime.hour like so:

hours = (DateTime.Hour);
if (hours > 12) {hours = hours - 12;}

So... I am pretty sure it is something dumb I am doing, but at this point I cant figure it out.

I have the minutes and seconds working well - I am breaking out the tens and ones of each one, and displaying on a 7 segment LED setup.

Help is greatly appreciated! :smiley:
Thanks

to convert to 12 hour format you do the following:
between 0000 and 0059, add 12 hours
between 0100 and 1159, straight conversion to AM
between 1200 and 1259, straight conversion to PM
between 1300 and 2359, subtract 12 hours

Here is a function you can put in your sketch that will convert the 24 hour format from the library to 12 hour format

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

Determining AM/PM is easier, if the 24 hour value is < 12 its AM , otherwise its PM

I will add these functions to the next release of the library, let me know how you get on.

Thanks for the code :slight_smile:

edit - fixed my code, and it works great now! :smiley:

Greetings! I'm just starting to mess around with the Arduino and I ran into a problem with the SetArduinoClock example from the DateTime library. Specifically, the Processing part of the example that reads a time code back from the Arduino to display a small analog clock on screen seems to be mangling the timecode header byte. The byte is sent from the board as 255 but ends up getting mangled by the call to myPort.readStringUntil(LF);

I came up with some alternate code that works and I wanted to share it.

void serialEvent(Serial p) {
byte[] inBuffer = myPort.readBytesUntil(LF);
if(inBuffer == null || inBuffer.length == 0) {
return;
}
if(inBuffer[0] == byte(TIME_HEADER)) {
int val = 0;
long time = 0;
for(int i = 1; i <= 10; i++)
time = time * 10 + (inBuffer - '0');

  • UpdateClock(time);*
  • } else {*
  • print(new String(inBuffer));*
  • } *
    }[/font]
    I'm running Processing V. 1.03 on a Mac. I'm posing this here as the DateTime wiki page linked to this forum. I also couldn't send a direct message to the PM contact as I have a posting count of 0...until I click Post in 3, 2 , 1.... :slight_smile:

Hi Dave, what symptoms are you seeing? I am running processing 1.01 (on windows) and the playground code works fine for me. But I am happy to make the change from strings to a char array if it fixes the problem for you. I am curious however to know what exactly is the problem.

i'm working on arduino severino
it have serial input, so i changed baud rate to 9600
i'm able to upload successfully, but no output from serial port is coming

You don't say if you get output with other sketches.

Try adding a print statement in setup to see if you can get that output
Serial.println("Setup Complete");

If you see that but nothing else then your Arduino is detecting the message to set the time. Make sure both sides are using 9600 baud and that you have selected the correct com port in Processing

I'm still waiting for my first Arduino in the post, so excuse my ignorance...

I'm looking to use the software real time clock in my first project as I need to trigger a function twice a day at certain times. I'm also looking at using the watchdog timer and sleep functions to save energy (http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/).

Are the two compatible, or is there some way to make them compatible? I realise that I might need to use a different sleep mode than that used in the example linked to above (maybe "power save" mode instead of "power down" mode).

Any help would be appreciated!

I had some free time today so I finally got around to allowing my Arduino to sync the DateTime over the internet using the wiznet module. It grabs the time from the NIST server which gives a response like this:

54964 09-05-13 21:01:33 50 0 0  14.3 UTC(NIST) *

From that it was a little bit of work figuring how to convert to unix time, but I got it sorted. The nice thing about using NIST is that it also indicates if it is daylight savings or standard time so the time will always be correct. No adjustment needed or watching for specific dates. I currently update the time every twelve hours. With the price of the wiznet module around $16 I think this trumps having a RTC because of the other things you can do with ethernet.

Currently, this is in a pretty large program on my Sanguino. If there's interest I could put together an example sketch that simply updates the time from NIST.

Are the two compatible, or is there some way to make them compatible?

The majority of the sleep modes on the AT90USB162 processor seem to shut off all the timers (except the watchdog timer). This means millis stops running.

Hopefully this will help...
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1240918097

Good luck,
Brian

Thanks Brian,
I've worked out a new control algorithm that doesn't require date/time, so now I just need to put the arduino to sleep and wake it every few minutes to conserve energy. Looks like the thread you've linked to will do the trick.

Cheers,
Todd