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Topic: Stopwatch with Pause/Lap  6 digit 7 seg LED. HELP! (Read 123 times) previous topic - next topic

Warren Reeve

Hi Codey, yes I have tried that.. I was originally timing it from my mobile phone but after all the controversy I though it would be a good idea to double/treble check how accurate it was.
I checked my mobile phone against my PC and it was accurate to it and then I checked the both of them against a hand held stopwatch/lap timer.. all 3 ran the same speed. My arduino is approx 4 weeks old and is an Arduino Uno.

Hope that helps.  :-/

Coding Badly

#41
Dec 30, 2010, 12:59 am Last Edit: Dec 30, 2010, 01:00 am by bcook Reason: 1

I believe that the Uno has a resonator and... (4.66 / (25 * 60)) * 100 = 0.31 % ...is about the typical accuracy for a resonator.

But, you should have someone else confirm what I'm saying.

I also suggest you try to get a few other Uno users to confirm what you're seeing.  The shiftOut calls can be replaced with Serial.print calls.

Warren Reeve

Code: [Select]
if (ones_seconds == 10){
     ones_seconds = 0;
     [glow]hundredths = hundredths +7;[/glow]   // Speed up the clock!
       tens_seconds = tens_seconds +1;
   }


Would this be acceptable as a fix? (shown previously)
Basically, if the Uno is out a little would it not be ok to give it a little back each loop? I don't want to bad code or anything like that but if the internal time is not accurate I don't see much choice in this situation.
Also please keep in mind that I am a complete novice with all this.  :P

PS. Time difference after 1 hour = 11 seconds.  :-[

Coding Badly

Quote
Would this be acceptable as a fix? (shown previously)

Only you can decide.  If what you are trying to build is "for entertainment purposes" then I can't imagine a little tweak being a problem.  If money or pride is involved, you may end up involved in some heated arguments (or fights).

Quote
Basically, if the Uno is out a little would it not be ok to give it a little back each loop?

Certainly.  But you should first confirm that your Arduino really does have a resonator instead of a crystal.

Warren Reeve

Yes, I agree.. lap times can become a very heated conversation at times.. I would certainly not like to be the guy who made the racer go slower...!!! >:(  haha.. then you would see some fast laps as I left the building!! Lol.
Quote
But you should first confirm that your Arduino really does have a resonator instead of a crystal.

If anyone reading this can shed any light on this.. please do otherwise I will try and get an answer from Arduino or someone else as soon as I can.
Thanx again to Robert and Codey for all your time and help. Really appreciated.  :)

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