Guest post: Wise Clock 3/4 Apr-2012 software release

Updated Apr 20/2012
David M. mentioned an important detail: if you try to compile with Arduino 1.0 on Mac OSX  you will get the error "You can't have a cpp file with the same name as the sketch". The quick fix is to change the name of the file WiseClock4.ino (to TheClock.ino, for example). Interestingly, although it makes sense, this error does not show in Windows.
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Here is the email I received from Mike, who took on the challenge to fix and improve the code for Wise Clock 3/4, available here. Thanks Mike, keep up the great work!

My note: If you don't feel very confident about upgrading the software on Wise Clock 3/4, please do not do it.


I combined WiseClock3/WiseClock4 into one distribution, creating a WiseClockVer.h file with a
   #define _WISE_CLOCK_VER 3
line.  HT1632.cpp and Buttons.h include WiseClockVer.h, and use lines like
  #if _WISE_CLOCK_VER > 3
  #define HT1632_CLK      15      // clock pin (pin 2 of display connector)
  #else
  #define HT1632_CLK      11      // clock pin (pin 2 of display connector)
  #endif
That way the same distribution can be used for Wise Clock 3 or Wise Clock 4, and only one line has to be changed.

I found some places where over 100 bytes of data are copied into msgLine, overflowing the buffer.  Rather than just increasing the size of QUO_MSG_LEN, I changed all references to QUO_MSG_LEN to use MAX_MSG_LEN instead.

When reading a quote line a prefix character of Control-R (^R) will display the quote in red.  A prefix character of Control-O (^O) will display the quote in orange.

I removed all floating-point operations in favor of scaled integers.  For AppPong I scaled by 256, for temperature I scaled by 4 as the DS3231 is only accurate to 0.25 degrees.  I found that when the high and low temperatures were scaled by 10 and displaying farenheit that today's high could be 0.1 degree lower than the current temperature due to round-off errors.  These errors are avoided by saving the temperature scaled by 4 instead of 10.

I added a DST flag to indicate Daylight Savings Time is in affect.  DST+ sets the flag and advances the hour by one, DST- clears the flag and retards the hour by one.  The DST settings in the message file are still honored, setting the flag and incrementing the hour (if the DST flag is clear) or clearing the flag and decrementing the hour (if the DST flag is set) at the appropriate time.
The DST flag is used in the UTC code so the UTC offset is set once.  There is no need to change the UTC offset when Daylight Savings Time starts or ends.

I changed the sign of the UTC offset, so '-5' is now correct for Eastern Standard Time.  UTC + offset = current time.
Negative UTC offsets could not be restored properly, as -5 when retrieved would come back unsigned as 250.  I worked around the problem by adding 24 when saving to EEPROM and subtracting 24 when reading the EEPROM.

I changed the resolution of AppTimeLived's makeTime() from seconds to minutes.  The displayed seconds are calculated by taking the delta of the current second specified birth second, so makeTime() does not need the extra accuracy.  This change allows the offset to be calculated from 1900 instead of 1950.  With a second resolution and base of 1950 makeTime() would wrap in 2018.  With a minute resolution and a base of 1900 makeTime() won't wrap for another ~4000 years.

I changed the DEMO mode so it cycles through several display modes.  The number of minutes to display each mode is selected on the first screen after DEMO is selected, going from 0 minutes to 9 minutes.  Ten seconds is added to the cycle time, so selecting "0" goes to a new display every ten seconds.
The original lines Demo is only displayed for ten seconds, regardless of the selected cycle time.  The LIFE demo is displayed for fifteen seconds.
I was going to have AppWords as one of the demos, but I'd have to in-line most of AppWords' initialization code in the demo code, so I didn't bother.

I changed AppLife so it now wraps over the edges of the display.

I went through AppPong so all display offsets are relative to X_MAX and Y_MAX. As mentioned earlier, floating point math was replaced by scaled integers.  The height of the bat is now a #define and set to 5 instead of the previous version's hard-coded 6.  I settled on a color scheme -- ball and pitch are green, score is red, bats are orange.  I fixed some bugs in the ball prediction code and the 'flip' code (used to put 'english' on the ball).  I changed the 'miss' code to only miss by a few pixels.

The removal of the floating point freed up a lot of space.
It's [the whole sketch] less than 58K bytes.

I'm running the clock now.  The only issue is the year's high temperature needs to be re-initialized.  It was scaled by 10, now we expect it to be scaled by 4.  The nightly comparison won't save a new high temperature because the old one now is 2.5 times higher than it should be.  New clocks won't have the problem, but upgrading an existing one will.  The yearly low temperature isn't a problem because the scaled-by-four temp will be lower than the scaled-by-ten temp (unless your low is less than 0 C).  The work-around is easy, just set the year back by one overnight.  In the morning the yearly high/low temp will be reset.  The yearly high/low is only displayed in the "STATS" app anyway.


I corrected the life neighbor calculations.  The neighbor calculation used to be the sum of the colors for the eight neighbors.  This works when only green (1) is used, but when the colors are randomized the neighbor calculations are wrong, as some neighbors could be red (2) or orange (3).  I changed the color selection to use green for birth, orange for steady-state, red for dead.  The neighbor calculation now looks at the least significant bit of the color.  Green and Orange both have the lsb set, so this works well.

A quote-line can now be any length.  The quote buffer is replenished when processing is within 24 characters from the end of the buffer and the line was truncated.  Additional characters are tacked on to the end of the remaining 24, with no interruption.  This will repeat until the entire line has been processed, no matter how long the line is.  Reminders and Messages are still limited to 100 characters, and the lines in the Words files are still limited to 175 characters.