The power packed I2GPS board (photo by Brian Krontz)

Here is a sneak preview into a product we are working on: the I2GPS.  The I2GPS is a slightly modified I2SD.  The only difference is that Anool added an interface to the hacker friendly Fastrax UP501 GPS reciever.  We think we have found a winning combination: for processing an arduino compatible ATMEGA328, a micro SD for massive amounts of storage, the ChronoDot (macetech.com) compatible DS3231 real time clock and finally the UP501 GPS module.  This board also has on board voltage regulators for both 3 and 5 volts and plenty of break out pins for hackablity.

The initial application is a GPS disciplined timing reference that acquires and maintains 1 microsecond timing accuracy.  This even works in the basement of my house!  When the GPS signal is lost, the RTC maintains 1 millisecond / hour accuracy on its own.  I know that for many DIY apps this is overkill, but we are building a race timing system that requires this level of accuracy.

But why stop there?  With GPS in hand, we can determine the timezone!  This sounds like a piece of cake, but turned out to be a pretty tricky problem.  There are literally thousands and thousands of individually defined timezones!  In fact there are 27,732 defined in the generously provided shape file by Eric Muller at http://efele.net/maps/tz/world/.

The good news is that I found a Java library that looks up time zone by GPS fix, the bad news is that they wanted $2000 for it!  With Eric’s shape file in hand, and an open source shape file library written in Python only one more piece of information was missing: the list of GMT offsets which was thankfully provided by Wikipedia.

We had an internal debate here at WyoLum.  Kevin Osborn found an elegant solution based on zip codes that worked for the United States but was not easily extendable to the rest of the world.  While driving to work last week, I realized that we could easily store the timezone for every  single latitude and longitude in a fine grid over the Earth on the SD card.  And why not?  With a measly 1GB SD card, the I2GPS has way more memory than processing power.

Within an hour I had a function (albeit non optimized) that could look up the timezone for any latitude, longitude pair.  I guess that answers the make/buy decision that the propriety code begged me to consider.  Within 5 hours I had a database of latitude, longetude, timezone, daylight time that was about 22 MB in size.  Large for a micro, but fits with ease onto a 1GB card.  I used 1 degree latitude bins and 0.1 degree longitude bins for about 648000 points.

For implementation reasons I broke the large file up into manageable chunks by latitude and put them on the micro SD card.  Finally I wrote a lookup routine for the micro controller that looks up the timezone by latitude and longitude.

Aahhh setting your awesome word clock for daylight savings time is so yesterday…

Code and hardware will be available soon.

ClockTHREEjr by WyoLum is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Based on a work at wyolum.com.
Permissions beyond the scope of this license may be available at wyolum.com.

You are probably already asking yourself what is WyoLum Text Format, or WTF? for short.  Let me answer that for you.  The WyoLum Text Format is a file format that defines the  LED sequencing for ClockTHREEjr.  This makes it easy for anyone to define a new language or dialect for ClockTHREEjr without programming.  Our LINGUIST backers from Kickstarter and others have already used WTF to define 10 languages and variants.  Here, we show how it works through an example: Dutch_v1.  (David Pincus’ and Roel Paes’ clear and simple rendition of the LED sequence that defined his Dutch variant was the spark that led to WTF).

In your favorite spreadsheet program (we use Google Docs), start by defining the characters in the 8×16 LED grid.

  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
0 h e t r i s p v i j f b t i e n
1 k w a r t w i n t i g n v o o r
2 o v e r v h a l f w t w e e n b
3 d r i e v i e r v i j f z e s b
4 z e v e n e g e n a c h t i e n
5 e l f t w a a l f c u u r f ' s
6 o c h t e n d s m i d d a g s a
7 d p a v o n d s n a c h t s j s

The first character “h” (in the upper left hand corner of the grid) goes in cell “C2” so that the character grid covers the range(C2:R9).

Next we define the grid vocabulary (the individual words that the faceplate is capable of displaying) .  A “word” here means a group of horizontally adjacent cells which is identified by three numbers: starting row, starting column, and length.  Words are allowed to overlap if they share common letters.  For instance “twee” and “een” at the end of row number 2 share “ee”.  The word definitions start in cell V1.  The number of words in the vocabulary is arbitrary although there are more efficient ways of stroring the LED sequence if more than 128 words are used.  In practice, we have not required more than 45 words in any variant.  If we include the labels in column U and the translations in rows 3 and 4, the Dutch_v1 words start out like this:

StartRow	0	0	0	0	1	1	1	2	2	...
StartCol	0	4	7	12	0	4	12	0	5	...
length		3	2	4	4	5	7	4	4	4	...
Dutch		het	is	vijf	tien	kwart	twinig	voor	over	half	...
Translation	it	is	five	ten	quarter	twenty	before	after	half	...

Although it is not absolutely essential, the words should appear in the same order as on the faceplate.  This allows Simulate.py (discussed later) to print the words corresponding to each time as well as to display the time on the faceplate.

Next we define when each word should light up.  There are 288 5-minute time increments in 24 hours.  Therefore, the LED sequencing matrix has 288 rows and one column per word.  In Dutch_v1 there are 27 words, so the LED sequencing matrix is 288 rows by 27 columns starting in cell V6.  In Dutch “het is twaalf uur ‘s nachts” means “it is mignight”.  This is indicated in the first row of the LED sequencing matrix by copying each word in the pharse “het is twaalf uur ‘s nachts” to the first row, in the appropriate cell.  Please refer back to the Google doc for clarification.  Even though this is really a binary (on/off) matrix we use the whole word to indicate that it should be lit so that it is easty to read the time phase right off the spreadsheet.

The LED sequencing matrix displayed for English_v3.

Finally we define the “minutes hack” leds and sequencing.  Some people love the minutes hack, others hate it.  Basically it allows the clock to display more precise time than every five minutes, but not in words.  We call it the “minutes hack” because when Anool and I made our first word clock, the “Worduino” the minute leds were an after thought.  Traces needed to be cut and extra wires needed to be added.  It really was a hack.  Since then we have designed in the “minutes hack” but the name as stuck.

You can have as many “minute” leds as you want.  The Hebrew_v1 variant uses the whole bottom row as minute LEDs, but just four works well too to show how many minutes past the displayed time have elapsed.  A minute LED is a single cell specified by a row and a column of the matrtix.  Also a variant may have any number of minute hack “states”.  The transitions are timed so that the entire sequence is displayed every five minutes.

The number of minute LEDs is specified in cell V294.  Put a zero here if your variant does not use minutes hack LEDs.  The number of minutes hack states is specified in cell X294.  Again, put a zero here if your variant does not use minutes hack LEDs.

Since Dutch_v1 does not used the minutes hack feature, we use Shai Aharonov’s Hebrew_v1 as an example.

n_min_led	16	n_min_state	20

Including the labels the LED locations for this variant look like this (the first 7 is located in cell V295):

minute row	7	7	7	7	7	7	7	...
minute column	0	1	2	3	4	5	6	...

The next n_min_state rows (20 in this case) define when each minute led is lit.  Put an “X”s in the appropriate cells.

Continue reading →

Announcing two German versions of ClockTHREEjr.  The are open to review on the forum.

German_v1 includes words like “mittags” “nachts” und “abends”. We were one letter too short to include them all as we would like so we had to make the compromise of sharing the “s” on “nachts” with mittags. so “nachts” reads

“NACHT__________S”

German_v2 only tells the time. The words are numerically ordered so the progression flows more naturally. None of the words share any letters.

Each version is available as an animated GIF file or a zipped directory of images.  Coming up:Esperonto and French.

Roger, who initiated the explosion in number of German veriants has contributed this table clarify the differences between the them.  Thanks Roger!

Given the recent success of ClockTHREEjr, we thought it was appropriate to point out our partnerships, without whom ClockTHREEjr would not be possible.

Volunteer Partnerships:  These partners have not asked for any compensation for supporting ClockTHREEjr.

• Wise Time With Arduino, (FlorinC) http://timewitharduino.blogspot.com/ — The original impetus for bringing the costs down on ClockTHREEjr and project lead
• Brian Krontz, http://www.briankrontz.com/ — Photographer.  Brian indicated in no uncertain terms how much room for improvement we had in the photographic arts!  We challenged him to “show us what we were missing” and that he did.

Please visit their websites and price them on your next project.  We have found them to be reliable and more affordable than all of their competitors.

• Hines Design Labs http://angushines.com — Custom CNC work, and laser cutting.  Angus re-designed our faceplates to be much more manufacturable and flexible.  We have priced other services and have found Angus Hines to be literally half the cost.
• Seeed Studio, http://www.seeedstudio.com/depot/ — PCB, kits, assembly.  We were shocked by the discounts we could receive from Seeed Studio if we could buy in quantities of 100 or more.