# Sticky  A quick presentation of the HAQ-EZChronos experiment



## Catalin

Most of the usual members of the forum did not have the time to follow the (very!) long thread from:

https://www.watchuseek.com/f9/ezchronos-headcount-first-2011-project-start-498121.html

so I will summarize here some of the ideas (and conclusions after 6 months) from there - however *that long thread should remain the 'work place' for that project and any technical question about it, in this thread we should only post about overall conclusions!*

So to make the long story short - ezChronos is a rather inexpensive (currently about 50 US$) digital watch which has the huge advantage that is fully and openly programmable! The details on the watch can be found at:

EZ430-Chronos - Texas Instruments Embedded Processors Wiki

(and also links to TI store from where the watch can still be ordered).

More than one year ago (probably now close to two) when our current moderator ronalddheld (and maybe other members) introduced the watch to the forum I did express the hope that the watch could be programmed as to reach some good accuracy - but unfortunately Texas Instruments had a few months when it was 'swamped' with orders for that kit, and my own watch was delivered (to a friend of mine in US) very late and arrived at me only at some point around December 2010.

Anyway in January 2011 we started to play with the idea of implementing Thermo-Compensation inside that watch - the very first experiments were very scary since the accuracy of the watch from the factory was pretty abysmal (2-4 seconds/*day* :-d), so initially things did not look very promising. However over the long time we have acquired data (and experience), and things got better and better. Most of the general TC part was finished around May-June or so, and since that point we have actually fine-tuned and tested our 'HEQ-ezChronos watches' ;-)

The general numbers so far seems to point to exceptional results - currently it seems that all watches in the experiment are somewhere under 5s/year and at least 3 (out of 4 watches that I know of) are under 1 second/year around room temperature and the difference from room to a more extreme temperature (very hot or in the fridge) seems to be with the right/full calibration under 3-4 seconds/year - pretty impressive given the very low cost of the original watch - however the 'trick' is that a lot of work and time was spent on individually calibrating those watches! (and from what I could see so far, none of the 4 are very close in the precise TC curve to some other watch in the group - maybe since those are from different batches but it is still possible that even watches in the same batch might show a very similar variability).

And in case you would like to also replicate those results - things are now a lot more clear and generally more 'forum experience' exists on the matter, so that should not be very difficult! However it will still mean that you will need one watch, then you will need to do like 6 measurements over 5 days each in order to have the basic TC curve of the watch, and then for another few weeks (2-8) you might need to fine-tune some of the parameters! And of course you will need a Windows (or Linux?) PC connected on the Internet - our 'source of (cheap) precision' is atomic internet time ;-).

Some other quick thoughts on the entire project:

- one other major point that we might clarify over (more) time in this experiment could be quartz aging - most of our initial TC measurements were in the first 3 months of 2011, most of the fine-tuning from May to July, but with very good fine-tuning at this point we can look forward toward December 2011 and then 2012 - and measure at that point any aging (in the quartz and/or temperature sensor) that will take place!

- a lot of other features have been added to the watch - up to the point where not all can be hold at the same time in the limited memory of the watch, and as such we now have like 3 'slightly specific versions' (and is not impossible that more will chome in time) - all have the HEQ-accuracy but one is the *'data-logger'* (which is essential for the first stage of establishing the TC curve of the watch), one is the *'bluerobin stopwatch'* (which can connect to specific sports heart-bands) and another one is the *'worldtime advanced stopwatch'* (which is also probably the first wristwatch that knows about the Daylight Savings Time over the entire world and changes automatically - without getting a radio signal as some other watches need for that); also there are other features like minute repeater/petite sonnerie, alarms, altimeter/barometer/thermometer, stopwatch and soon sidereal time :-!

- I am still hoping that some day based on all this experiment we will be able to do a very custom HEQ watch that will come (as standard, pre-calibarated) with under 2-3 s/year guaranteed accuracy and will be done with (much) better-quality materials/finish/WR b-)


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## Eeeb

AMAZING WORK! Kudos to all of you!


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## artec

I suppose that, in view of the variability from one example of the EZChronos to another, it would be impossible to assemble a set of software that could be made available to owners of the device who don't have a OC (ie have a Mac instead), are not computer literate enough (like me, alas) or wouldn't, for whatever reason, be able to do the necessary compensation work. 
Or do you think there is a way in which such a package could be put together, maybe with some sort of "plug-in" capacity to overcome the worst of the individual variations?
I don't know about other people, but I would guess that there might be enough who'd be interested in paying a reasonable amount for the help that such a package would afford.


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## harris498

I think this is really incredible. It's hard for me to believe that something so inexpensive could produce such accuracy. I guess it is, like you said, all about individual calibration. Nevertheless, these are important results.


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## mikeynd

Thanks for that update,and i am impressed with the results. What a cool watch


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## ronalddheld

My intent is to archive some of this content, in the future.


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## Catalin

artec said:


> I suppose that, in view of the variability from one example of the EZChronos to another, it would be impossible to assemble a set of software that could be made available to owners of the device who don't have a OC (ie have a Mac instead), are not computer literate enough (like me, alas) or wouldn't, for whatever reason, be able to do the necessary compensation work.
> Or do you think there is a way in which such a package could be put together, maybe with some sort of "plug-in" capacity to overcome the worst of the individual variations?
> I don't know about other people, but I would guess that there might be enough who'd be interested in paying a reasonable amount for the help that such a package would afford.


Sorry for the delay :roll:

Native Mac support would not be easy - actually I am a little surprised that Texas Instruments themselves have provided none. (but on the other hand the original 'target buyer' of the watch was somebody that even on a Mac would have some for of 'Boot Camp' or a VMware or similar virtual machine).

I was initially exploring the idea of implementing the entire process of "determining the individual correction" in a more hardware/automated was - unfortunately Texas Instruments never had that in mind when designing the product and as such creating at this late point the hardware for that would be VERY cost-prohibitive :-(

Providing pre-corrected watches by manual correction was also at some point in my mind - but given the amount of time it takes (and the international trips for the watches that would be required) I am afraid that the cost would become too high for such a plastic watch :roll:

On the long term the idea that remains in my mind is a project that would start with a cleaner and more 'luxurious' design (plus a LOT better materials and internal components) imagined from the start for very precise individual correction and which in the end would result in a limited edition of like 1000 watches that would be guaranteed at better than 3s/year (potentially even around 1s/y in the first 1-2 years; plus that the watches could still years later be readjusted to that kind of specification) :think: Ideally such a project would be done together with a company that already has some 'watch experience' - and since apparently somebody managed to convince Fossil to do the investment (but unfortunately IMHO on the wrong direction - more like a 'cell phone accessory' than a real watch) it remains to be seen if some other project could be started 'on the right track' b-)


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## ronalddheld

I see the trend toward more cell phone watches. Nevertheless, if the EZ successor looked and was built better, sign me up for one.


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## Catalin

*Official v2.0 firmware*

*Legal (but short-version) disclaimer - while I did test things the best I could, of course that any tests that you do are 'on your own risks' and no 'warranty' of any kind can be provided* *:roll: The files are free for personal use ONLY (I retain full copyright plus intelectual properties / patent rights) and downloading/using any of those programs should be done ONLY if you agree to this terms!*

The final v2.0 firmware is available from:

433MHz_v2_0.zip

868MHz_v2_0.zip

915MHz_v2_0.zip

and the 'companion PC programs' from:

ezc_pc_v2_0.zip

(all are dated on *August 28th 2011*).

Here is a quick map on how the final '*5 flavors*' look - remember that ALL have the HEQ/TC part inside:

- the "*Data-Logger*" - only choice that can keep a log and be used to determine the TC curve; still has bluerobin inside;

- the "*BlueRobin Base StopWatch*" - it has the basic stopwatch (and all the features in the original stopwatch firmware from Texas Instruments) + timezones and manual DST; probably the default choice if you still MUST use bluerobin with some chest-band for heart-rate;

- the "*WorldTime plus Sidereal plus MoonAge*" - it does no longer have bluerobin, but it has automatic DST and full-worldtime information (with the possibility of two timezones shown at the same time), plus minute repeater plus sidereal time plus stopwatch with split-time plus extended alarms plus altitude log and barometric alarm; probably the general 'best compromise' if you are not interested in very specific features;

- the "*Worldtime plus CountDown and Interval Timer*'" - the CountDown is a new module that I was hoping to add to the above branch, but when finally ready that one was just too big - so here we have a new *"sports and regatta-oriented" flavor which 'trades' the minute repeater and the sidereal time from above for (up to) 9 countdown timers which can be chained with one another or with the start of the advanced stopwatch and can be configured to generate sound while counting or at the very end of the interval* - see for more details the post here;

- the "*Astronomical Watch*" - that one does not have the stopwatch, bluerobin, the full worldtime (but manual timezones and DST will still be there) and all the other new features - but instead it has a number of advanced astronomical features that include *Sidereal Time*, *Equation of Time*, *Local Solar Transit Time* (actual local noon), *3 types of SunRise *and *SunSet *(on two world-wide locations that can be user-configured and which are also used for sidereal time) plus a *Moon Age* and *Moon Percentage* (that will shatter the Ulysse Nardin current accuracy claims :-d) plus eventually last new moon, next new moon and the full moon in-between! (for more details see here).


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## Catalin

*Version 3 HAQ-ezChronos firmware*

The other thread got the 'official announcement' here but I forgot to also place it here - until today when we had the DST change in Europe and the ONLY wristwatch that I have that got the change automatically was ezChronos b-) (one other radio model got to sync automatically during the night, but it was at 1 AM before the DST change itself which is at 3 AM local time here - so it was still wrong).

*Legal (but short-version) disclaimer - while I did test things the best I could, of course that any tests that you do are 'on your own risks' and no 'warranty' of any kind can be provided* *:roll: The files are free for personal use ONLY (I retain full copyright plus intelectual properties / patent rights) and downloading/using any of those programs should be done ONLY if you agree to this terms!*

Technically the version number is *3.0* for 12 MHz firmware and *3.1* for 8 MHz firmware, but since we now only use the 8 MHz version (for reasons of power consumption and avoidance of low-power reset) *the current version has an internal number of 3.1* (the minor version number is used by the PC programs to "know" what frequency the firmware has).

The 5 'firmware flavors' (astro, datalogger, bluerobin, worldtime+countdown and worldtime+sidereal) are grouped as usual for the 3 possible watch version:

433MHz_v3_1.zip

868MHz_v3_1.zip

915MHz_v3_1.zip

and the PC companion programs can be found here:

ezc_pc_v3_1.zip

If you have not used any of the v3 release candidates the overall differences from the previous v2 are split in two parts - external differences which are very-very small, and internal differences which are quite big but 'invisible'.

Other than a number of bugfixes the easy to see exernal differences are the presence of "aging compensation" in the thermocompensation part and in the INI file plus eventually a number of small differences in the timezones used by the WorldTime firmware - including now the possibility for 'user-DST' (set from Windows automatically) which changes the old *USER *timezone to be listed as *UDST*!

I will now leave my own ezChronos in timing tests for a few months to clarify the effectiveness of "age-compensation" - currently I am starting from under +1 s/y and we will see in a few months the actual evolution of that.

Have fun with the new version and let me know if there is any problem! b-)


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## edlee

*Re: Version 3 HAQ-ezChronos firmware*

Thank you, Catalin, for creating the temperature compensated watch software for the eZ430-Chronos watch. I have created a spreadsheet for calculating some of the parameters for the, "EZC3PARAM.INI", file. In calculating the seconds per year drift, should a year of 365 or 365.25 days be used? My watch calibration seems to be more accurate if I use 365 days per year.


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## Eeeb

*Re: Version 3 HAQ-ezChronos firmware*

I've stuck this thread in the stickies!! It's too good to get lost


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## ei8htohms

Hello Catalin,

This is really wonderful work. Thanks for sharing it with us!

Do you know how transferrable development for the eZ430 would be to the MetaWatch platform? I've got a project in mind that (probably) doesn't require the BT connectivity of the MetaWatch, but it would be nice to know it could be used by others if I was able to achieve any results with an eZ430.

Thanks!

ei8htohms at hotmail dot com

_john


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## drewm1980

*Re: Version 3 HAQ-ezChronos firmware*

Wow, this stuff is really cool! I read a bit about the platform, and it doesn't look like the chip is specialized to watch usage... at all. I wonder if there is another route with a simpler mcu coupled with a higher accuracy external oscillator...or maybe two or three external oscillators... Since there is nothing special about this chip, I also wonder how many smartphones could also be temperature calibrated to this extent.


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## edlee

*Re: Version 3 HAQ-ezChronos firmware*

I seem to have gotten the accuracy of my eZ430-Chronos watch down to +/-1 second per year. The clock drift fluctuates between the interval (-1, +1). The eZ430-Chronos might be the most accurate wristwatch in the world once it is calibrated as well as being one of the most affordable.

Does anyone else experience the voltage of the eZ430-Chronos watch battery increasing after exposing the watch face to light? I got a low battery warning today around 2.35v, but after I left the watch under light, the voltage gradually increased to 2.92v. The watch display flickers when it is exposed to bright light, which suggests that there might be some kind of unintended photovoltaic effect happening, with the watch face acting like a solar panel.


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## edlee

*Re: Version 3 HAQ-ezChronos firmware*

I have created an Excel spreadsheet which helps to gather the data logs from the ez430-Chronos watch and calibrate it:

http://stashbox.org/1247538/ez430-Chronos%20Watch%20Calibration.zip

The first 6 worksheets are for gathering data logs from the watch. When you retrieve the data logs from the watch using the Texas Instruments software, you can save the data logs with the *.csv extension, which can be directly opened by Excel. You can then copy the data from each *.csv file into my spreadsheet to help calibrate your watch. I used two data collection runs for each temperature range: watch in a plastic bag inside an insulated coffee mug at room temperature, watch in a plastic bag on top of the warm internet router, and watch in a thermos inside a refrigerator. Excel has a feature which allows you to add a trend line and formula to a graph to get some numbers for the, "EZC3PARAM.INI", watch parameter file.


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## edlee

*Re: Version 3 HAQ-ezChronos firmware*

I reviewed some of the documentation for the eZ430-Chronos watch. The documentation indicates that there are two quartz crystals in the eZ430-Chronos watch, a common 32768 Hz crystal and a less common 26 MHz (Megahertz) crystal. The 26 Mhz crystal is typically used for radio communication, but the documentation states that the 26 Mhz crystal can also drive the auxiliary clock (ACLK) line, which can drive the watchdog timer. The watchdog timer can be used as a counter and trigger a periodic hardware interrupt. The 26 Mhz crystal can be left running even when the radio communications gear is off. At full speed, the 26 Mhz crystal is rated as using about 100 times more energy than the 32768 Hz crystal. This seems to open up the possibility of periodically waking up the 26Mhz crystal, perhaps every hour or so, waiting a second or two for the frequency to stabilize, and using the 26Mhz crystal to calibrate the 32768 Hz crystal. The 26 Mhz crystal can also be throttled down in coarse increments to save energy. Perhaps the 26 Mhz crystal can be used as the main time keeper. It's an interesting possibility.

Parts of Catalin's software concerning radio communication updates of the firmware and the pressure sensor will not function on the newest version of the eZ430-Chronos development platform. The pressure sensor and radio frequency hardware have changed. The radio communications board on the USB dongle is now white instead of black. Here's a Google groups discussion link:

https://groups.google.com/forum/?_e...mU#!topic/ti-chronos-development-/brVwaCNqNmU

Perhaps the original ez430-Chronos watch will become a collector's item for its rarity and accuracy with Catalin's software. The eZ430-Chronos development platforms were never mass-manufactured, and the amount of time and determination required to calibrate the watch will ensure that not many people will possess calibrated versions of the watch.


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## edlee

*Re: Version 3 HAQ-ezChronos firmware*

Mouser Electronics apparently still has the original eZ430-Chronos watches in stock. I just bought two more watches from them. These have the black radio USB serial ports instead of the newer white ones. They had about 150 left when I last checked. This may be of interest to people who want an affordable and potentially very high accuracy quartz watch for about $62. Their web site is:

chronos | Mouser Electronics, Inc.


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## edlee

*Re: Version 3 HAQ-ezChronos firmware*

I recently realized that the calculation of T2_a5 in my Excel spreadsheet is too high by a multiple of 10. The internal watch representation of the incorrect T2_a5 value within my first eZ430-Chronos watch just happened to be close to the correct value.


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## edlee

*Re: Version 3 HAQ-ezChronos firmware*

My first eZ430-Chronos watch recently lost calibration all of a sudden and began to be slow by several minutes over three days. I recalibrated the watch with a room temperature, high temperature, and freezer temperature data logging cycle. The watch seems to be good now. The nice thing about these watches is that you can recalibrate them if the quartz crystal ages or if the temperature sensors age.


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## lswatches

*Re: Version 3 HAQ-ezChronos firmware*



edlee said:


> My first eZ430-Chronos watch recently lost calibration all of a sudden and began to be slow by several minutes over three days. I recalibrated the watch with a room temperature, high temperature, and freezer temperature data logging cycle. The watch seems to be good now. The nice thing about these watches is that you can recalibrate them if the quartz crystal ages or if the temperature sensors age.


I find it so amazing how software can improve almost everything in our lives! Way to go guys.


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## ronalddheld

*Re: Version 3 HAQ-ezChronos firmware*

anyone up for analysing some data for me?


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## edlee

I recently gave ronalddheld a spreadsheet that I had used to calibrate my eZ430 Chronos watch. I have forgotten a lot of the calibration procedure, since it has been several years since I last calibrated a watch, but I had last managed to get one of my eZ430 Chronos watches accurate to less than 5 SPY either on or off the wrist.

My eZ430 Chronos watch strap broke. The eZ430 Chronos uses an integrated resin strap without lugs. I need something like a custom 3D printed plastic case that can accept the original steel bottom piece which is held in place with four screws. I could reuse the original watch's side buttons. I would like to insert a new sapphire crystal face and use a new NATO band either with metal lugs or through holes in the plastic. Sapphire crystals can be affordably purchased on eBay. I tried using a Meta Watch MW4001 case, which contained a variation of the ez430 Chronos, but the innards of the eZ430 Chronos did not quite fit in the Meta Watch case. The Meta Watch case was wider on the sides and not long enough. It looks like I could grind off part of the air pressure sensor to make the guts of the eZ430 Chronos fit in the Meta Watch case, but I would rather not damage the movement.

Whatever happened to Catalin?


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## Disconnected

This is absolutely amazing, would really love an update on this project.


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## ronalddheld

The project is long over,as the OP has not posted here in many years.


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