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Solar powered LED watch

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cobra007

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Solar powered LED watch

Post09 Dec 2013, 22:55

Hi Guys,

Since completing the Kopriso Mi Esposita solar powered LED watch, I was wondering if perhaps this is the first solar powered LED watch after Roger Riehl designed his Synchronar back in the early 1970's? There are many solar powered LCD watches around but as far as I know, no other LED watches. A google search didn't lead me to other solar powered LED watches either. It is notoriously difficult to design a solar powered LED watch due to the fact that LEDs consume so much more energy than LCDs. This one is still slightly more energy friendly than my solar powered nixie watch (battery consumption is about 30% less than the nixie display).

Unlike the synchronar, the solar panels I have used are designed for modern light sources, including fluorescent and LED. The watch can be charged using a "Cold White" light source. Also, the used battery (Lipo), has no memory effect so it won't need a periodic complete discharge. If the watch is not used, 100lux ambient light is enough to keep the battery charged.

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Cheers,
Michel
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charger105

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Re: Solar powered LED watch

Post10 Dec 2013, 04:38

Hi Michel.
Uranus produced a solar powered/assisted LED watch, and a solar version of their LED calculator watch:

http://www.digitalwatchlibrary.com/DWL/ ... watch-1972
http://www.ledwatches.net/photo-pages/uranus2.htm

Both extremely rare though.
BTW, really nice work with your new watch designs. I like the Nixie one best.
Rgds,
Andrew.
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cobra007

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Re: Solar powered LED watch

Post10 Dec 2013, 06:21

charger105 wrote:Hi Michel.
Uranus produced a solar powered/assisted LED watch, and a solar version of their LED calculator watch:

http://www.digitalwatchlibrary.com/DWL/ ... watch-1972
http://www.ledwatches.net/photo-pages/uranus2.htm

Both extremely rare though.
BTW, really nice work with your new watch designs. I like the Nixie one best.
Rgds,
Andrew.


Thanks for that Andrew!

That's right, the nixie display is of course nicer although this looks very cool as well and will definitely attract some attention. The idea was to bring the prices a bit down that I need to pay for cases and sapphire crystals by selling a couple of LED watches along the nixie watches.

Need to put one for sale on ebay to see if that plan will work out :-).

Regards,
Michel
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ronaldheld

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Re: Solar powered LED watch

Post10 Dec 2013, 14:41

Would you consider designing that for 2 LED digitals?
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cobra007

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Re: Solar powered LED watch

Post10 Dec 2013, 22:46

ronaldheld wrote:Would you consider designing that for 2 LED digitals?


The whole setup of the Mi Esposita design is based on a single digit display. So, although it would probably be possible to fit 2 LED digits, it would be too much work to actually make it work.

I have been wearing this watch now for several months and there really is no draw back due to the single digit. In 12 hour mode, there are only 5 hours that require 2 digits (10,11 (am) and 12,10,11 (pm)). In theory also 12am (or midnight) but I display that as "0", it's probably the only watch in the world that displays "0" at midnight in 12 hour mode :-). Also, days of the week are just 1 digit (day 1 - day 7); battery reserve just 1 digit (0 - 9); the trigger counter (0,000 - 99,999) is hard to display on a dual digit display (left hand digit can only show 0 - 5; not 0 - 9) but very easy on a single digit display.

A dual digit display requires twice the power to achieve the same brightness as a single digit. This is however not possible for the nixie tube display. The battery can "only" supply 200mA and a dual digit display would then require a 400mA battery current. My dual tube nixie watch is half the brightness of the single tube. This is not really a problem indoors but when you go outdoors it is so convenient to have that extra super bright display.

Another interesting discovery is that a single digit display also saves almost 50% battery power. You may think "yes, of course" but it is actually not that simple. Normally on a dual digit watch, the hours will turn on for 0.6 seconds and the minutes also for 0.6 seconds, this results in a convenient time reading. Now, like I said, to keep the dual and single display at the same brightness level, the dual display draws say 100mA and the single display 50mA. This means that if the time was displayed on the single tube display as 0.6sec + 0.6sec for hours and 0.6sec + 0.6sec for minutes; the actual power consumption would be identical to the dual tube watch as they draw half the current but for twice as long. The interesting discovery is that to conveniently read the time on a single tube, each digit should only be on for 0.4sec. Since most of the time only 3 digits need to be displayed (1 for hours, 2 for minutes), the display will be on for 0.4sec (hours) + 0.4sec + 0.4sec (minutes). Total time 1.2sec, exactly the same as the dual tube but at half the battery current! For a solar powered watch, this is of course a huge benefit! That is, for most of the time except for the hours 10, 11, 12, 10, 11, but that would only add another 0.4sec so not all that dramatic.

Wish this explains my choice for single digit :-)

Regards,
Michel
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charger105

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Re: Solar powered LED watch

Post11 Dec 2013, 08:50

cobra007 wrote:Hi Guys,

Since completing the Kopriso Mi Esposita solar powered LED watch, I was wondering if perhaps this is the first solar powered LED watch after Roger Riehl designed his Synchronar back in the early 1970's? There are many solar powered LCD watches around but as far as I know, no other LED watches.

Cheers,
Michel


...........and who could forget the Alfatronic:
http://www.crazywatches.pl/nepro-alfatr ... s-led-1976

I think Bucko's got one. Always wanted one of these :mrgreen:
Rgds.
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cobra007

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Re: Solar powered LED watch

Post11 Dec 2013, 09:16

charger105 wrote:
cobra007 wrote:Hi Guys,

Since completing the Kopriso Mi Esposita solar powered LED watch, I was wondering if perhaps this is the first solar powered LED watch after Roger Riehl designed his Synchronar back in the early 1970's? There are many solar powered LCD watches around but as far as I know, no other LED watches.

Cheers,
Michel


...........and who could forget the Alfatronic:
http://www.crazywatches.pl/nepro-alfatr ... s-led-1976

I think Bucko's got one. Always wanted one of these :mrgreen:
Rgds.


Yes, I saw it this afternoon on this web page:
http://watchismo.blogspot.com.au/2007/01/top-10-vintage-solar-powered-watches.html

It's a list of 10 vintage solar powered watches. 3 of them are LED watches, including the ones you mentioned. Was the Alfatronic just as a popular was as the Synchronar?

Regards,
Michel

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