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