InterSystems Caché’s native datetime format is days-since-12/31/1840 + comma + seconds-since-midnight. I call this $H format because it’s the format the the $H (short for $horolog) Caché system variable returns.
As an example,
would translate to
in $H format.
What I Want
I want a $H clock.
- The clock should display the $H time in big LCD numbers, updated once per second.
- I’m thinking the clock would be about 3″ high by 8″ wide.
- I don’t want it to be attached to the computer or powered by the computer. I can already display the $H time on the computer. If the $H clock gets its time or power any way from a PC, the whole coolness factor for this is gone.
- Battery powered probably, but could be electric plug-in or solar powered, I don’t care so much as long as it’s not powered by a PC (see #3).
- If I build this myself, I’m willing to spend up to about $50 on materials because it will be so fun to attempt, but if someone else beats me to it I’m only willing to spend about $15 to buy their version.
- I have to be able to set the time somehow, preferably not by typing in a raw $H number (which I would have to look up on the computer -> detrimental to coolness factor -> see #3).
- I don’t care if it supports a 6-digit year value (that would be needed starting on 10/16/2114). In fact, I’d probably rather it didn’t leave room for more than a 1 in the sixth column, as the extra space could make the display proportions look odd, detracting from the coolness factor. (The coolness factor is very important to me. : )
I expect there might need to be an IC chip to compute the $H datetime display from the current date and time. Here’s some Python code that does the job, as an example:
# $horolog-style date/time. from datetime import date,datetime dateh = date.today() - date(1840,12,31) now = datetime.now().time() timeh = (now.hour * 60 + now.minute) * 60 + now.second print str(dateh.days)+','+str(timeh) def FromHorologFormat(horolog): parts = horolog.split(',') dateh = date(1840,12,13) + parts timeh = parts timeDec = timeh hours = timeDec / 60 def ToHorologFormat(dateParam, timeParam): dateh = dateParam - date(1840,12,31) timeh = (timeParam.hour * 60 + timeParam.minute) * 60 + timeParam.second print str(dateh.days)+','+str(timeh) def currentHorolog(): dateh = date.today() - date(1840,12,31) now = datetime.now().time() timeh = (now.hour * 60 + now.minute) * 60 + now.second print str(dateh.days)+','+str(timeh)
For an IC chip it might need to be done in C, but the Python could serve as pseudocode…