Say, Hubitat developers, since offnet automation is one of Elevation's key selling points why don't you integrate an onboard clock? Seriously, is there no space for a button cell battery & a CMOS clock? Not enough ROI in that? Is expecting customers on the low profit side of the digital divide to run their own NTP server any way to attract sales? It is not. Even X10 controllers keep time during power failures!
Firstly.. Welcome to the community..
The focus is on local processing not quite the same as off-net... As in internet and or cloud outages won’t stop your automations of non-cloud devices...
And without ntp how would you handle clock drift, and internet updates of local sunrise and sunset times? Not saying RTC w/ battery wouldn’t be useful...
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It makes sense but my experience has been, every device that had a battery powered clock (or CMOS memory) sooner or later it's been a problem.
I think the functional requirement for a local time source that can withstand a power outage is a good one especially considering the "local" aspect of the marketing of Hubitat.
Thanks for the speedy reply!
I'm not looking for precision. Inaccuracies of +/- 10 minutes would still keep my wife's house plants healthy & make our home look occupied when it isn't. An unattended power failure/restoration shouldn't skew automation by hours. I haven't run simulations yet so please enlighten me for this hypothetical situation. Assume I have lights on z-wave outlets scheduled to illuminate 8AM - 6PM. No internet b/c we're stuck with cellular data caps. No UPS. Power fails at 4PM, restored at 9PM. What time will Elevation assume without NTP? What condition should I expect from a GE 14288 receptacle?
There has been much discussion in this forum about suitable UPS units in light of the need to protect the hub from crashing as well as the time keeping issue. It doesn't take much power to keep the hub running, short of a "real" solution to your request, a relatively inexpensive UPS could keep your Hub (and its clock) running for quite a while I would think.
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A couple of us here use the earlier version of the talentcell mentioned in this ups thread.
Worked great yesterday (yet again) during multiple southern storm outages.
Looks like the new version is here.
https://www.amazon.com/TalentCell-Rechargeable-Amplifier-Multi-led-Indicator/dp/B00MHNQIR2
Yes it would be nice if the hub had a realtime clock. But it doesn't, and no amount of wishing will change that.
Get a ups.
Maybe a future version will have a RTC. Who knows?
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Thanks rcjordan & Mr. Miller. I have UPS options on hand but the USB option is very appealing for avoiding conversion losses between UPS & wall wart. Imagine the HE's runtime with a large, deep-cycle battery & a thumb-sized USB power adapter. Necessity is the mother of improvisation & I've sired quite a brood with her.
You could also use an rpi with a GPS receiver to roll your own ntp server. No internet required.
We are certainly cognizant of the issue, but with a very tiny percentage of customers wanting off-net use of the hub this hasn't risen on our list. We will continue to look at possible solutions. There is a potential clock solution using an external GPS stick.
There are very low cost battery UPS solutions -- I'm using one that's good for several hours.
This is not how it works. Sunrise and sunset are calculated using software astronomical clock based on lat/long.
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Nice … I was making an assumption.. My assumption was wrong...
I'll throw my 2 cents on this and say that it would be nice to have as well. However, at the same time, I doubt it would have any usefulness in an environment without internet. They simply do not have the accuracy and even the best ones can drift by a few minutes within a couple weeks, and that's assuming they're used in a temperature controlled environment. If not, then accuracy gets worse as subtle temperature shifts affect the frequency at which the crystal oscillator resonates in the clock module.
A clock source with a temperature-controlled oscillator (aka crystal oven) or external GPS time source are the only ways to maintain a stable clock lock over an extended period of time.
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A GPS on a USB dongle would be a pretty good solution assuming you can get a strong enough signal. With a USB extension most people would probably be able to place it where it would get a good enough signal.
Anything that requires another device on the network, such as a pi, then starts you down the slippery slope of needing to keep your ethernet switch or WiFi Access Point powered as well. This leads to a whole house generator (ask me how I know).
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Heh!
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