On Mon, 16 May 2016 15:45:14 -0700, you wrote: >You do not need anything connected to the beaglebone for any reason. The >beaglebone has an on die ADC that can detect if the AC mains is powered or >not. In which case, after a preset time period the Beaglebone could shut >its self down.
True enough. The prevailing wisdom was going with an external device having all the smarts about power failure, while the BBB was being held up by batteries. The requirement that you propose is that the BBB have, somewhere, access to power long enough to do a graceful shutdown. How this is done is left as an exercise for the student. > >Meanwhile, an external "device" can just switch off the input 5V to the >beaglebone after a preset amount of time. Then once you have AC power back, >the "Device" simply turns the 5V back on. Yep, and with the same requirements of powering from either a battery, a supercapacitor, or something more exotic. The bottom line seems to be that the BBB was not designed for this kind of situation or application, and making it fit this requires additional resources of some sort. Now the question comes down to cost, utility, percentage of applications needing this, elegance of design, and whether or not the hardware platform can cooperate in this or whether or not it simply lives in its own world. Harvey > >On Mon, May 16, 2016 at 3:09 PM, Harvey White <[email protected]> >wrote: > >> On Mon, 16 May 2016 11:35:54 -0700 (PDT), you wrote: >> >> >Looks like nut been ported to Debian for the BBB. >> > >> >It and a smart UPS might be the easiest solution. >> > >> >I'm thinking along these lines, but haven't done anything with it yet. >> The >> >nut client getting a signal over the network from my desktop is kind of >> >what I'm thinking. I've my BBW IOT app, router, and ISP interface on >> >a separate UPS that I want running as long as the battery lasts, but a >> >controlled shutdown of the BBW is something I'd like to add eventually. >> > >> >The "shutdown if the power outage lasts longer than X" is pretty easy, >> >robust automatic start-up when the power returns might require a smarter >> >than the average UPS. >> >> I'd say that you want one that does automatic battery tests as well. >> The one that I knew of at one time was a sine wave inverter. >> >> To summarize the types of inverters, there are two schemes. >> >> 1) keep a battery charged at all times. When power fails, detect the >> loss of AC at the output. Start the inverter and switch that power to >> the output of the inverter. What happens is that power drops out for >> the output with a power failure, and your equipment is supposed to >> stay "up" for a certain amount of time (that the UPS takes to switch >> on). Then the UPS takes up the load and life is good. >> >> 2) keep a battery charged at all times. Power the inverter from the >> battery at all times. When the power fails, the battery charger >> simply shuts down. >> >> The second one is the one I'd think you'd want to get. >> >> An opto isolator, driven by an AC bridge (or an AC style optoisolator) >> would give you a power failure indication within a half cycle. >> >> Harvey >> >> >> > >> >I'd be interested in success stories, but my experience with brand name >> >(APC) and off-brand UPS with desktop system is while they are better than >> >nothing, they aren't good at reporting battery issues and ultimately I >> end >> >up with a power failure and "pull the plug" type shutdown because the UPS >> >batteries can't support the switch over. We get a lot of 0.5 - 15 minute >> >power failures from thunderstorms here, so I'm sure the USP has saved me, >> >but they are not foolproof. >> > >> > >> >Ultimately I'm trying to sell the wife on a "whole house" natural gas >> >powered backup system so that a dumb UPS or battery with only a few >> minutes >> >run time to let the generator come on and switch over would be needed. >> >She was excited about it after Hurricane Ike, but now that its been ~eight >> >years, selective memory has her thinking we don't need it. >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/apfkjbtvsk9h94q0qvfpke40ofhbc7c22h%404ax.com >> . >> For more options, visit https://groups.google.com/d/optout. >> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/silkjbt8elht0qlo1536jduujmhaekcobc%404ax.com. For more options, visit https://groups.google.com/d/optout.
