Hi Trevor, My first thought would be to use a UPS that provides a Power HID device over USB. It's safe and *should* be simple. I haven't messed with it but there is Linux software for monitoring and reporting UPS status.
The "ghetto" way would be to use an opto-isolated zero-crossing type circuit to pull down a GPIO. The signal will briefly pop back up near the zero crossings but at least you'll know that AC is present. The usual disclaimer on this method: 120VAC can kill. -Ron On Thursday, August 16, 2018 at 2:57:55 PM UTC-5, Trevor Morris wrote: > > > Looking for suggestions... > > I have an IOT device that has a BBB with a power cape powered by a 5vdc > psu hooked up to a switch and a 4g modem that are powered by a 24vdc psu > all powered off of an incoming 120vac line. > > The power cape is setup to gracefully shut down the BBB if the power is > off for more than 30 seconds coming off of the 5vdc psu. > > I'am adding an APC UPS in front of both of the smaller PSU's so that I can > keep the entire unit connected to the network on powerloss. > > What I'am not sure how to approach is monitoring supply current so that > the beagle knows when Line voltage is no longer being supplied. Some of my > ideas have included using one of the random sensors I see floating around > or using a NC relay and holding it open with power. I main want to be able > to send an sms to myself if the power switches to the UPS and I'am > currently less concerned about monitoring the status of the UPS or anything > like that (although that would be cool). More important that the device > tells me when it goes off mains power and when it goes back on mains power > so I can decide weather or not I need to go attend to it. > > Has anyone tried to do anything like this? Any suggestions for a simple > way to monitor when the current drops to zero with the gpio pins? Seems > like I should be able to do this some real ghetto, yet reliable way.... > > Thanks > -- 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/7757d8cb-f6b4-490d-9960-77228d9aa02a%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
