Hi Folks,
I am trying to build a system that can alert me to a loss of AC power to an installation.
I have looked at the Watteco “Intens’o” unit but this seems to be unable to do the job.
It seems like the simplest thing would be a node that plugs into the AC and fires off a heartbeat every n minutes. I could build this but I would rather not. However this very simple functionality doesn’t seem to be found on any manufacturers site I have seen thus far.
Has anyone found a product like this?
What I’ve done in the past to build this is to use a Dragino water leak sensor and replace the sensor with a simple circuit that is mains powered and closes the loop when no power is applied. Can be as simple as a wall wart (power brick whatever you want to call it), diode, and relay with switching contact. Use the power to make sure the relay is engaged but the circuit is open when mains is available and when power fails the relay disengages to connect the two wires from the LoRaWAN unit.
It seems they have a nice unit to use these days. I ‘had to make do’ with the LWL01 years ago.
Advantage, you only get one heartbeat a day until power fails, then there are more frequent notifications.
Ideally you want a device that has enough power reserve (honking great capacitor, preferably a very small LiPo) - like the Adafruit Feather M0 with RFM95 (it has the LiPo charge circuit on it already).
Then power it using a phone charger, it monitors the input voltage, if it goes, it has the battery to send out (a few) alerts. This way you don’t need to detect the absence of a message which gets to be a PitA.
As it won’t need to sleep, it’s a quick win for LMIC-node for firmware.
Thanks Jac,
I have ordered two of the Dragino units…hopefully they will do the trick. Seems like a gap in the market if something this simple doesn’t have an off the shelf product. Don’t you think @descartes?
if your gateway are reliant on been online of the power you are measuring and it goes down
just remember if your node were sending via this gateway to the lns, it will be on sf7
will this sf7 message reach the next closest gateway