I also monitor the voltage (9v transformer and voltage divider) so I am getting current & voltage, and also time, so I can monitor KWh not just KW.

I also monitor the voltage (9v transformer and voltage divider) so I am getting current & voltage, and also time, so I can monitor KWh not just KW.

I use main line snap on current sensors for whole house monitoring, and snap on or hall effect sensors for specific device monitoring when necessary. I use current shunts for high current, low voltage dc monitoring like battery backup or off grid solar power systems.

That's what I have to figure out how to do. I was thinking of using MQTT, but pushing the commands back to the home system is kicking my butt. I can have the home subscribe to the MQTT broker, but how often should I check? If the user says "open garage door" he wants it done now, not 5 minutes from now. I can't assume I can open a IGP / UPnP port on his router.

Is there a way to do this without a cloud server? Can the cell phone app "call home" without router configuration? Maybe pair the cell phone app with the controller initially, then a VPN or some such is maintained between them. Please forgive my ignorance. I have designed networked sensors that insert data into a mysql database, and graph the results using php and json, but sending info back to the home is new for me. I am a network engineer, but trying to prevent the user from having to be.

My understanding so far is like this: If a controller sends an update / heartbeat to a IOT server, instructions from the IOT server can be passed back through that session? So the user, talking to the IOT server with his cell phone, has the ability to tell the home controller to do something, without the user having to configure NAT/PAT on the router?

I've seen several cloud based IOT hubs that claim to require no port forwarding or port triggering configuration on the home's default router. How can I deploy 2 way communication (oh, garage door is open? click button on cell phone app to close it.) without the user needing a course in router configuration?