I want to use an ultrasonic sensor to monitor levels in a heating oil tank
1. This tank will be remote thus should be battery powered. As such it should sleep as much as it can, to save battery power.
2. All of my sensors/controls so far are simply on ESP's in station mode, acting as servers, accessable via local network with a cell phone. I'd like to follow that concept.
I'm thinking that (obviously) the sleeping ESP will not be easily accessed via wifi so....
My thoughts at this point are to have the sensor driven ESP wake and send the calculated distance from "tank bottom" to a continuously powered unit (ESP, Rpie, whatever) which can be accessed by cell phone. I've fooled with MQTT only enough to know I can get data to a broker (on a Raspberry pi), but can I access the broker as a server to place the information on an accessing browser from my android phone.
In other words can the unit used as a broker be a web server to relay information to a browser as well?
Or am I overcomplicating the issue? Thanks for any advice.