Looking for input.
I'm going to outfit small private school I work at with temperature sensors. I do not find wireless (zigbee, wifi, etc.) sensors reliable. A couple of weeks ago, I realized that our school has wired cables going from a server room, to most of the rooms in the building. Out of around 50 ethernet ports, we only utilize 6 (wifi APs + printer). A principle sketch of our layot is shown in image:
So, I have discovered mainly two options:
- 1-wire sensors with RJ45 connection, 1-2 hubs and a controller
- ESP32 w/PoE
The 1-wire option
I've found a company called UniPi, which sells 1-wire sensors with RJ45 plugs, hubs and controllers based on Raspberry Pi. There are probably similar options available. This would mean I would have to buy sensors like this On wall temperature sensor with a RJ45 to 3 pin 1-wire cable. I would have two hubs allowing for 13 sensor points. I would also need a controller as well as a Raspberry Pi.
- Would use of the hub with the long stretches of lan cable mean that the travel length of the signals would be too far, or is it in parallell?
- How should I set up a NodeRed in such a system? Where do I put it? I want data logged at intervals of 1 to 5 minutes, and I need a way for this data to be displayed in interactive graphs, readily available online. I would also like to set up alarms triggered by certain temperature events.
Here, I would need an affordable switch w/PoE. I would also need "safe" ESP32s, which wouldn't damage any of our other lan infrastructure (switch, UDM-Pro, APs, ...).
- How would I solve this in the most elegant manner? Would each ESP32 be an autonomous device, addressable over the internet - i.e. would each ESP32-device be accessible through an online iteration of NodeRED running on AWS? Or do I need a on-premises controller running NodeRED?
- Which ESP32 PoE devices should I go with?
Would love your suggestions or advice on this. Especially input on reliability, affordability, design and implementation time. Would also like suggestions for "complete" solutions for solving this, how it could be set up.
- edited because I forgot to link a controller - *