this post was submitted on 17 Mar 2024
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Home Automation

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Discussion about general home automation ideas and projects, home automation protocols like Z-wave, Zigbee, Matter, etc, and home automation software and hubs like HomeSeer, Home Assistant, OpenHAB, Homey.

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We've heard about multi-sensor ESPHome projects, like a presence sensor using PIR and mmWave Radar, also installing lux meters, temperature/humidity, etc. The GPIO pins are there, so why not?

I'm curious to hear if anyone has tried running a sort of multi-zone system of different sensors. That is, rather than colocate all of the sensor elements in the same housing, mount the sensors in different locations or rooms, connected to the project board over a longer cable run, like maybe old, disused CAT5, CAT3 or CAT1?

I had an idea where I might make a network of temp/humidity sensors. I have a discarded spool of CAT3 UTP cable. It'd be easy for me to pick a central spot in my home for a hub, and run CAT3 to several rooms through a convenient crawlspace I wonder if i could extend VCC, GND and digital I/O pins to sensors in those other rooms over those hypothetical CAT3 runs? Maybe use a level shifter and common 5V & GND rails off a power cube? I can see analog sensors being an issue because you'd need to figure the voltage drop over the distance, maybe.

It could even use RJ11 or RJ45 terminals in printed housings at each end to keep things neat.

Has anyone tried this? How'd it work out?

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[โ€“] [email protected] 4 points 7 months ago

My current project repurposed some CAT3 running to an external sensor, but you may have to double check how that affects your signals. I've had problems with voltage drop before (if that changes how your sensors communicate).

CAT5 for networking gets away with long runs by doing fancy signal processing on wire pairs that our projects don't do, so expect lower tolerances.

[โ€“] [email protected] 2 points 7 months ago* (last edited 7 months ago)

ESP boards are so cheap that in my opinion this doesn't make a whole lot of sense - it's probably going to be more expensive than distributing ESPs around due to the wiring, and I guess I'd argue the distributed nature of HA/ESPHome is one of the best things about it, versus centralized alarm panels, for example, that used to be common decades ago, bringing all wiring back to a single location. Optimizing for unused GPIO pins isn't really something that bothers me, personally. What I like about my ESP projects is just the opposite - that I can sprinkle them around the house close to the things they measure and control.

I don't mean to be super negative - of course you should do it however you want to, but that's my opinion - for what it's worth (i.e. nothing).