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Cake day: March 2nd, 2024

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  • I’ve got two of the Screek 2A sensors and think they’re good. Mmwave technology isn’t a magic bullet that automatically works every time, like all radio tech there are some limitations.

    I use one to turn on a light in a hallway and the other to detect when someone approaches the front door and issue an alert via ntfy.sh. Once in a while it misses some motion, so I’d probably not recommend it if you were building a human life kind of scenario, but they’re fine for me.

    More importantly, they’re well supported by HA/ESPHome, open source, inexpensive and compact.





  • how do you typically notice the filter needs to be changed now? does it:

    • draw more power than usual? wattage sensor
    • give some alert like a “change filter” light? esp32
    • need changing after a certain time/usage amount? power consumption sensor
    • need changing every X days? you might just need a calendar alert

    of course the mega nerd approach would be to put a particulate sensor in the duct like a PMS7003 that measures PM10 particles like dust, strap on an esp32 and set some alerts using your favourite monitoring tool.
















  • thr0w4w4y2@sh.itjust.workstohomeassistant@lemmy.worldHome Wiring
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    8 months ago

    I’m using PoE Extractors to run some regular 12vdc stuff using existing ethernet cabling.

    A couple of points to note:

    • network switches won’t turn on power by default unless the receiving device asks for it using the right protocols, so you need to inject the power using the corresponding PoE injector at the other end of the cable. you can’t just snip the end off a RJ45 and wire it into things.
    • Cat cable won’t take high currents, be sure to stick within the allowed range for the cable or it will melt and maybe bust your device
    • there is a voltage drop over distance, be sure to calculate if you need to change your transformer as 12vdc could become 9 or lower by the time it gets to your device
    • there are some really poor quality PoE injectors/extractors.
    • running mains cable and having a transformer nearer the device might be simpler and cheaper in the long run.