Hi all,

I’m looking for a reliable smart plug with current/energy monitoring that meets these requirements:

  • Ideally <1s time resolution (I need fast updates, not just averaged every few seconds.)
  • Wi‑Fi connectivity preferred, with MQTT client support out of the box (similar to how Shelly devices can publish to a local MQTT server when the load current changes. I’d rather not have to poll a device’s HTTP endpoint a few times per second.)
  • Provisioning/config: Bluetooth for setup would be a big bonus (I think the Shelly Plug S Gen3 can do this, too.)
  • Reliability/manufacturer: Needs to be from a well‑supported brand or at least something that’s proven stable and not a “cheap no‑name” option.

I’ve been testing a few devices already. Most average power consumption over longer periods, while e.g. newer Shelly devices come frustratingly close to being exactly what I need.

Does anything on the market provide sub‑second resolution for current measurement? Most consumer plugs I’ve tried either average readings or only publish once every few seconds, which isn’t quite enough for my use case (measuring transient behavior and categorising operating modes of certain appliances).

Has anyone come across a plug that ticks these boxes? Or maybe a hidden configuration with Shelly devices that I’ve missed?

Thanks a lot for any help!

Edit: What I’m actually looking for is a fast response time to significant changes in power consumption (by more than a set amount or a percentage), so a high sample rate within the plug. A constant delay until the message is sent out wouldn’t be a problem at all.

  • tofubl@discuss.tchncs.deOPEnglish
    2·
    27 days ago

    Thanks, I’ll look at that device.

    It’s actually not so much the fast interval that I’m looking for, but fast response to changes in power consumption. In fact, I’d prefer not to be flooded by multiple messages per second but to only receive them on significant change (where “significant” would have to be configurable.)

    The Shelly AZ I have been thoroughly testing sends out MQTT messages when power consumption changes, but has a delay between 1.5 and 2.5s, sometimes up to 5s. If this were either faster or at least consistently delayed by the same time, I could use it.

    Reading up on Tasmota I’ve seen the PowerDelta configuration value which I think is what I am looking for…

    • wildbus8979@sh.itjust.worksEnglish
      5·
      27 days ago

      Since you have very specific requirements I would read up some more to make sure it fits the bill before you purchase one.

      You should also know that for either ESPHome or Tasmota you’ll require a flasher (usb to TTL serial device) and some soldering skills (for the S31 there’s also a 3d printable jig that exists)

      • tofubl@discuss.tchncs.deOPEnglish
        3·
        27 days ago

        Sadly, manual reflash is sort of a non-starter for my specific situation, but I have found devices that ship with Tasmota and ESPHome preflashed. I ordered a few to test.

    • onslaught545@lemmy.zipEnglish
      1·
      27 days ago

      You’d be better off using helpers to do that, although I believe Esphome can do it using sensor filters.

      • tofubl@discuss.tchncs.deOPEnglish
        2·
        27 days ago

        You mean fire out data as fast as possible and take care of processing on the server? I’d be okay with that if necessary, but so far I haven’t found one that seems to even measure the power consumption fast enough. They all average over some time frame between a few seconds and even minutes. This is of course fine for regular home appliances, but not fast enough for the problem I’m trying to solve.