Notify when an appliance finishes its cycle, from its power draw

What you need

• An energy-monitoring smart plug rated for the appliance you are plugging in. A washer, dryer, or dishwasher draws far more than a lamp, so the plug has to be specced for a high-power load, not just any spare one from a drawer.
• A platform that can trigger on a numeric power reading and hold a condition over time. Reading the wattage is the easy part. The automation lives or dies on being able to say "stayed below this for this long," which is why Home Assistant and Homey are the natural homes for it.

How it works

A running appliance pulls real power. A washer heats water and spins a drum, a dishwasher runs a pump and an element, and all of it shows up as a clear rise on the plug. When the cycle ends, the draw falls back to the trickle the electronics sip on standby. So the obvious rule writes itself: power was high, now it is low, so it must be done.

That rule fires early, and the reason is the whole point of this page. Appliances go quiet in the middle of a cycle. A washer sits near idle during a soak or between fill and spin, and that dip reads exactly like the end of the cycle to a simple threshold. Trigger on the first dip and you get a cheerful "laundry done" while the machine is only halfway through.

The fix is to make the automation wait out the quiet. Rather than firing the instant power drops, it requires the draw to stay below your threshold for a stretch of time longer than the appliance's longest pause.

A single power reading can only tell you an appliance is quiet right now, never that it is finished. Completion is a low draw that lasts. Set the wait longer than the machine's deepest mid-cycle pause and the false alarms disappear.

If you would rather not read watts at all, a vibration sensor stuck to the machine follows the same shape, going still at the end. It needs the same wait-it-out rule, for the same reason. That is a separate build from the automation below, which reads watts.

Finding your two numbers

You cannot copy these off another setup; you watch them once on yours. Run a full cycle with the plug's live power readout open. The first number is the standby draw after the cycle genuinely ends: set your threshold just above it, so a finished machine reads as off. You will see the appliance dip close to that same level during its mid-cycle pauses, and that is exactly why the threshold alone cannot call the finish. The second number does that job: the longest of those pauses. Set your wait comfortably longer than it.

Which platforms can hold the wait

Everything here rests on one capability: trigger on a numeric power value, then require it to persist. Home Assistant does that directly, with a numeric trigger that carries its own duration. Homey can hold the same sustained wait. The cloud routine platforms are thinner. SmartThings can still express the sustained condition, through its Rules API rather than a basic routine. Alexa, Google Home, and Apple Home cannot: their automation editors expose no wattage trigger at all, so there is nothing to hang a wait on.

Watch out for

• The plug carries the entire appliance, so its rating matters. A washer's heater or a dryer's element can pull more than a plug built for lamps and chargers will safely pass, and an underrated plug is a fire risk.
• This pattern suits appliances with a clear start and a clear stop.
• There is nothing to reset between runs.
• A plug that stops reporting can fake a finish, and it can go quiet for all sorts of reasons: a dropped connection, an integration reloading, a firmware update. The automation treats that silence as the power no longer being low, which re-arms it. The standby trickle it sees when it comes back then reads as a fresh drop, so you get a done alert for a cycle that never ran. If yours goes quiet often, have the rule watch for the machine starting first. Only then does it wait for the drop. A finish can then only follow a start it actually saw.
• It only tells you the cycle ended. Whether you go and move the laundry is still on you.

alias: Notify when the washing machine finishes
description: >-
  Alerts you once the washing machine's power draw, measured by an
  energy-monitoring smart plug, has stayed below a low threshold long enough to
  mean the cycle has truly ended rather than paused mid-cycle. Swap in your own
  power sensor and notify target. It trusts the drop on its own, so it does not cover
  a plug that stops reporting.
mode: single
triggers:
  - trigger: numeric_state
    entity_id: sensor.washing_machine_power
    below: 4
    for:
      minutes: 5
actions:
  - action: notify.mobile_app_phone
    data:
      title: Laundry is done
      message: The washing machine has finished its cycle.