Get notified when the dryer finishes
Detect a real drying cycle, wait through normal pauses, and send one alert when sustained vibration stops.
Best for: A dryer with a safe exterior mounting point and a vibration pattern that can be distinguished from nearby appliances.
Not for: A sensor mounted near heat, vents, belts, drums, controls, or other moving parts, or an ordinary smart plug connected to a 240-volt dryer circuit.
Why this exists
Dryers can pause, reverse, tumble intermittently, or run a cooldown phase. Nearby washers can shake the same floor. A useful completion alert must prove the dryer was running and wait longer than its normal quiet periods.
Vibration sensing is imperfect, but it is non-invasive and does not put an unverified relay in the dryer’s power path.
Logic
- Trigger: Vibration remains active long enough to prove the dryer started.
- Conditions: The sensor is available and the dryer was not already marked as running.
- Action: Mark the dryer as running and clear any previous waiting-laundry state.
- Wait / timeout: Wait until vibration remains inactive longer than the dryer’s longest observed pause or cooldown gap.
- Stop condition: Mark the cycle finished, send one notification, and set a waiting-laundry state.
- Manual override: A person can clear the waiting state without changing power to the dryer.
What I used
Detect dryer vibration
A battery vibration sensor mounted on a cool, fixed exterior panel. See vibration sensing gear for options.
Clear the waiting-laundry state
A manual dashboard or phone action. Do not assume one sensor can reliably detect both vibration and door position.
See the full gear guide for the job-first checklist.
Setup notes
- Find a fixed exterior panel that remains cool and does not block vents, labels, controls, or service access.
- Attach the sensor securely with removable mounting material suitable for the surface.
- Observe at least three full cycles, including cooldown and wrinkle-prevention behavior.
- Record the shortest sustained vibration that proves a start and the longest quiet period during a cycle.
- Run the washer by itself and confirm it does not mark the dryer as running.
- Create separate running and waiting-laundry states.
- Test with silent logging before enabling notifications.
- Add one completion notification, not repeated announcements.
Calibrate from evidence
The sensor’s location matters as much as its sensitivity:
| Test | Expected result |
|---|---|
| Dryer off, washer running | Dryer remains idle |
| Door closes firmly | A bump does not prove a cycle started |
| Full dryer cycle | Sustained vibration marks running |
| Normal pause or cooldown | Dryer remains marked running |
| Cycle completed | One alert after the calibrated quiet delay |
| Sensor unavailable | State becomes unknown, not finished |
If the washer and dryer cannot be distinguished reliably, move the sensor or use professionally installed circuit-level energy monitoring.
Advanced features
Add one restrained reminder
Set a waiting-laundry state after completion. Send one later reminder if it remains set, then let the household clear it manually or through a separately verified door sensor.
Respect wrinkle-prevention modes
Some dryers tumble again after the main cycle. Decide whether the household wants the alert at the main-cycle end or after all intermittent tumbling, then calibrate against that selected mode.
Monitor sensor health
Alert on a low battery or stale sensor before laundry day. Never interpret unavailable as no vibration.
Failure modes
- Washer activity marks the dryer as running: Reposition the sensor and require a longer sustained-start period.
- A door slam starts the cycle marker: Increase the start delay so a single bump cannot qualify.
- Alert arrives during cooldown: Lengthen the finish delay beyond the longest observed quiet period.
- No alert arrives: Confirm the sensor stayed attached, remained available, and set the running marker.
- Duplicate alerts arrive: Clear the running marker with the first completion event.
- The sensor falls or gets hot: Stop using that mounting point and inspect the sensor and adhesive.
- Someone tries to add a normal smart plug: Do not connect an ordinary inline plug to a high-voltage or high-current dryer circuit.
FAQ
Why use vibration instead of a smart plug for a dryer?
Many electric dryers use a 240-volt high-current circuit that a normal smart plug cannot safely monitor. A battery vibration sensor is non-invasive when mounted away from hot and moving parts.
How long should vibration be absent before the dryer counts as finished?
Measure the dryer’s longest normal pause and cooldown behavior, then use a delay comfortably longer than that observation.
What if the washer makes the dryer sensor vibrate?
Reposition the sensor, require sustained vibration before marking the dryer as running, and test washer-only cycles before trusting the alert.