Turn lights on when you walk in
Walk in, lights on. If that fails at 2am, the wall switch still works.
Best for: Hallways, closets, entryways, laundry rooms, and bathrooms with a sensor that sees the door.
Not for: A room where people sit still for long periods, or a bathroom with a short PIR timer. A PIR is best for detecting entry motion. Use a longer timeout and the PIR vs mmWave presence article where the automation must know that someone is still in the room.
Why this exists
Nobody should have to fumble for a switch with a basket of laundry or explain the light system to a guest. The first detection needs to happen before a hand reaches the wall control. Keep the switch useful so the room remains ordinary when the hub, sensor, or internet is not.
Use cases
Indoor automation
- Nighttime navigation - Bathroom lights turn on at low brightness when you get up at night
- Home office - Lights automatically turn on when you enter your workspace
- Hallways - Lights turn on as you move through the house
- Closets - No more fumbling for switches in dark spaces
Outdoor automation
- Garden shed - Motion sensor triggers light when you enter
- Porch light - Automatically lights up for guests and delivery drivers
What I used
| Job | Good enough | Never think about it | Notes |
|---|---|---|---|
| Detect fast entry motion | Shelly BLU Motion ZB | Aeotec SmartThings Motion Sensor - my favorite for fast reactions | Mount it where it sees the approach to the doorway. |
| Dim a fixed light | TP-Link Tapo S505D Matter Smart Dimmer Switch | UltraPro Z-Wave Long Range Dimmer | Verify hub compatibility. Keep the physical paddle usable. |
| Switch a fixed light on or off | Leviton DG15S Zigbee switch | UltraPro Z-Wave Long Range On/Off Switch | Keep the physical paddle usable. |
For a bathroom that needs humidity, temperature, and light readings too, use the Zooz ZSE11 800LR Q Sensor instead. It is not my first choice when the fastest motion response is the job.
See recommended gear for the job-first checklist. Product links on this page are direct, non-affiliate Amazon links. Product recommendations and any future affiliate relationships are explained in the disclosure.
- Use sensors specifically rated for outdoor use (IP65 or higher)
- OR protect indoor sensors with weatherproof enclosures
- OR place sensors under eaves to avoid direct water exposure
Logic
- Trigger: The entry sensor changes from clear to motion detected.
- Conditions: The room is dark enough, or it is within the hours you want automatic light.
- Action: Turn on the light. Use a dim level at night if the light supports it.
- Wait / timeout: None for turn-on. The paired turn lights off after motion stops recipe owns the timeout.
- Stop condition: A manual wall-switch change should prevent the off recipe from undoing the person’s choice.
- Manual override: The wall switch still wins.
Setup notes
Start with only the trigger and light action. Once that is reliable, add the daylight condition and any night brightness adjustment.
- Daytime: Leave the light off when daylight is sufficient.
- Evening: Use the brightness that makes the room useful.
- Deep night: Start at 10 to 20 percent and raise it only enough for safe navigation.
Advanced features
Multiple brightness levels
Create different levels throughout the night:
Lux-based activation
Only turn on lights if the room is actually dark:
- Add a condition that light level must be below a certain threshold (e.g., 100 lux)
- This prevents lights from turning on during daytime when natural light is sufficient
Zone-based motion
For larger rooms, use multiple motion sensors to track which area someone is in and only light that zone.
Common issues and solutions
Lights turn on too slowly
- Check sensor placement - should detect motion before entering room
- Reduce automation processing time - use local control instead of cloud
- Use faster communication protocols (Zigbee/Z-Wave vs WiFi)
- Optimize automation logic to minimize conditions
Lights turn on when not needed
- Adjust motion sensor sensitivity
- Add lux sensor condition to prevent daytime activation
- Use pet-immune motion sensors
- Position sensor away from windows and heat sources
- Add time-based conditions
Inconsistent performance
- Check sensor battery levels
- Verify wireless signal strength (Zigbee/Z-Wave mesh)
- Replace batteries before completely dead
- Add repeaters/extenders for distant sensors
- Check for interference from other devices
Sensor placement best practices
Height
- Optimal: 6-8 feet high for best coverage
- Corners: Good for monitoring entire room
- Entry points: Near doors for immediate detection
Angle
- Ceiling mount: Wide coverage, detects all motion
- Wall mount: Directional, catches people entering
- Corner mount: 90° coverage, good for hallways
Coverage testing
- Mount sensor temporarily with tape
- Walk through room at different paths
- Verify all entry points are covered
- Check for dead zones
- Adjust position or add additional sensors
- Permanently mount once confirmed
What to avoid
- Near windows - Sunlight and outdoor motion cause false triggers
- Near heating/AC vents - Temperature changes trigger sensors
- Pointed at moving objects - Ceiling fans, curtains, pets
- Behind furniture - Blocks detection zone
Failure modes
- The light turns on after someone reaches the switch: Move the sensor to see the entry path earlier and keep the path local.
- It turns on in daylight: Add a light-level condition, then test it on a bright overcast day as well as at night.
- A guest stands still after the light turns on: This recipe should be paired with a conservative off timeout. Use presence sensing where stillness is normal.
- The sensor is hidden or affected by steam: Keep it clear of towels, furniture, vents, and the shower plume.
- The hub or internet is down: The physical switch remains the fallback. Verify any Level 2 automation is local before depending on it.
Done when
- Walk in from every usual entry path and the light is on before your hand reaches the switch.
- During daytime, the light stays off when the room is already bright.
- Turn the wall switch on or off and confirm the paired off recipe does not immediately reverse that choice.
- Disconnect the internet, if your setup supports local control, and verify the automation still works.
- Have someone who did not build it try the room without instructions.
FAQ
Why do motion lights turn on too slowly?
Put the sensor where it sees someone before they reach the switch, and keep the automation local where the platform supports it.
Should motion lights turn on during the day?
Usually no. Add a light-level condition or restrict the recipe to the times when the room is normally dark.
What happens when the internet is down?
A local hub and compatible devices can keep the automation running, but the physical wall switch must work either way.