Motion Sensors (PIR)

PIR sensors (motion): automatic actions based on presence

A PIR sensor (motion sensor) is one of the most practical Smart Home upgrades, because your home immediately starts “responding” to you. Instead of switching things manually, you use presence as a trigger: lights automatically on in the hallway, a notification when there’s movement at night, or a routine that activates security when you’re away. PIR stands for Passive Infrared and detects changes in heat/infrared, which allows it to detect movement from people (and sometimes pets). That makes this type of sensor ideal for areas where you’re often only briefly, such as the hallway, landing, toilet, storage room, or entrance.

What can you automate with a PIR motion sensor?

The power of a PIR sensor is the combination of detection + action. Depending on your Smart Home platform and settings, you can for example:

• Automate lighting: on when you enter, off after X minutes without motion (perfect for halls/stairs).
• Set notifications: push alerts for motion at unusual times or when your “Away” mode is active.
• Enhance security: use PIR as an extra detection layer alongside cameras or an alarm system.
• Trigger scenes: “Night mode” (soft lighting), “Arriving home”, or “Away” based on activity.

What to look for when choosing a PIR sensor

For a reliable everyday experience, it’s mainly about practical factors: placement, detection behaviour, and ecosystem compatibility. Ideally, choose sensors you can manage centrally in the same environment as your other devices (so expanding later stays easy). Also pay attention to detection angle and range (especially in long hallways), and consider whether you have pets—then you’ll often want a sensor that’s less sensitive to low-level movement or has good adjustability.

Using a PIR sensor: quick placement tips

• Aim the sensor at the walking path, not directly facing a window (changing sunlight can cause false triggers).
• Mount it at a height that fits the space (hall/landing) and test the detection angle before fixing it permanently.
• Use a delay timer (e.g. switch off only after 2–5 minutes without motion) to prevent annoying “on/off” behaviour.

Relevant categories

• Smart sensors – the complete overview of sensors and use cases.
• Smart security – combine detection with cameras, doorbells, and alarms.
• Smart alarm systems – make PIR detection part of an alarm scenario.
• Smart Home – all categories and building blocks in one place.
• LED wall lights with sensor – if your main goal is “automatic light” with built-in (PIR) detection.