“Smart” lights aren’t very smart if you have to wave your arms around in the dark like you’re trying to land a plane.

This is the all-too-common failure of the standard smart home. Most “motion” sensors are technically Passive Infrared (PIR) sensors. They work by detecting big changes in heat—like a person walking into a room. The problem? If you sit still for a few minutes to read a book or watch a movie, the sensor thinks you’ve vanished, and… lights out.

The solution to this has long been millimeter-wave (mmWave) radar. This is the “presence” sensor you’ve probably heard about. It’s so sensitive it can detect the micro-movements of you just breathing, making it the holy grail for truly “set it and forget it” automation.

But mmWave has always had one, giant, tangled problem: a power cord.

This high-tech sensing has always been too power-hungry to run on batteries, forcing you to design your smart home around where your power outlets are. Want to put a sensor on the ceiling? Good luck. Tucking one onto a bookshelf? Get ready to hide that ugly USB cable.

This is why Aqara’s latest announcement is quietly one of the biggest leaps for practical home automation we’ve seen in a while.

Finally, the cord is cut

Aqara has just announced its first-ever battery-powered presence sensor, the Presence Multi-Sensor FP300. And on the surface, it looks like any other sensor. But its ability to ditch the power cord changes everything.

Instead of being tethered to a wall, the FP300 runs on a pair of simple CR2450 coin cell batteries. This simple change means you can actually put it anywhere. Mount it on the ceiling for perfect top-down room detection. Stick it in the corner of a hallway. Place it on a high shelf where no cable could ever reach.

This is the flexibility we were always promised.

And Aqara claims the battery life is staggering for this kind of tech. If you’re using it with a Zigbee 3.0 setup (which integrates with the Aqara Home app), the company estimates up to three years of battery life. If you’re running it on the newer Matter over Thread standard, you’re still looking at an impressive two years.

It’s available right now on Amazon and Aqara’s own website for $49.99, a pretty aggressive price point for what it’s offering.

So, how does it work? The FP300 is actually a hybrid. It uses a combination of that classic PIR sensor for instantaneous motion detection (so the lights turn on the second you walk in) and the high-precision 60GHz mmWave radar to confirm you’re still there (so the lights stay on).

This dual-sensor approach, combined with optimized software, is likely the secret sauce behind its impressive battery life.

The sensor can reliably detect a person—moving or perfectly stationary—up to 20 feet (about 6 meters) away. This is more than enough for most living rooms, bedrooms, or offices.

But it’s not just a presence sensor; it’s a multi-sensor. Tucked inside that small white puck are three other crucial sensors:

1. Temperature sensor: Lets you trigger your smart thermostat or fan based on the actual temperature in the room you’re in, not just where the thermostat is on the wall.
2. Humidity sensor: The perfect trigger for automatically turning on the bathroom fan when someone’s taking a shower and turning it off when the humidity drops.
3. Light (lux) sensor: This is the key to energy efficiency. It allows you to set automations like, “If you detect presence and the room is dark, then turn on the lights.” No more lights blazing at full power on a sunny afternoon.

With both Zigbee and Matter over Thread support, the FP300 is built to be a team player. It’s designed to work natively with just about every major ecosystem, including Apple Home, Google Home, Amazon Alexa, and Samsung SmartThings.

The tradeoffs: what you don’t get

To achieve this battery-powered freedom, Aqara did have to make some compromises, especially when compared to its more “pro” (and wired) big brother, the Aqara FP2.

The FP300 is a “simpler” device. It knows if someone is in the room, but that’s about it.

The wired FP2, by contrast, is a miniature radar station for your house. It can track multiple people at once, create “zones” within a room (so it knows if you’re on the couch vs. at the desk), and even offers fall detection and sleep monitoring with real-time heart and respiratory rate tracking.

The FP300 does none of that. It can’t tell the difference between one person and three, and it can’t track your vitals.

But for 99% of smart home users, that’s perfectly fine. The FP2 is a power-user’s dream; the FP300 is a practical solution for a universal problem. It’s not about mapping your room in 3D—it’s about making your lights work, your thermostat smarter, and your fans run only when they need to, all without drilling holes in your walls or tripping over cables.

And for that, it might just be the most important presence sensor on the market.