Elgato Eve Motion is a standalone motion detection sensor that’s compatible with Apple’s HomeKit feature. Eve Motion can be used as a sensor in iOS 10’s Home app to trigger scenes and control accessories.

When added to Apple’s Home app, Eve Motion ($49) appears just like other HomeKit motion sensors. You can see when sensors are armed and ready, when sensors are activated by motion, and check values like battery level and charging status.

You can optionally enable notifications for motion sensors including Eve Motion so the Home app sends you an alert each time motion is detected, but for me the value is mainly in using Eve Motion as a trigger for automation. For example, you can use Eve Motion to automatically turn on a HomeKit lamp when motion is detected after sunset with a few steps.

From the Automation tab of the Home app, select Create New Automation then tap A Sensor Detects Something. From here you can select Eve Motion as the automation sensor, then select which scene or device you want to react when motion is detected. After you make your selection, you can toggle on the option to trigger the automation only after sunset and set the state of what you want controlled (like lamp on at 100% brightness) then tap Done to save the automation.

Eve Motion works reliably as a motion sensor, but you may want to increase the sensitivity. In testing, I found that I could enter my office in the dark for several seconds without triggering Eve Motion (Elgato promises 2 second response time) and automatically turning on the desk lamp when using the default sensitivity level. After some poking around in Eve’s companion app, I turned up the sensitivity level from low to high (and there’s a medium level too) which noticeably helped.

Eve Motion relies on Bluetooth Low Energy for connectivity and runs on two AA batteries so increasing the motion sensitivity likely negatively impacts battery life.

The biggest issue for me with motion sensors and automation in Apple’s Home app is what appears to be a missing feature in my experience. It’s easy to turn a light on when motion is detected, but Apple’s Home app doesn’t appear to support automatically turning a light off when motion is no longer detected. (If this is supported in Apple’s Home app, I’m not aware of it and haven’t discovered it.)

Ideally, I’d like to be able to turn off the desk lamp if no motion has been detected for, say, 30 minutes. This may be possible when configuring automation through Eve’s companion app, but my interest is primarily in configuring Apple’s Home app and not managing a folder of accessory apps.

Physically, Eve Motion is the same size as other Elgato smart sensors (80 x 80 x 32 mm) like Room and Weather, but larger than Ecobee’s remote sensors with motion detection and HomeKit support. Eve Motion can be placed on a flat surface and stand on its own without using a stand, or Eve Motion can be mounted on a wall.

Elgato promises a 120º field of view and 9 meters or 30 feet range when mounted 2 meters or 6.5 feet above floor level.

In practice, Eve Motion works on par with Ecobee’s remote sensors which were recently updated to support HomeKit as motion (and temperature) sensors. The main difference is that you need an Ecobee 3 thermostat ($249)to use Ecobee remote sensors (2 for $79).

If you plan to use the motion sensor at an entryway, Eve Motion is definitely the better solution even if you have an Ecobee 3 thermostat. Eve Motion is a standalone motion sensor whereas Ecobee’s remote sensors also capture temperature data that affects thermostat settings so outdoor use is out of the question. Ecobee’s remote sensors are smaller and run on a CR2032 that lasts for 18 to 24 months (although one of my sensors lasted for 14 months).

I haven’t tested Eve Motion for long enough to gauge battery life, but my other Elgato sensors powered by AA batteries generally last 2 to 3 months before needing new batteries so that’s something to consider as well. [Update: Elgato actually documents battery life by product here; Eve Motion is rated for over 1 year whereas Room is rated for the 3 months that I’ve observed. Updating batteries annually is reasonable and good to learn.]

At this point, Eve Motion and motion sensors in general are more experimental than essential in my HomeKit setup. Lights, locks, and a thermostat are key accessories, but Apple’s Home app needs to learn a few more tricks before motion sensors are as useful as they could be for me personally.

Still, if you’re interested in HomeKit and want to see what motion sensors can do for your setup, Elgato Eve Motion ($49) is the standalone motion sensor to purchase.