Turn off lights with Elgato Eve Motion
Updated for iOS13: 18 Oct 12019
A battery powered, hub-less motion sensor with HomeKit support? Sounds like it has potential, I thought to myself. Sure, it has some limitations. Since iOS 11 these Bluetooth devices can deliver sub-second response time with good signal strength, fast enough for automated lighting control (when HomeKit is behaving itself). So far it seems to work as advertised, and setting up an event in Apple's Home app to turn on lights when motion is detected was trivial.
What I found a bit more difficult, and after looking for answers seems to be a common question, is how to turn them off again once the motion stops. A little experimentation yielded success, so I thought I'd write it up for those looking to do similar.
With the Eve Motion there are actually two ways to do this, and each is suited for different scenarios. The first is if you want to have the motion sensor turn on the lights when someone comes into a room, and then turn them off again automatically after a define period of no motion.
The second is if you want to have the motion sensor only manage turning off the lights after that period of inactivity, but they have been turned on by another automation, or manually (via the app, Siri, or a smart switch of some kind).
Eve Motion Settings
Key to both of these options is a feature unique to the Eve Motion where you can specify a duration value. HomeKit recognizes two states for a motion sensor accessory, Motion and Clear. Normally a motion sensor will simply report Motion while it is actually detecting something, and the revert to Clear immediately. This is fine for our first case, but not the second. The Eve app allows us to specify how long the Eve Motion will stay in a Motion state, which allows the extra flexibility we need for case two.
Setting this is fairly easy, just go into the Eve app (you’ll need to have that installed on your iPhone). the go to Settings on the bottom menu, tap Accessories from the list, then tap on the motion sensor you want to configure.
In the middle section will be the Duration value. You can also set the sensitivity you want here which will depend on how open the space is that you are monitoring with the sensor.
Case 1: Turn on and off automatically.
Back in the iOS Home app we want to add a new automation by tapping the bottom Automation button, then the + in the top right corner.
From the list of options to kick off the automation, select A Sensor Detects Something.
Select the sensor to use from the list and then tap Next.
In this case, we want to turn on the lights first, so we’ll leave the default Detects Motion ticked. You can optionally specify a time for the automation to run, and it is here we can specify At Night to prevent lights coming on in the day time. If the room in question is typically dark, you may want to have the lights come on regardless, so we can also leave this as Any if you prefer.
Note that you can tap the info icon next to the time selection to adjust the specific times period, but leaving it as default lets HomeKit determine when night is based on the location of you home and the time of year.
Tap Next to move onto the light selection, which you can activate via a scene if you have one for the lights you want to turn on, or simply select the lights from the accessories list further down the page. Tap Next again.
Now we finish off the automation by ensuring the selected lights are set to Turn On (just tap to toggle it if it’s not), then tap the Turn Off line at the bottom, this is where we select when to turn the light off.
Now, here it is important to select a time period longer than the duration value on the Eve Motion. HomeKit will start this count down from the time the sensor goes into the Motion detected state, and it will reset the timer every time the Motion state is reported again. This ensures the lights don’t turn off while someone is still in the room, but if the Eve Motion doesn’t revert to Clear before this time is up, then it will not be able to reset the timer before it expires. For this scenario, we can set the Eve duration to a low value, say 1 minute.
Case 2: Turn off regardless of what turned them on
In this case, we may have a scenario where you just want to save power by turning off lights than are manually controlled when no motion is detected, or you may have another sensor that turns them on (say a security camera), and you want a way to turn them off again afterwards.
For this, the duration value in the Eve app is critical. This is what will determine how long to wait before turning them off, so we’ll want a longer value this time, say 10-15 minutes.
We’ll need to create an automation largely as above, but we’ll select Stops Detecting Motion on the When: page, and leave the time as Any.
For the accessories we’ll need to have them set to Turn Off, or a scene that does this specifically for the lights we want to control.
If this is set correctly, the Turn Off option will not be present. The Home app knows that doesn’t make sense thankfully.
This automation will handle turning off the lights no matter when or why they are turned on after the duration value on the Eve Motion has expired. As with case 1, the Motion state will be reset by further motion in the room, and ensure the turn off automation is triggered only when the motion has stopped for long enough.
