Is a wall or wrist better for fall detection?

This story was originally published in my weekly newsletter on May 5, 2023. To subscribe, visit www.staceyoniot.com/newsletter. 

This week, I was testing the Aqara FP2 millimeter wave sensor. The device uses mmWave to detect people and their actions in a predefined space, and can trigger automations or send text-based alerts. In the first story of this week’s newsletter, I focused on how it performed as a presence sensor. Because it uses mmWave technology, it can detect how many people are in a room and where they are in said room, which enables home automation nerds to create some very specific automations.  (Here is the full review.)

But for this story, I wanted to evaluate the device as a fall detection monitor. It’s important to note that if you use it for that purpose neither the multi-person presence detection nor the ability to create specific zones will work; it will only detect falls. I also wanted to explore whether or not a ceiling-mounted sensor or a wrist-worn fall detection sensor, like an Apple Watch, makes more sense.

Installing the FP2 sensor as a fall detection device requires it to be mounted on the ceiling, at the edge of a room. The fall detection works best for low ceilings, specifically between eight and nine feet. The sensor also only measures falls in a radius of about six-and-a-half feet out. This, plus its ability to withstand humid environments, makes it a good option for a bathroom, but a poor option for a living room with a cathedral ceiling.

I tested it in our downstairs family room, which has eight-foot-high ceilings but is a bit larger than the recommended area size. After I placed the sensor in the room and calibrated it by moving to the rightmost and leftmost edges of the room, I also set up the app to alert me via notification when a fall was detected. And then the fun began.

Aqara specifically says you shouldn’t use the FP2 as a medical device, and after testing it I tend to agree. Possibly because I have an active family, with a 16-year-old and a dog, and the living room is also where we all work out, I ended up with a lot of fall notifications. Anytime my kid or I dropped quickly to our knees to play tug with the dog, I got a notification. Whenever someone plopped down quickly to do sit-ups, I got a notification.

Slower movements didn’t trigger notifications, nor did squats. But my fake trips and falls did. So it did a good job of letting me know when someone dropped rapidly down to the ground. But in my home that doesn’t necessarily mean a fall. It’s likely that with someone older, or someone frail, there would be fewer false positives. But then the question becomes whether a wearable makes more sense.

At $83 per sensor, and the fact that one might need several of them to cover an entire home, this sort of device could quickly get expensive. The $250 Apple Watch SE can detect falls and call actual emergency services when a fall is detected if the person also has an iPhone. And it doesn’t just work in rooms with low ceilings.

But the tradeoff with a wearable is battery life. If a person doesn’t charge their Apple Watch, it can’t detect falls. And at night, when someone is most likely to charge their wearable, is probably when they are most likely to fall. The other time is in the shower. And if the wearable is sitting on the bathroom counter, any fall will go undetected.

Perhaps a layered approach is best, or one in which the ceiling-mounted sensors are placed in bathrooms or bedrooms, where falls are more likely to happen when the wearable isn’t on. Other than on stairs, those are the places where falls tend to happen. And some people might not want a wearable. Some might not have an iPhone, which leaves them with few other options that don’t look like medical equipment.

So unfortunately I can’t say with certainty that the Aqara is the best option for fall detection. But it is an option. And if the shape and height of the rooms you want to monitor are within its sensing parameters and the price is right, it might be your best option.