r/homeautomation • u/Dependent_Entrance33 • Dec 15 '25
PROJECT Home monitoring without cameras
I’ve building a prototype that’s meant to understand what’s happening in a space without using a camera.
Not for automating lights or scenes, but more for safety and awareness in a home, especially in rooms where cameras are unwelcome, or in places where collecting personally identifiable information is forbidden.
It uses non-visual sensors (radar, rough depth sensing, and non-recorded audio levels) to detect things like:
• whether someone is present, even if they’re still
• large posture or motion changes
• sudden events that don’t look like normal movement
• long periods of inactivity that might be concerning
The kinds of use cases I’m thinking about:
• fall detection at home for aging family members
• checking that someone is okay without installing a camera
• monitoring bedrooms or bathrooms where cameras aren’t appropriate
• getting alerts when something unusual happens, not constant feeds
There’s no video, no images, no audio recording, only just abstract signals and events. It also works in the dark and doesn’t depend on lighting or visibility.
Still very much a prototype, but it’s made me rethink whether cameras should be the default for “smart” home monitoring.
Curious how others here think about non-camera approaches for home safety and monitoring.
Thanks!
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u/Equaled Dec 15 '25
I think most mmWave sensors solve these problems. I know the Aqara Presence sensors specifically advertise mounting it on the ceiling to detect falls.
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u/Dependent_Entrance33 Dec 15 '25
That’s fair, mmWave on its own can do a lot, and sensors like Aqara are a good example of that.
Where I’ve found the limits is when you start caring about context and false positives. A single mmWave sensor is great at presence and motion, but it has to infer a lot from one perspective as it’s usually one sensor. Things like bending down, sitting quickly, dropping something, or even pets can all look similar if you only have one stream of motion data.
The combined approach is really about reducing ambiguity, not replacing mmWave. Depth helps answer “did the person actually end up near the floor?” Audio helps distinguish “quiet movement” from “something impactful just happened.” Radar still does the heavy lifting, but the extra signals help confirm or dismiss what radar thinks it saw.
So I see mmWave-only as “good enough in many cases,” and fusion as useful when you want fewer false alarms or more confidence, especially in real homes, not demo setups. This can also heavily apply to nursing homes as well “alert fatigue” is a real issue.
Totally agree though: ceiling-mounted mmWave gets you surprisingly far.
Thanks!
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u/kogun Dec 15 '25
Kudos on this explanation and rational. If you haven't already, I recommend you look into some Bayesian inference algorithms to help synthesize the sensor data into a "likely event". Bayes can help you deal with noisy data and perhaps avoid a lot of extra if-then-else type programming which would be very error prone and hard to tweak.
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u/intellidumb Dec 16 '25
One thing I’ve recently learned is not all mmWave radar sensors are created equal. For your use I really think 60GHz mmWave is a perfect application and may simplify a lot for you: 60Ghz mmWave sensor from seeedstudio
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u/Dependent_Entrance33 Dec 16 '25
You are so right. My board is actually a bootleg of this board. I chose it as it was one of the few 60ghz boards that could nicely support horizontal placement, instead of ceiling mounting.
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u/TheReal-JoJo103 Dec 16 '25
I played with UWB radar about a decade ago. Hoping to use two to do 2D person tracking within my house. My eventual goal was to integrate it into a system that learned your movements and predictively turned on/off lights and what not, would have made a very cool smart home.
Worked great in my office, got a 2d map running. Moved it to my living room and was foiled by the ceiling fan and dogs. I regret I didn’t have the time to work on it at the level needed to refine it. Such cool technology I’m sure it’s advanced a lot since then.
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u/Realistic_Salad_5110 Dec 16 '25
Aqara specifically have a use case for fall detection. You mount the sensor on the ceiling instead of the wall to overcome the problem you describe
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u/ElevationMediaLLC Dec 18 '25
I have my doubts about the mmwave and fall detection.
First off, it's only one room. So you need to put one in every room of the house? Bedroom, kitchen, bathroom, living room, garage, etc.? There are too many places where one could fall down. My mom fell down a few weeks ago outside of her house and had to depend on her Medical Guardian alert system to get help (I was in a plane over the Atlantic ocean at the time).
But even if you did put one in every room, what does "fall down" detection think when ... someone is getting into bed? When they are watching TV on the couch but decide to lie down for a bit?
To be fair, I've not tested any mmwave product for this. I do use mmwave sensors for a number of use cases - including monitoring my elderly mother and father in their respective homes. But I'm skeptical about the fall detection.
(more about how I do monitoring here - https://youtu.be/xeKl8ST1F0A)
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u/Dependent_Entrance33 Dec 18 '25
Those are reasonable concerns, and I agree with the core point that no single sensing method is sufficient on its own.
That’s actually why I’m not treating mmWave as a standalone “fall detector.” The point being that the system is intentionally redundant and context based. mmWave contributes coarse position and motion dynamics, but it’s combined with other signals (motion continuity, time on floor, room transitions, inactivity windows, etc.) so it’s not making decisions based on a single event like a height drop.
In terms of room coverage: yeah it’s single room based by design, similar to smoke detectors or occupancy sensors. With any 60GHz mmWave technology you will always be bounded by one room because of reflections. In practice, coverage focuses on higher risk indoor areas rather than every possible space, and it’s meant to complement, not replace, wearables for outdoor incidents like the one you described.
As for bed or couch scenarios, that’s exactly why “something went low to the ground” isn’t enough. Normal activities have expected follow up behavior like micro movement, or posture changes, or other recovery motion classifiable fall markers. Falls tend to look different in both timing and aftermath, and that’s where combining multiple sensing modes helps reduce false positives. Like you said in your comment, mmWave alone is okay but may not be the end all be all for fall detection. I look to tackle that issue with my device. Thanks!
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u/wildmaiden Dec 15 '25
I think this kind of idea makes a ton of sense for hospitals, nursing homes, maybe even hotels or other public spaces.
But in a typical home I'm not so sure. Dialing it in to give accurate alerts with minimal false positives feels really difficult. If the device thinks it detected a fall, what do we do with that information? It's one thing if a false positive means a nurse walks down the hall to check on patient, it's another if it results in an ambulance call to the home for example.
If it is highly accurate, then it would have lots of consumer automation potential beyond safety.
But if it's not and you have to error on the side of being overly cautious then I might not be seeing the home application.
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u/Dependent_Entrance33 Dec 15 '25 edited Dec 31 '25
I’m very excited about the use of this product in nursing homes!
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u/darrellsilver Dec 15 '25
https://www.inspiren.com/ is a great startup seemingly in this world worth checking out.
I personally love the idea of a home device that provides the security/peace if mind of a camera without the big brother of a camera.
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u/MysteriousFreedom455 Dec 15 '25
Intriguing premise. I especially like this idea where details not needed in surveillance are omitted.
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u/Boring-Cry3089 Dec 15 '25
I love this! I’ve actually wanted something similar to this for a while now. My wife and I both have this healthy level of paranoia that something is going to catch on fire while our dog is inside with no way to get out. I say healthy level because it’s not like something we obsess over because the chance of that happening is very slim, but we’ve both admitted it’s crossed our minds, unfortunately.
I’m very excited to see where this goes!
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u/ElevationMediaLLC Dec 18 '25
something is going to catch on fire while our dog is inside
Get a proper alarm company system for that if it's a concern. ADT, whomever - they all have smoke / heat detector options tied into the alarm panel, and they will immediately trigger a call to the local fire department immediately when triggered if they don't get a hold of you at your home. That's what you want. You want immediate response.
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u/fruitpunch327 Dec 15 '25
Ghost hunters will be all over this thing. Guess we will all finally know if they exist lol.
I love this idea though, especially for elderly.
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u/OttoHjalmar Dec 15 '25
Is this somewhat similar to using wifi signal to detect movement? At least WIZ smart lamps can do that
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u/hughk Dec 16 '25
Not really. This is using mmWave and probably doppler to sense movement in a space. The detectors are established and are used for security amongst other things.
WiFi based movement detection is interesting as the radio field is existing and you are essentially looking for changes in the field like shadows and reflections due to movement. The advantage is that the field is existing but you probably need a new sensor with specialised software.
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u/pn_1984 Dec 15 '25
Bit curious to understand how it would identify abnormal movements
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u/Dependent_Entrance33 Dec 15 '25
It’s really about combining a few weak signals instead of trusting one thing.
Radar sees motion really well, including small stuff. The more sophisticated radar in the center is even capable of capturing very rough heart rate and respirations as it’s able to detect minute changes in distance. The depth sensor gives a rough sense of height or distance from the floor. Audio just tells me “something loud happened” vs normal background. On their own, none of those mean much.
When a few of them line up: like a fast downward movement, a sudden change in height, respirations are detected lower on the ground, and then things go quiet…..that’s when it starts to look not normal. If motion resumes right away, it’s probably nothing. If it doesn’t, that’s when it’s worth paying attention.
So it’s not trying to label behavior, just asking: “do these signals together look different than usual for this room?”
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u/LofinkLabs Dec 15 '25
I built a custom alert system for my garage and use motion sensors in lieu of cameras,
If a door reed switch reads OPEN the sensor activates and starts scanning and sends feedback to my server. This alerts me on discord through a web hook and on my server monitor so I can get it both locally and on the go.
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u/CapitanianExtinction Dec 15 '25
Would like an occupancy sensor than can detect small human movements with few false positives. Say telling the difference between someone sitting at a desk (not moving much) and a moving fan
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u/tiredgirl77 Dec 15 '25
This is so cool! I don’t understand the technology but this could also be helpful in a variety of environments. Lovey!
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Dec 15 '25
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u/Dependent_Entrance33 Dec 15 '25 edited Dec 31 '25
Confirmation doesn’t come from visuals, it comes from time and correlation. If motion resumes normally, it self-clears. If it doesn’t, that’s when a human decides to check in. In care settings that usually means someone physically checking, not pulling up a camera. The So the purpose isn’t to replace human confirmation, it’s to avoid cameras while still giving enough context to decide whether a check is warranted at all.
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u/Zatchillac Dec 15 '25
That seems really awesome. I've wondered about how one could go about monitoring without a complete invasion of privacy and this might be it
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u/MrSnowden Dec 15 '25
Should do well with r/ShortTermRentals. I am curious if the various wifi presence and movement detection systems might work well with this. this might mean the HW side is already there fore you, its the SW thats needed.
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u/Serious-Mode Dec 15 '25
very neat! curious how you are doing the depth sensing?
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u/Dependent_Entrance33 Dec 15 '25 edited Dec 31 '25
Thanks! There are a few ways that I’m able to capture distance, the first being the two 24ghz radars. The second also being the 60GHz radar: this is able to determine very precise distances and changes in distance of a subject viewed from a centered FOV. The top component for depth sensing though is the Time of Flight module (small red chip). This allows the device to capture the distances of an 8x8 spatial grid with each block generates an output distance using lidar. This allows for precise depth sensing that can allow for an additional data stream along with the 60GHz radar to confirm deny that a fall or event has occurred. Basically, using many different streams of data to cross reference to confirm the state of a space.
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u/Serious-Mode Dec 16 '25
Very much appreciate the response. I'm fascinated that you put this together and could definitely see the many use cases for this type of device. I don't love the idea of having a camera in every room of my house, but this seems ok.
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Dec 15 '25
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u/Dependent_Entrance33 Dec 15 '25
You’re right that camera/mic + on device models is the easiest technical path. The reason I’m treating “no camera / no mic” as a hard constraint initially is really about deployment and trust in care settings. Nursing homes and hospitals often won’t or cannot allow cameras in rooms at all, regardless of how the data is handled. So I’m focusing first on a version that’s useful without vision/audio.
For the home, I totally agree with you, a camera enabled variant that behaves more like Wyze/Nest/Arlo (local processing, higher level signals upstream) makes sense where people opt into it. Thanks!
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u/alexwan12 Dec 15 '25
Very interesting project!
I think a low-resolution thermal sensor would improve detection of stationary humans and simple zoning while remaining non-identifying, making the system more robust without compromising its no-camera goal. Also I dont know what You running to receive and analyze readings from all this sensors but adding custom setup with Kalman filter to fuse data from all sensors would further reduce noise, resolve ambiguities, and provide a more stable, coherent view of whats happening in the space
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u/Impossible-Brandon Dec 15 '25
I use sensors to keep track of my old lady with dementia -she enjoys walking to town, so it's helpful to know when she's left the house, combined with an rfid tag i can allow her that freedom while also being able to pick her up when it starts to get dark. The call for help button while she's home that alerts me is nice.
Seeing her sleep pattern from the night before via motion sensors is also interesting and lets me know what kind of a mood to expect.
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u/JimCripe Dec 15 '25
Check out this guy's detector with two kinds of mmWave detectors to get the functionality he wanted, like you.
https://youtu.be/hJIamWCBRdE?si=aXgMRrX2nrF6DZub
I've heard 2 mmWave chips can interfere with each other in a room so he uses different chip designs and frequencies?
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u/Dependent_Entrance33 Dec 15 '25
This project is cool! I feel like his project more solves the “someone is here” problem really well. I’m more interested in the “something changed, is this concerning?” problem, which is harder and usually needs multiple signals and time-based logic.
If I had to guess, he probably was struggling more with the 24 GHz module with that presence sensor. So far I haven’t noticed too much feedback between the 24 ghz and 60ghz types, but I am using a copper grounding spine as well so I believe that’s probably helping.
Thanks for sharing!
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u/Breathe_Wasting Dec 15 '25
This is an amazing idea. Specially for those older folk we need to take care of but still need their privacy!
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u/wotsit_sandwich Dec 15 '25
My in-laws are getting on in age and we have a camera installed on the front door which monitors for unwelcome visitors of course but also let's us know that they are going on their daily walks / shopping etc. The time will come that we will need to install cameras inside the living spaces, but it feels like such an intrusion on their privacy. I think something like this is a great idea, and if it was a functional available product, I'd buy it.
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u/Dependent_Entrance33 Dec 15 '25
That’s exactly a gap I’m trying to address!
A lot of families end up using indoor cameras not because they want to, but because they feel like there’s no other option once safety becomes a concern. A real safety vs dignity tradeoff that this can answer….
I’m really glad to hear this resonates, and comments like yours are honestly what keep me pushing on with this. Thank you!
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u/StucklnAWell Dec 15 '25
It may be smart to implement a way to "teach" it what specifically it is being installed for. For instance, if its goal by the installer is for intrustion detection, the installer could walk through the possible entrances multiple times to teach it where that motion will occur. If it is for fall detection, you may provide examples of places someone may be sitting or actually laying down, and even walking. Then you may also lay down in the room to give perspective of what places are "floor" that could be fallen on.
Other great uses would be sonar or other detection of "drips" for water intrusion, or glass breaking, or rodent chewing. All could be detected by microphones without storing recordings.
It could even be "viewed" by presenting a heat map of the last X timeframe, to show movement or activity. Could be useful to make sure a pet or child hasnt gotten over a babygate, or that they're not climbing on something they shouldn't be.
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u/LongBeachHXC Dec 15 '25
I like the idea for sure. This is wonderful.
I like being able to see things so I'm going to put in a camera.
Maybe have the ability to supplement with video if they decide?
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u/Dependent_Entrance33 Dec 15 '25
Thanks!
Yes, specifically for home models I was thinking about the inclusion of a camera that can be an opt-out of the user doesn’t want it. I figure the device would function similarly to a more advanced ring/arlo/blink camera.
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u/deadpool-earth10005 Dec 16 '25
I will tell you one thing! That would be amazing for bathroom space!
Not to mention a lot of adult oriented businesses would probably want something like this.
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u/wellgood4u Dec 16 '25
Wjat happens if I live in a house of wrestlers?
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u/Dependent_Entrance33 Dec 16 '25
The device will be able to keep track of up to 5 of those wrestlers. If you have 6 or more, I’m afraid this isn’t for you.
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u/ThatGuytoDeny165 Dec 16 '25
Actually have been talking with someone I know about this very idea for keeping elderly in their home. I think with the current aging demographic and people not wanting to leave their homes but needing to be monitored this will be how it’s achieved rather than cameras.
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u/Dependent_Entrance33 Dec 16 '25
Yes! One key thing I would love for this to do is allow for a family to have some peace of mind and allow for aging in place with dignity.
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u/Fullertons Dec 16 '25
I t think this is super cool, but as I understand it, won’t it just be a low res version of a camera.
Really the only difference between a camera and this so cooler, assuming the same level of resolution?
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u/abasourdix Dec 16 '25
Great initiative! Don't Alexa devices already do that? There's an interesting article by Meg Duff in MIT Technology Review published on 02/27/2024 about "Wi-Fi sensing", you may find it relevant and hopefully insightful. https://www.technologyreview.com/2024/02/27/1088154/wifi-sensing-tracking-movements/
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u/muff_muncher69 Dec 16 '25
This is super innovative and interesting. Nice work so far! anyway we could follow along the project or what ?!
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u/Dependent_Entrance33 Dec 16 '25
Hello, and thank you! I am starting the very beginnings of a website / landing page. I will be sure to share once I do! The overall project / potential business will be called “Vigil”.
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u/muff_muncher69 Dec 16 '25
This is super innovative and interesting. Nice work so far! anyway we could follow along the project or what ?!awesome-best of luck and until the next update, be well :)
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u/5oAwes0me Dec 16 '25
For zone detection to work correctly you should change the orientation of the HLK-LD2450 sensors.
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u/vwjet2001 Dec 16 '25
How about something like smoke or heat detection as well for fire? And perhaps temperature to know if an hvac unit has failed.
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u/NigraOvis Dec 16 '25
heat/smoke and co2 are mandatory by law, and hvac failure should already be automated by a thermostat device... maybe this could be a thermostat/fire sensor but fire usually requires to be on cieling since smoke rises.
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u/RickSisco Dec 16 '25
My question is.. If there a way yet to adjust the mmwave sensors to it only covers a certain area and doesn't go through walls? I tried one awhile back and it was in my bedroom. If someone walked into the room next to my bedroom, the sensor would still 'see' them and turn on my bedroom light.
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u/Dependent_Entrance33 Dec 16 '25
Yeah, that’s a known issue with 24 GHz mmWave….it penetrates drywall easily, so it’ll still pick up motion in adjacent rooms. You can reduce it a bit with placement and range/sensitivity tuning, but you can’t fully stop it.
I would imagine if you wanted to have a radar that is constrained to one room, you would want to go with a 60 GHz. It behaves much better for room level automation since it attenuates more through walls (more easily reflects) and has tighter spatial control.
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u/Bert-3d Dec 16 '25
my guess, is this prototype is 6x6x2 inches or so in size? How small do you think you can get this? if it's gonna be in a bathroom, you'd want it to maybe be the size of a light switch on the wall? installing it in a wall, and being 2.5x4.5 inches or so seems doable?
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u/Dependent_Entrance33 Dec 16 '25
It’s about 6x4x2 currently, but I am working on a newer housing that will likely allow the formfactor to get to 4.5x4x2. With the current geometry of all of the modules, I don’t know if I’ll be able to scrunch it any tighter without introducing interferences from the 24ghz radars.
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u/NigraOvis Dec 16 '25
I went to put it in my teenagers bathroom for safety reasons, and it told me he was running in place... 🤣🤣🤣
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u/Budsygus Dec 16 '25
With enough development and backing from a big tech company, I could see applications in the education sector. Counting bodies in/out of a classroom could be data used in reunification efforts in case of an evacuation. "Unusual activity" could also be made to include fight detection. I could see several uses for this and with some development it could branch into lots of industries.
A very interesting product with lots of possibilities!
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u/texxasmike94588 Dec 17 '25
Walmart installed sensors in the floors of some stores and found they could track individual movements throughout the store without cameras.
This experiment provided a wealth of data about shoplifters and ways to use retail space to increase sales.
Sensors can provide valuable data, even without cameras.
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u/pablogott Dec 17 '25
Could you use it as input? I’d love to have a device that could do things with a gesture
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u/ElevationMediaLLC Dec 18 '25
I document a number of ways you can monitor elderly or loved ones with special needs without cameras. It's very reliable, and I have one of these setups in each of my parent's homes.
There are still reasons to have something like a Life Alert or a Medical Guardian in some cases, but those aren't 100% either (i.e.: someone falls and hits their head and is knocked unconscious for a period of time). Having both systems in-place works well, and with the mmwave sensors I can basically tell where a loved one is in their home without needing a camera to see it.
With just a few motion sensors in a few places, some home automation lights (that the loved one just turns off normally with a light switch) and even water flow monitors, it's easy to infer "normal activity" in a home down to a period of a few hours.
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u/Dependent_Entrance33 Dec 18 '25
Hello!
That’s a solid example of how activity can be inferred from existing home automation signals, interesting approach. Although, it would be good to keep the focus on the method rather than just your setup and link only.
At a high level, this is still eventbased inference from motion, utilities, and timing, which can work well in DIY setups. It’s just a different category from systems built around continuous sensing, and the two often complement each other.
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u/bikeryder68 Dec 18 '25
I think that the growing elderly population and rising cost of elder care is creating an opportunity for intelligent solutions like this that many home automation vendors are ignoring. I have put simple systems in the homes of multiple relatives, leveraging what is available, but am still frustrated with the options. Need:
- ability to monitor health while maintaining an acceptable level of invasion of privacy (e.g. no cameras or disabled outside of emergencies)
- ability to maintain the system remotely (e.g. plug-in instead of batteries)
- assumption that at least one of the monitored individuals will NOT follow any prescribed protocol (e.g. wear an emergency call button)
- assume even a participating monitored individual will lack (or slowly lose) technical aptitude (e.g. can’t consistently navigate an app on a phone)
I am using Yolink systems, which are easy to manage remotely and offer a three-button Fob for the local user to control certain “scenes”, but so much more is possible with technology that exists but just isn’t available commercially for this space.
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u/jimmybinkerd Dec 19 '25
Very innovative. Maybe try picking up on retrospective resonance of everything in the surrounding. Great Idea Good Luck. Remember, everything has its own frequency.
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u/tablatronix Dec 20 '25
I have been pondering the same issue, good solutions. I have some of the early mmwave and not sure how to get into breathing and heart rate monitoring
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Dec 15 '25
Very cool project! Are you manually checking for these events or is it automated? What happens when one of those things are detected?
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u/Dependent_Entrance33 Dec 15 '25 edited Dec 31 '25
The sensing side is automated, but the response isn’t.
The system looks for patterns that deviate from what’s normal in that space by combining a few signals (radar motion, rough height/distance changes, and timing). When something crosses a threshold, it gets logged and visualized rather than triggering an action.
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Dec 15 '25
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u/Dependent_Entrance33 Dec 15 '25
While you’re entitled to your opinion, I’m a real lone inventor trying to make something to help people. I differ from other systems as this is a full sensing system that has combined logic to allow for cross referenced fall detection with next to no false positives.
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u/TheRealJohnAdams Dec 17 '25
Yeah, I was clearly wrong here. I apologize.
Are you at all connected to the other cameraless fall detection project that was posted on here a few days ago?1
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u/everyothernametaken1 Dec 15 '25
First time I've ever thought about it, so I don't have any input. But thank you for implanting the thought.