So I am looking to get precense detection in my living room. I think I want mmwave as I do want to detect people that are sitting on the couch for example. And I saw most don’t have a large distance and angle as my living room/kitchen is 8m by 12m(in an L shape) so most with a 4-6m detection distance are not enough. Also regarding the price I am looking at esphome with a hi-link sensor. But I would like to get some recommendations if I should get a LD2420 or LD2410. Some say the 2420 can’t detect a stationary target but the 2410 has less range(6m vs 8m). So I thought place 2 LD2420’s for 120 degree 8m coverage in the corner of the L with a esp8266. Would this work for stationary targets? (it doesn’t have to be able to differentiate between the two just not be like a infrared motion sensor). Also if you have done this and have found problems or something to share please do so. Thanks for your sharing experience with one or both of the sensors and your knowledge about this topic.
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I’ve been messing around with the MR60FDA1 60GHz mmWave detector in esphome and Home Assistant. Unfortunately it has the same 6m range and 60° field of view you’re looking to get around.
I will say, though, that within range the sensor is quite responsive, and detects static presents quite well. The high frequency gives it sufficient resolution to detect micro movements like fidgeting, looking around or even breathing. My module has fall detection on board, purportedly to sense if a detected person is standing or laying down. Another version supposedly can detect respiration and heartbeet within a couple of meters.
The good thing about 60Ghz is they tend not to interfere with each other, so several units could be arranged with overlapping fields of view.
I’m pairing mine with a PIR module for rapid detection, and to help eliminate false positives on radar hits since radar can see through walls, and doesn’t necessarily expose the distance to the target in esphome.
The 24GHz models have a longer range up to 12m and may have 360° fields of view, but have lower resolution and ranging for micro motions. In the US, they are being phased out for potential interference with aviation though I can’t speak for other countries.
Andreas Speiss posted a good video on YouTube that covered a bunch of different models (link below) that I thought was informative. It will.lead you to some other similar content that might help you to assess your needs and match a product to your application.
Andreas Speiss - Radar Sensors from $3 to over $100: Which is Best?
https://youtube.com/watch?v=s-GzUTyIH9cI looked further into my assertion that 24GHz radar was being phased out, since something was bothering me about it. It seems 24 GHz Ultra Wide Band (UWB) applications are no longer approved, but 24GHz Industrial, Scientific & Medical (ISM) applications are still approved. Home use of 24GHz radar would be considered ISM, so there is probably no restriction on its use.
Sorry for any confusion…
Interference never though about that good to know might go 60ghz then and get 3 for 180 degree coverage. Also they can look through walls? Also trough wood or concrete or only the american paper walls? As this would be amazing for my hallway where there is a staircase kind of in the way.
Also what do you mean by fast detection are the radars not enough for someone walking by?
Interference and crosstalk: Both 24GHz and 60FHz mods are tolerant of other emitters in their field of view, so you could pair two of them in the outside corner of your ell, looking towards the ends and a third at the long end of the ell looking back towards the corner and they ought not to interfere. Another possible configuration would be three ceiling mounted emitters looking down, overlapping the fields of view for full coverage of the floor area. A 60° field of view at 2.8m gives you roughly a 5m radius of detection on the floor.
Seeing through walls: “Thin walls” attenuate the signal, but allow enough penetration to detect people through cover. The radar can penetrate thin plastic housings, plexiglass, cloth, drywall, wood paneling, and thin plaster & lath. It cannot penetrate glass, stone, or metal. Same goes for floors. My radar module will detect people in the unfinished room below my home office through the hardwood floor if I angle it down far enough.
Fast detection: I found that while the radar was responsive even to small movement nearly instantly, it takes up to 2 or 3 seconds to acquire and classify a target as a person. Once t locks on, it pretty reliably tracks the person for as long as they are in view. In practice, a person walking into the edge of the field of view at a normal walking pace could cover half the field before they are detected as present. It “feels” a bit slow compared to PIR detection which is sub-second in most cases, but generates a lot of false positives. The technique I am refining is to position the the radar to detect a person entering a room by angling the radar field of view to “lead lead target” and use the PIR to determine the target has moved into a zone where I want action to take place. In essence, I want the lights to trip on when the radar detects human presence AND the PIR sees a hot blob. Then I kick on the light and wait for the human presence detection to go back to unoccupied for 5 minutes before turning off the light. I might also experiment to see if ultrasonic detection is any more reliable than IR, since it wouldn’t be fooled by warm/cold draughts, or by sudden changes in light as from dappled shade or clouds & sun. My concern is I have pets and wouldn’t want to stress them with sound I can’t hear, but maybe they can. Need to research it more.
Its been fun playing with this stuff, but I might note that at this point you can just buy an open platform (as in open source) esphome/HA compatible multisensor presence detector made by the guy who does the Everything Smart Home channel on YouTube. He posted a couple videos talking about it (links below). For me, this is just messing around with something I always wanted to play with, but I’ll probably just buy a kit when I want to hang something functional on a ceiling or wall.
Definitely check out the videos I linked. They’re excellent for helping to understand the pros and cons of this tech in real-world smart home applications.
Everything Smart Home - Building my own smart ho e oresense sensor
Thanks for your reply it really helps the video’s you linked I already found. and found that they where really helpful for understanding. Together with your experience I am probably going to experiment a little to(I like to make my own stuff to so not looking nice is less of a concern as long as it works). Thanks for explaining the few details I didn’t understand. I feel like they are a perfect tool for presence detection that together with something else are exactly what I need. Once again thank you for sharing your experience and knowledge
