Sonoff Motion Sensor Review: PIR or radar sensor, which once is better

[@KimmoJaskari]

I believe the presence sensor maxes out at 4-5 meters or something like that on high sensitivity and less in medium sensitivity? So one probably needs to keep that in mind when placing those.

[@csongorvarga]

Thanks, it makes sense.

[@lukaszsabinicz6415]

What a great set of tests! Thank You.

[@chuxxsss]

Can you hack the pir sensor? It's been a while since I saw your channel. 33 K sub good work. The radar sensor has a rear lobe from the Antenna and side lobes. Ex radar technician plus calibration technician here.

[@csongorvarga]

Thanks. What do you mean hack the PIR sensor?

[@Txusintox]

I have bought 2 devices and I have placed them in the bathroom, my intention is to turn lights and sockets on and off but I have problems, I have placed them in different areas with different sensitivities and in all cases I have had false positives. Why can this happen to me?

[@csongorvarga]

You mean the light is on when nobody is in the bathroom? Is is possible that it pick up movement when you walk by in front of the open door? Like when it picked me up even when I was behind the sensor?

[@Txusintox]

@@csongorvarga I don't pass near the door, that's when I pass through the wall, imagine a hallway and to go to the bathroom door I have to turn left, the door is 3 meters away and the sensor is oriented in the direction of travel that I mention, Well, without getting closer, there are times when false positives occur.

[@csongorvarga]

@@Txusintox Yes, it was pretty much me observation as well. PIR sensors always need a line of sight from the sensor to the object being detected, but with radar I assume some reflections from a wall, mirror or tile can trigger detection. I am afraid you can to play around with placement of tweak the aim of the sensor until you can elliminate the false triggers.

[@thecraigmcrae]

Thanks, very useful comparison.

[@dominicdechangy8365]

Excellent report with lots of serious scenarios: great job !

[@csongorvarga]

Thanks

[@zyghom]

Super nice and deep review. 1 - @02:16 - yes and that is the reason why you create a helper in HA, a timer. Set it for i.e. 5min. PIR starts timer, when time starts, light turns ON. After 30s PIR will go off but you still have light ON due to timer. There is no way you will not move during 5min. Next time PIR detects movement it restarts the timer and again you have 5min. That is how I do with all my PIRs. 2 - Also I realized that Zigbee PIR sensors are much slower than ESPnow PIR sensors. 3 - each PIR sensor that is battery operated goes to UNCONDITIONAL sleep after reporting motion. This is how these sensors save the power. No motion within this time wakes up the sensor. Otherwise they would die few days on these small batteries. Some sensors have this time adjustable, some not.

[@csongorvarga]

Thanks a lot for these comments. I new about 3) but forgot to add it. The helper timer is a really good option.

[@TrickyTree84]

I just put motion stopped 5 mins ago trigger and conditions in the automation. Do I really need the helper?

[@zyghom]

@@TrickyTree84 it is up to you but what I do is also: 1- apart from motion triggered timer (on, then off on its own) 2- I also start timer when someone turns on the light by the switch on the wall - then again: light goes on immediately and also timer starts - then light goes off when timer expires

[@srinivasdeverakonda4310]

Is the light sensor usable within ewelink app? Do the default dim and bright light triggers in scenes make it practical for every day application?

[@csongorvarga]

As I have shown, unforutnately there is no separate trigger just for light sensor, only in combination with motion sensor. Maybe gets added in the future.

[@srinivasdeverakonda4310]

@@csongorvarga what I mean to ask is - does dim light trigger within scenes in ewelink app accurately calibrated that light is being turned only when ambient light is sufficiently low that you would actually want the light to be turned on in the room?

[@csongorvarga]

@@srinivasdeverakonda4310 Well that is my problem. Since it does not show light or dim on the UI, I can't really tell what is the threshold for the sensor. And it cannot be set either (how dim is low light).

[@srinivasdeverakonda4310]

@@csongorvarga thanks a lot for the info.

[@csongorvarga]

@@srinivasdeverakonda4310 I did not play with those scenes so I did not find out what dim means for this sensor. And I don't like the fact that there is no information on this on the screen at all. So I would need to run a lot of expperiment to find out.

[@exqmedia]

Hi Varga! The only issue with my sensors Sonoff SNZB-03 is that if I work in front of them for 6 - 8 minutes sometimes PIR does not detect me even I am moving. Sensor getting stuck in a detected state or not re-triggering an automation within the refractory period. Did you try to walk in coridor for 8 minutes to see if SNZB-06P detect you every time?

[@csongorvarga]

Yes, that is a problem with battery devices. After they detect motion, they usually go to sleep to save battery. I guess this is one more reason the radar sensor is USB powered. So far the 06P detected me every time.

[@antonzemanek7770]

Thank you for the review! Ideas for testing. 1) While being on WC, if the sensor reacts on somebody's presence behind the door or wall. 2) If it is able to detect motion through a wall if it is intended (e.g. if I place a sensor in WC direction to the bathroom and want to react to somebody's presence in the bathroom). 3) If placed on balcony, if ONLY reacts on human presence, e.g. does not react on wet cloths, that might be placed there. Thanks!

[@csongorvarga]

Good points. I don't think it detects through the wall. On the scenario when I was opening the door and coming back to my home office, the sensor did not trigger until I opened the door. So probably not sensitive enough to trigger through objects.

[@antonzemanek7770]

@@csongorvarga you can test it. I saw a video with a use case, how the other presence sensor is hidden behind a tile and detects motion through it. Another valid use case may be hiding the sensor in a piece of furniture. So if you include this into a follow-up video, it would be much appreciated

[@csongorvarga]

@@antonzemanek7770 I also had a DIY radar sensor and it did the same. It was also detecting motion when it was facing the other way. But thin materials would certainly work...

[@antonzemanek7770]

​@@csongorvarga it would be useful to know that it DOES NOT detect thorough a wall or a door prior to buying the sensor, so that it would not catch somebody's presence when not desired.

[@csongorvarga]

@@antonzemanek7770 It definitely does not do that, otherwise the sensor would have detected presence even before I opened the door.

[@T163R]

Hi All, Can this presence sensor be used without a power supply and if so, how long do they last ?

[@csongorvarga]

The presence sensor is wired only. You can connect it to a powerbank, but it will be still wired to something. I did not check the power consumption. I don't think it is huge, be definitely more than what a coin cell or a double AA batteries can run for a few months.

[@jdabramson]

Thank you

[@theattorney6072]

Hi, could you please tell me what is the detection angle of the sonoff presence sensor ?

[@csongorvarga]

That is a good quesiton, in my test I was approaching the sensor from the front (maybe in a 90 degree wide area), but as shown in the video it did pick me up even from behind the sensor. So the detection angle may not be that relevant as it can detect from reflection as well.

[@user32186]

I wonder how it will work out a garage?

[@csongorvarga]

I think it would, this is based on radar detection, not infra red, therefore it does not need a hot body to detect motion.

[@theattorney6072]

It appears the sonoff exposes two sensors to zha, a motion sensor and a presence sensor.

[@csongorvarga]

Oh great, in Zigbee2MQTT I could only see presence information. Maybe one is derived from the other in ZHA to support both presence and motion events.

[@theattorney6072]

@@csongorvarga I don't know, I am still waiting for mine to arrive, however the motion sensor exposed in zha appears not to be working properly (yet?). Maybe will it work better After full support in zha ?

[@csongorvarga]

@@theattorney6072 I have seen some radar sensor that you can fine tune with sensitivity and detection range. I think this is probably pre-configured to some typical value and I don't think there is any option to change that. And I am not even sure if Zigbee standard itself supports a lot more for radar sensors.