Should I use mmWave motion sensors?

Hardware
1

Hey! So I’ve got a general question regarding hardware for motion sensors.

Basically I’m setting some lights to turn on when there’s motion and presence. Motion turns it on, presence keeps it on. And I want to see which hardware is the better option, taking account their negatives too.

Now, on AliExpress I did order a ZG-204ZV (mmWave, 10G afaik) and a SNZB-03 (PIR).

The mmWave is faster to react (sub-second reaction), it operates on rechargable AAA batteries. The battery level did go down a lot in the past month and a half (from ~100 to ~50, at least on Z2M, it might not be calibrated for my battery cell type) but that’s with me (being an idiot) not setting a proper fade time of at least 10 seconds (it was 0, whoops) and not setting a fade time for the lumen sensor (another whoops).

Website info:

Standby Current:<80uA
Standby Time: >8 Months

The PIR takes more than a second to react. It’s a coin-cell battery which I’ll have to buy when it’s empty, but from what I understood, it’ll last way longer just from it being passive.

Website info:

Battery Type: CR2450
Battery Life: 8-10 months

But from reading the specifications, it looks like it’s pretty much the same in runtime-expectancy.

Does anybody know how much mA both devices pull during an average time of 24h?
And also is my PIR super slow, with it reacting after a second?

For the PIR I did have to tape the bottom half of it, so that it’s not triggered by my cats (so they don’t start a lightshow at 4AM when they get the zoomies). The mmWave didn’t need any kind of physical modifications.

Oh and another note, I’m from Serbia so ordering from Amazon does have its’ complications, it’s far easier (and way cheaper) to order from Aliexpress/Alibaba.

1 Like
2

For the SNZB-03, this is the only way I could get them reliable: (rechargeable batteries)

https://nl.aliexpress.com/item/1005008980599463.html

3

I’ll then have to buy a new charger (not an issue) and the batteries would only be for those. AAAs are more universal. Side question, how much does your sensor last for before having to swap batteries?

4

https://nl.aliexpress.com/item/1005009453871253.html

Not sure, before there were CR2450 in it, and I got a lot of false positives. Now 3 months a LIR2450, not a single false positive.

The ZG-204ZV is definitely better.

5

I am so surprised the concern about someone not moving which is an issue with PIR sensors is not dicussed here (yet!)

6

The ZG-204ZV is a mmWave sensor, but acts as a motion sensor. Not good for not moving objects.

7

I did mention I have a presence already. Which works for me but also cats. I need a motion sensor near my door which is kind of a gate for the occupancy to be sensed (which isn’t triggered by the cats).

Motion turns it on, presence keeps it on.

The dillema was just whether I go for mmWave or PIR for motion, mostly due to latency vs battery life.

8

If you’re willing to be patient for a little while longer, the Aqara FP300 should be out soon & advertises a battery life of 2-3 years on zigbee, depending on settings.

No idea on pricing or availability though - I’m just waiting for it to be available so I can try one.

9

Just looked into it. On some sentences it’s a motion sensor, on some it’s a presence sensors, we’ll see.

I doubt it’s going to beat the 7EUR price of the aforementioned devices.

10

It’s got both mmwave & pir, hence the inconsistency. And no, it won’t cost 7eur - I expect it to cost close to 10x that price

11

As of now it’s inconclusive which route I should go with. The JYSK batteries I have are, after 2 weeks of sitting stale, charged @ 1.31V (though there were close to 1.4V when there were off the charger).

The mmWave sensor with 1 minute presence timeout and 5m lumen timeout is charged at 1.29V after 2 weeks of usage.

I’ll have to get a proper charger for NiMH batteries and then test it out, I fear they’re not properly charged.

The PIR though has the battery sitting at 3.07V which I got in the original package from China, so definitely a longer usage period, but it does have a dead zone with how my doors are indented so it’s a significant tradeoff.

Edit:

The battery charger I have is almost as old as I am ahaha.