Small, cheap, battery powered Smart button

Hi, I’m looking for a battery powered Smart button with one, or better more, inputs. Can be DIY.

Some use cases: doorbell, light switch, door/window sensor, cabinet drawer/door sensor, detect gas meter counter with a reed Relais and more.

I could use an ESP32 or similar, but I don’t necessarily want WLAN because I don’t want to overwhelm my router. And I’m not sure if the battery life is good or not.

It should be small enough to fit behind a regular (German) wall switch (size of Shelly devices).

Ideally it can run with a 3.6V Lithium batterie (AA size) and I can read the battery level in Home Assistant to create an alarm for low battery.

Summary: I need something like the Shelly Plus i4, but cheaper, battery powered and not necessarily with WLAN.

Any suggestions?

The cheapest I have is a rf433, it only has 1 action though. At ali you have plenty of choice at <4EUR

But for the RF433 I also need a receiver. And you need a receiver for each transmitter, right?

Something like this?

Then you need something like an Arduino or ESPhome device to forward the receiver signal to HA?

Agreed, but you mentioned not wifi :slight_smile:
I tried a sonoff zigbee one (which would also need a receiver) but this is 2x as expensive and for my simplistic use…rather pay half…but this is personal decision of course. The zigbee one has single/double click

And long press as well.
The battery life on them is really good.

Not mine, which was unexpected … so do read the add & reviews when you buy one (I did not)

Not particularly cheap at Euro 15, but Shelly make good stuff.

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I think, Bluetooth is not a good solution for me (and for Smart Home in general). And I don’t want to span another wireless network in my home. I think, WLAN, Zigbee and DECT are enough.

I ordered some ESP8266 devices to play around. I try to run them with 3V button cells. Maybe it works for me.

Really!?! :angry:
So there are different versions?