[Solved] ZigBee busbar relays: status monitoring, Wi-Fi-free control and dedicated tablets

I have a couple of questions about the ZigBee system.
1. do the ZigBee button relays work in such a way that when you wire it up with a traditional candlestick light switch, the relay "knows" what state it is in?
In other words ? if I switch a light on with a push button, it knows it will be permanently short-circuited until I switch it the other way. Will I be able to switch it off via ZigBee in this state?

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2. as I understand ZigBee is a communication protocol independent of Wi-Fi, but is it possible to control the devices in case of an internet outage (being at home of course)? If so, how?
3) Are there any dedicated "tablets" for ZigBee that can be hung on the wall to be something like a Satel control centre?

Hello,

silencer7 wrote:

1. Do the ZigBee button relays work in such a way that when you wire it with a traditional candlestick light switch the relay "knows" what state it is in?
In other words ? if I switch a light on with a push button, as you know there will be a permanent short circuit until I switch it the other way. Will I be able to switch it off via ZigBee in this state?

.
From what I gather the module detects a change in the state of the switch and responds by changing the state of the relay controlling the bulb.

silencer7 wrote:

2. As I understand ZigBee is a communication protocol that is independent of Wi-Fi, but is it possible to control the devices in case of an internet outage (being in the house of course)? If so, how?

.

ZigBee is a radio communication standard that is independent of and unrelated to Wi-Fi. To control devices over ZigBee you need to be able to transmit and receive signals from this network. Depending on what you want to base control of the whole thing on, there are different approaches to this. For example, you need a USB/Zigbee converter or a gateway to "translate" the Zigbee signal to Wi-Fi.... It all depends where you want to plug it in.

Generally, such and other modules serve as terminal modules in smart home systems (generally called that). These systems have different approaches... Some are on an external server, so require an internet connection, others are set up locally, e.g. on a computer at home (e.g. on a Raspbery Pi). There is e.g. Home Assistant, Domoticz, Tuya, Supla.... There are easier ones, more difficult ones... You have to read and choose something.

silencer7 wrote:

3. Are there any dedicated "tablets" for ZigBee that can be hung on the wall to be something like a Satel control centre?

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I can't think of any, but maybe they are.

(1) As far as I know, such Zigbee switches require a momentary button (like for a bell) and it doesn't matter whether the switchover occurs after receiving a Zigbee command or a pulse from the switch. It is a separate thing to remember the state after a power loss - in most such devices this has to be configured by setting the appropriate value for the onOff cluster attribute.
2 Yes this is an independent protocol from WiFi. In order to directly control such a relay (without the need to install gateways, usb dongles, etc...), the easiest way is to buy remote controls, e.g. IKEA Tradfri - from the photo I can see that it is Zigbee3.0 so such a remote will pair by find&bind without any problem.
3. e.g. Aqara S1 (there is a cheaper S1E but no Zigbee)

3. bought an ordinary tablet. A wall mount for it. I control via the smart home app.
I control other devices via separate apps elmes module, airmobile, emodul, rainbird, weback etc.
In time I will switch to HA.

There are also already products: Tuya control panel Touch panel 4" scene control ZigBee dimmer TUYA

I have let the zigbee topic go for now, but thank you for your replies.