How big can a group be?

I’ve a problem when I try to let all my items be in the same group. I would like to have a group that turns off all my lights when I go to sleep, so I created a group and let all my things (13 different ligts) be part of that. But when I create a rule that shall turn that group off, not all of the things turns off. I trigger the rule with a Nexa-switch and if I push the switch more than one time then the lights that didn’t turn off the first time do it the second or the third time or not at all.
If I just put one of the things that didn’t turn off alone i the rule it works.

So my question is, how many things can there be in a group and how fast is the different things in a group get the signal to turn off?

Hope you understand what i try to accomplish and what the problem is.

Please post your Group, one or two of your Item definitions, and your Rule.

There is no limit to the number of Items that can be a member of a Group but something else must be going on. Some technologies cannot handle too many commands being sent really fast together so I suspect something like that is going on but without seeing the Rule you are using I can’t say for sure.

Here is the group.

Group God_Natt_Lampor
Group:Switch:OR(ON, OFF)	God_Natt	"God Natt [(%d)]"		<light>	(God_Natt_Lampor)

Here are some of the items.

Switch Bedroom_Window_Lampa	    "Fönsterlampa Sovrum"	 <light>		(Sol_Ned, God_Natt)			            { channel="tellstick:switch:1:11:state" }
Switch Gillestugan_Golv_Lamp	"Golvlampa Gillestugan"	 <light>		(Floor_Lamps, Sol_Ned, God_Natt)		{ channel="tellstick:switch:1:8:state" }

Dimmer Lampa_Tak_Sovrum		"Taklampa Sovrum"	<light>					                                                { channel="tradfri:0220:gwb072bfb34217:65538:brightness" }
Dimmer Lampa_Tak_Hall_01	"Taklampa hall 01"	<light>		(God_Natt, Lampor_Hall, Alla_Tak_Lampor_Utan_Sovrum)		{ channel="tradfri:0220:gwb072bfb34217:65539:brightness" }
Dimmer Lampa_Tak_Hall_02	"Taklampa hall 02"	<light>		(God_Natt, Lampor_Hall, Alla_Tak_Lampor_Utan_Sovrum)		{ channel="tradfri:0220:gwb072bfb34217:65541:brightness" }

Switch Bedroom_Switch_01	"Lysknapp sovrum"	<light>						{ channel="tellstick:switch:1:14:state" }

And finally the rule

rule "Godnight remote rule"
	Item Bedroom_Switch_01 received update OFF
	if(now.getHourOfDay >= 05 && now.getHourOfDay < 21)
		sendCommand(Lampa_Tak_Sovrum, OFF)
		sendCommand(God_Natt, OFF)		

        createTimer(now.plusSeconds(7)) [|
        	    sendCommand(Lampa_Tak_Sovrum, OFF)

There are totally 7 tradfri items and 6 tellstick items in my setup. The Bedroom_Switch_01 is a wall mounted switch.

The groups and Items look good to me so I’m going to assume the problem is that the technology can’t handle really really fast commands. So let’s put some delays between the commands. Replace sendCommand(God_Natt, OFF) with

God_Natt.members.forEach[light |
    Thread::sleep(500) // you will have to experiment with larger or smaller values to find the minimum sleep necessary to work

If that works we will address the problem of that many/long of a sleep could cause problems of its own. But it isn’t worth going down that path until we know it will fix the problem.

Thanks for a quick reply. I will test that the day after tomorrow (busy tomorrow) and come back with the result.

Now I’ve tested to see how to fix my problem and it turns out that it was me. I didn’t know that I could set a repeat value for each of the tellstick things. So when I did that everything worked. The repeat value tells openhab how many times it shall send the same command to the thing.

Thanks for all help.

Nexa is a simple broadcasting technology and the devices that listen will have problems when too much is sent via the airways.
When you send a command, example ON, your nexa sender will then send this command several times (it’s in its protocol) hoping the commands will reach the devices. When you send a lot of commands they will flood the sender and then the sender will flood the airways and your devices will miss the commands as you say.
When you make openhab repeat the commands you just flood the sender/airways more.
You will most likely experience problem from time to time as you did not fix the problem, but just increased the commands to be sent out and it worked for time being.

As for TRÅDFRI, it is zigbee so you should not have any problems there other than the gateway is a problem in it self with somewhat non functional firmware at the moment.

I would advice you to try to switch no zigbee or zwave instead of nexa.

Thanks for the explanation on how it works. It was something like that I thought.

I’m thinking of switching to zwave but they are a bit expensive so I will change item by item under some time. And I hope that it will get much better with that.