Using observers in Minecraft to pick up a signal from the bed?

hello, I build an adventure map in minecraft and when you go to bed a command block should be activated. I've tried it with observer (observers) under the bed but since there's somehow no blockupdate when you go to bed, is there another way to pick up a signal from the bed or a command that is suitable? Unfortunately, I did not find anything… (Bedrock edition on the PC)

I think that maybe you test by a command block if the player is in bed (that means a little bit lower than him).

Another idea would be to somehow test what time of day it is that if the player has slept and it is day, another value stands. (knows ned if it works)

both ideas are completely invisible, better than observer.

Thanks for your answer, unfortunately that does not help me much because the commandblocks I want to activate the time of day to a certain value with change. In addition, I do not have much plan of commands which is why I need a complete command that I can take into the game (only know the basics and a command that gives a signal when a player goes to bed nearby is I think more complex). But thanks anyway.

I mean there's a scoreboard that tests whether you are in bed, so you would know without Observer who as long as in bed.

The score is "minecraft.custom: minecraft.sleep_in_bed"

Source: https://minecraft.gamepedia.com/...Scoreboard

Have fun