When will i learn???

...that if you dont turn the oxygen concentrator on it will not turn air into pure oxygen as it is supposed to but will just "alarm" causing the same effect in me.. yup I did it again last night... child asleep, unravel the tubing and mask, turn machine on and "BEEEEEPPPPP!!" This is not the first time so I should know to check... somehow looking at the little light that comes on too isnt going to make it work but that is what I do.. I am just about to go get the emergancy cylinder and then I realise... SWITCH IT ON AT THE PLUG!!!
Perhaps due to tiredness or being a little emotional?? Nah, just me being me! Lol. No point to the post, just a snippet of life in our house last night. :-)