Best sensors for a baby monitor

Hi

I am in the process of designing a baby monitor and I am deciding on what sensors to incorporate, currently I have decided on Temperature, Humidity and Pollution levels (MQ135). I am trying to decide on a 4th sensor for the product and I have shortlisted the following sensors:

Light (LDR) - Determines if there is too much ambient light Sound (Microphone) - Determines if there is too much ambient sound Nitrogen Dioxide - Effects some peoples Asthma as well as being generally bad for your health, comes from car engines Or any other sensor that you would find useful in a baby monitor

Thanks for your help :)

My generation would probably agree that a baby monitor was invented before mothers were made to feel inadequate without one.

Simple noise detection would be a given.

Weedpharma

Genetically engineered mother brain tissues matching the child?
Best solution to some is in the same room. I don’t know if you have raised children. Walking into a different room in the middle of night is worse than sleeping with a baby next to you.

well microphone yes you need to know if the baby is crying so its handy, baby monitors these days even has camera's so if you want one you need a camera with ir leds for night vision and a tft display for for watching the camera on the other side

LDR and Nitrogen sensor gives me question marks why you should use it for the baby monitor ?

what i would use is a room temp sensor, why? well even if you put the baby under the blankets it sure moves and at least their hands getting cold and so on, so you can monitor if the room is at a good temp.

and always put a smoke detector in the room.

or built it in your baby monitor in case of fire.