Dementia

Sorry, but no device can keep someone safe at home. Person with dementia cannot be trusted to activate the device when required and left alone may fiddle with the controls, put them away or lose them. If you are thinking of a surveillance camera then it would only be effective if someone was watching it 24/7.

I am a member of Talking Point forum and see there that Carers attempting to monitor their PWD from a distance, tend to suffer MORE stress than Carers who have committed to never leaving the PWD alone.

Does she live with you or on her own?
My H has dementia and I spent about 18 hours a day constantly with him or certainly in ear/shot.
The only sure and certain device is a human being.
I hope your mum is a little more independent for your sake.
Ask your Social Worker about a device which registers falls. I can't remember what it is called.